Recent progress in all-inorganic metal halide nanostructured perovskites: Materials design, optical properties, and application

Abstract

Low-dimensional all-inorganic metal halide perovskite (AIMHP) materials, as a new class of nanomaterials, hold great promise for various optoelectronic devices. In the past few years, tremendous progress has been achieved in the development of efficient and stable AIMHP nanomaterials for optical property studies and related applications. Here, we offer a critical overview on the unique merits and the state-of-the-art design of AIMHP using different composition strategies. Then, the effects of material compositions, dimensionality, morphologies and structures on optical properties are summarized. We also comprehensively present recent advances in the development AIMHP nanomaterials for practical applications including solar cells, light-emitting diodes, lasers and photodetectors. Lastly, the critical challenges and future opportunities in this emerging field are highlighted.

Graphical abstract

Keywords

inorganic perovskite / nano-structure / materials design / optical properties / applications

1 Introduction

In the last decade or so, metal halide perovskites have received substantial attention in all over the world due to their applications in solar cells (SCs) [1–3], light emitting diodes (LEDs) [4–6], lasers [7–9], photodetectors (PDs) [10–12], etc. However, there are some concerns remaining during their practical applications, especially the instability of organo metallic halide perovskites (OMHP) and hybrid organic-inorganic metallic halide perovskites (HOIMHP). Recent studies indicated that the organic groups play a vital role for enhancing their photo and thermal stability because metal halide perovskites are extremely sensitive to both oxygen and water [13, 14]. Thus, most of the attention has turned to the enhancement of environmental stability by hybridizing with other cations such as Cs according to a tolerance factor [15], by surface modification with moisture-tolerant molecules [16], by integrating OMHP with polymers [17] and by replacing organic carrier transport layers with inorganic oxides [18]. Although various methods have been used to improve the stability of materials, the inherent instability of organic groups still hinders their practical applications, as shown in Fig. 1.

To overcome the challenges, the all inorganic halide perovskite CsPbX₃ (X=Cl⁺, Br⁺, I⁺) nanocrystals were successfully synthesized in 2015 based on the concept that replacing the organic groups with inorganic cations [19]. After that, the CsPbX₃ are rapidly emerging as promising alternatives because of their excellent stability and comparable optical properties and the prepared all inorganic halide perovskite CsPbX₃ nanocrystals have been successfully applied in the SCs [20–22]. Subsequently, many strategies have been developed for CsPbX₃ fabrication, including colloidal synthesis, anti-solvent, substrate evaporation, and substrate vapor transport [23]. By controlling the rich reaction chemistry in the preparation of inorganic halide perovskites, high quality and well-defined morphologies of zero-dimensional (0D) quantum dots (QDs) [19], one-dimensional (1D) nanowires (NWs) [24–27], and two-dimensional (2D) nanoplates (NPLs) or nanosheets (NSs) [28–30] have been achieved. Besides, recently reported works suggested that compared to the OHP and HOIHP, AIMHP with general formula ABX₃ (A=Cs⁺; B=Pb²⁺, Sn²⁺, Ge²⁺; X=Cl⁺, Br⁺, I⁺) are a promising alternative with attractive properties, such as high quantum efficiency [19–31], high carrier mobility [32, 33], narrow emission peak [34, 35], and exhibit higher stability and have many potential in various optoelectronics, including SCs [36, 37], lasers [38, 39], LEDs [40, 41], and PDs [42, 43].

Obviously, inorganic halide perovskite nanomaterials provide controllable morphology and tunable optoelectronic properties and can effectively improve the stability and performance of materials and devices [44, 45], which offer excellent platforms for distinct fundamental research and practical applications in the near future. Thus, a timely review on such a rapidly growing field of great significance is highly desirable. Following this line of thought, in this review, we summarize the synthesis, optical properties, and applications of AIMHP materials from their discovery to date. At last, we also discuss the challenges facing the field of AIMHP and some possible solutions based on the available literature are suggested.

2 Synthesis of all-inorganic metal halide perovskite nanomaterials

AIMHP nanomaterials have at least one dimension at the nanoscale (<100 nm), such as QDs (or NCs: nanoparticles), NWs (or nanorods), and NSs (or thin films). These materials have demonstrated excellent optical and electrical properties different from their bulk materials due to quantum confinement effects (QCE) and strong anisotropy [46–50]. In this part, we will review the progress of AIMHP nanomaterials in recent years, based on the differences of dimensions. Different synthesis approaches and growth conditions will be discussed along with their novel characteristics especially optical and stability properties.

2.1 All-inorganic metal halide perovskite 0D nanomaterials

In recent years, all-inorganic cesium lead halide perovskite CsPbX₃ (X=Cl, Br, and I) NCs have attracted a lot of attention due to their excellent properties, such as high photoluminescence quantum yield (PLQY), broad wavelength coverage, narrow PL emission bandwidth, and low trap state density [51–54]. These outstanding properties of CsPbX₃ NCs distinguish them from traditional semiconductor NCs and make them promising candidates for various optoelectronic applications.

As mentioned many times before, Protesescu et al. synthesized CsPbX₃ colloidal NPs for the first time by hot-injection method [19]. The CsPbX₃ colloidal NPs exhibited a cubic shape with a size of 4–15 nm and cubic perovskite crystal structure. Through compositional modulations and QCEs, the emission spectra are adjustable from 410 to 700 nm. Since then, many methods have been developed for the synthesis of CsPbX₃ NCs, such as solvothermal synthesis [55], post-treatment [56], ultrasonication [57], and mechanochemistry [58]. However, researchers still face challenges to achieve highly stable and photoluminescent CsPbX₃ NCs at room temperature by the direct-synthesis method [59].

Nedelcu et al. and Akkerman et al. further realized fast anion exchange in CsPbX₃ (X=Cl, Br, I) perovskite NCs at low temperature [60, 61]. By adjusting the halide ratios in the colloidal nanocrystal solution, the bright PL could be tuned over 410–700 nm while maintaining high quantum yields (QY) of 20%–80% and narrow emission line widths of 10–40 nm. Furthermore, the fast inter-nanocrystal anion exchange was demonstrated between the CsPbCl₃, CsPbBr₃, and CsPbI₃ NCs, leading to uniform CsPb(Cl/Br)₃ or CsPb(Br/I)₃ compositions. After that, there were many reports on CsPbX₃ colloidal NCs synthesized based on this method, but with different crystal phases. For example, Swarnkar et al. synthesized CsPbBr₃ colloidal NCs following the above methods, but obtained orthorhombic phase CsPbBr₃ [54]. Jellicoe et al. first synthesized lead-free CsSnX₃ (X=Cl, Cl_0.5Br_0.5, Br, Br_0.5I_0.5, I) perovskite nanocrystals and exhibited the tunability of the spectrum through both QCE and control of the anionic composition [62].

Inspired by the methodology for synthesis of perovskite MAPbX₃ colloidal NCs, Li et al. extended the supersaturated recrystallization method to synthesize inorganic perovskite CsPbX₃ [63]. These colloidal NCs have superior optical properties to those formed at high temperature, including PLQYs of 80%, 95%, and 70% for red, green, and blue PLs, and a 90% retention rate after aging for 30 days under ambient conditions. Deng et al. used a reprecipitation strategy to systematically manipulate the shape of colloidal CsPbX₃ NCs, such as spherical colloidal NCs and nanocubes, by using different ligands [64]. De Roo et al. studied the dynamic ligand of the inorganic perovskite CsPbX₃ [65]. They found that compared to classical chalcogenide QDS, CsPbX₃ is more ionic in nature and the interactions with capping ligands are also more ionic and labile. Most recently, Swarnkar et al. [66] reported the synthesis of ambient stable cubic–phase QDs of CsPbI₃, a phase that was previously known to be stable only at high temperature. They have developed an improved synthetic route and purification approach that prevents the CsPbI₃ QDs from transforming their as-synthesized cubic phase to orthorhombic. Accurate control of emission bands and NC morphologies were vital prerequisites for most CsPbX₃ NCs practical applications. A facile method of synthesizing CsPbX₃ NCs in the nonpolar solvent octane was developed by Ye et al. [67]. The process was conducted in air at about 90℃ and the prepared high-quality CsPbX₃ NCs showing 12–44 nm wide emission with high PL quantum yield, exceeding 90% [67].

Since last year, core-shell structures have been used to further improve the optical properties and stability of AIMHP nanomaterials. Lu et al. prepared the CsPbBr₃/ Cs₄PbBr₆ core-shell structure NCs by means of a microchannel reactor. Without any protection, the outstanding stable NCs retain more than 90% of the PL intensity after 84 days [68]. Tang et al. were successfully synthesized CsPbBr₃/CdS core-shell structure QDs using a facile hot-injection method [69]. Chen et al. adopted an effective ion-doping strategy to improve the stability and efficiency of all-inorganic CsPbI₂Br and related SC devices [70]. Wang et al. got the mixed CsPbI_2.85Br_0.15 by adding 5% Br ions into the CsPbI₃ [71]. The optimized PSCs based on this mixed CsPbI_2.85Br_0.15 obtain a record reverse scan PCE of 17.17% and stabilized PCE of 16.83%, and exhibit excellent thermal and compositional stability. Zhao et al. synthesized CsPbI₃ NCs with different size distributions and studied the lattice structure and confinement properties based on this perovskite nanocrystals, as shown in Fig. 2 [72]. Their findings suggest that adopt the perovskite nanocrystal structure can effectively improve the stability over thin-film perovskite materials. As summarized above, intensive efforts have been made in the development of AIMHP 0D nanomaterials since the first study in 2015. Significant progress has been achieved in the controlled preparations and optimizations of AIMHP NCs properties over the past five years. Their promising applications in different areas have also been partially demonstrated. Despite these great successes, the research in AIMHP 0D nanomaterials is still in its early infancy objectively. In particular, the aforementioned issues of stability and toxicity of lead must be addressed before the widespread practical applications of AIMHP 0D nanomaterials become possible.

2.2 All-inorganic metal halide perovskite 1D nanomaterials

Among differently shaped AILHP nanostructures, the 1D AILHP NWs have demonstrated outstanding performance when used in lasing and PD devices [73, 74]. Various methods have been developed to prepare the AILHP NWs [75, 76], including oriented assembly of nanocubes [77, 78], solution-phase methods [79–81], ultrasonication-assisted synthesis [57], self-assembly process [82], vapor-phase growth techniques [83–87] and catalyst-free colloidal synthesis method followed by stepwise purification strategy [40]. A solution-processed method with surfactant ligand was reported to control the synthesis of all-inorganic perovskite CsPbX₃ (X=Cl, Br, I or mixture of halides) NWs [39]. This method was widely used for previous metal and inorganic semiconductor NWs, using a surfactant ligand as the capping ligand to initiate one-dimensional crystal growth. The CsPbX₃ NWs were synthesized under an air-free environment by reacting cesium oleate with lead halide in the presence of oleic acid and oleylamine in octadecene at 150–250℃ for 5–10 min. The as-synthesized CsPbX₃ perovskite NWs exhibit diameters less than 12 nm and lengths up to 5 mm and the yielding up to 90% after simple purification. Moreover, by an anion exchange reaction, CsPbCl₃ and CsPbI₃ NWs can be transformed from CsPbBr₃ NWs by reacting with other halide precursors. The NWs transformed from CsPbBr₃ NWs exhibit high quantum efficiency up to 83% and 30% for CsPbI₃ and CsPbCl₃, respectively [80].

Chen et al. reported a simple but efficient solvothermal approach to prepare ultrathin CsPbX₃ (X=Cl/Br, Br, and Br/I) NWs with almost 100% morphological yield. A strong QEC was observed in the ultrathin NWs, in which both the absorption and emission peaks shift to shorter wavelength range compared to their bulk bandgap [79]. The single-step ligand-mediated synthesis of single-crystalline CsPbBr₃ perovskite NWs directly from the precursor powders [88]. Studies of the reaction process and the morphological evolution revealed that the initially formed CsPbBr₃ nanocubes were transformed into NWs through an oriented-attachment mechanism. The optical properties of the NWs can be tuned across the entire visible range by varying the halide (Cl, Br, and I) composition through subsequent halide ion exchange. Single-particle studies showed that these NWs exhibit strongly polarized emission with a polarization anisotropy of 0.36. More importantly, the NWs can self-assemble in a quasi-oriented fashion at an air/ liquid interface. This process should also be easily applicable to perovskite NCs of different morphologies for their integration into nanoscale optoelectronic devices, as shown in Fig. 3 [89]. Shoaib demonstrates the directly controlled method to grow in-plane directional perovskite CsPbBr₃ NWs. The NWs have a very strong band-edge PL with a long PL lifetime of ～25 ns and can realize high-quality optical waveguides [90]. Then, the direct synthesis of composition-graded CsPbBr_xI_3–x NWs is reported by Huang et al. through vapor-phase epitaxial growth on mica [91]. The graded composition along the NW, with an increased Br/I from the center to the ends, comes from desynchronized deposition of cesium lead halides and temperature-controlled anion-exchange reaction. The graded composition results in varied bandgaps along the NW, which induce a blue-shifted emission from the center to the ends. As an efficient gain media, the NW exerts position-dependent lasing performance, with a different color at the ends and center respectively above the threshold.

Last year, Liu et al. generated the visible-light-induced template-free synthesis of CsPbBr₃ NWs through self-assembly cubic CsPbBr₃ NCs [92]. Then, a post-treatment method for the preparation of ultrathin CsPbX₃ NWs by treating CsPbBr₃ nanocubes with thiourea solution was realized by Li et al. [93]. The ultrathin CsPbBr₃ NWs exhibited high PLQY (up to 60%) and high resistance to water treatment. Monodisperse CsPbBr₃ nanorods with tunable aspect ratio and a clean surface have been prepared through an interfacial conversion from Cs₄PbBr₆ nanocrystals. The nanorods showed excellent photophysical properties, including a PLQY up to 87% and a PL lifetime of 44 ns [94]. Zhang et al. developed a self-assembled nanotemplate-confined growth concept to prepare ultrathin CsPbBr₃ NWs [95]. He et al. reported a robust polar-solvent-assisted route to 1D CsPbBr₃ NWs via room temperature supersaturated recrystallization. CsPbBr₃ NWs were rapidly yielded, experiencing a cubic-to-orthorhombic phase transformation and a blue-shifted emission [96]. Chen et al. adopted a vapor-phase growth method and successfully prepared aligned cesium tin tolerant CsSnX₃ (X=Br, I) NWs [97]. And, Meng et al. directly synthesized all-inorganic perovskite NWs by the method of vapor-liquid-solid [98]. A facile synthesis of quantum-confined CsPbBr₃ NWs by using a continuous-flow microfluidic reactor was reported by Zhang et al. [99]. Recently, Liu et al. introduced an amphiphilic block copolymer to chemically modify the surface of colloidal CsPbBr₃ NWs and a modified Langmuir-Blodgett technique to enhance the stability [100]. The resulting core-shell NWs show enhanced PL emission and good colloidal stability against water. As discussed in this section, the anisotropi-cally structured AILHP NWs and nanorods have been prepared using a variety of methods and have demonstrated outstanding performance when used in lasing and photodetector devices. But the biggest obstacle to practical application of 1D AILHP nanomaterials is still their component stability against chemical, thermal, and photo disturbances. At the same time, the preparation of ultra-long and ultra-fine one-dimensional nanomaterials with good optical and structural properties is also a huge challenge.

2.3 Nanomaterials

The stable CsPbX₃ NPLs were first reported in 2015 by Bekenstein and collaborators using the hot-injection method [28]. Since then, the emerging 2D forms of AIMHP are attracting more interest due to the long charge carrier lifetime, high PLQY, and great defect tolerance [101–103]. In 2016, Akkerman et al. have demonstrated the synthesis of the CsPbX₃ NPLs also by hot-injection method at room temperature [104]. They have shown that anisotropic growth leads to the formation of NPLs through the injection of acetone in a mixture of precursor. The low growth temperature facilitates the control of the plate thickness down to three monolayers. Wang et al. reported a facile fast precipitation synthesis of highly luminescent perovskite-related CsPb₂Br₅ NPLs and their fast anion-exchange capabilities to tune optical properties [105]. Their results also indicated that the CsPb₂Br₅ layered structure has the best stability during the exchange processes when the thickness of the ion-exchange nanosheet is about 3 nm.

In addition to the solution-based approaches, CVD was another important way to grow high-quality 2D materials [106, 107]. Their results suggested that selecting the ideal encapsulation and protection materials for halide perovskites during the processing or fabrication is important. CsPbX₃ perovskite NPLs were grown on muscovite mica substrates using the vapor transport CVD method [106]. Shamsi et al. improved the synthesis of CsPbBr₃ NSs by introducing shorter alkyl chain ammonium ligands to the reaction [108]. The results showed that the lateral size of the NSs is tunable by varying the ratio of shorter ligands over longer ligands. The perovskite multiple quantum wells (MQWs) with red light emission were prepared using the solution-processed self-organized method [109, 110]. Their results demonstrated that the perovskite MQWs are a promising platform that allows achieving high-performance visible-range EL emissions through high-throughput manufacturing processes, which is attractive for low-cost lighting and display applications. In addition, due to the broad tunability of halide perovskites by controlling dimensionality and composition, it is possible to build heterojunctions between different halide perovskites. An example of periodic lateral CsPbCl₃/CsPbBr₃ heterojunctions in single NPLs by the cation exchange method and nanofabrication technique was shown by Du et al. [111]. 2D lead-free CsSnI₃ NPLs have been synthesized for the first time by Weidman [112, 113]. These CsSnI₃ NPLs (with thicknesses of less than 4 nm) exhibit significant QEC with PL at 1.59 eV compared to 1.3 eV in the bulk. The results also showed that Sn-rich conditions in CsSnI₃ can reduce defect density and increase stability. Cs₃Bi₂Br₉ perovskite NPLs were synthesized for the first time via the hot injection method [114]. The Cs₃Bi₂Br₉ NPLs were parallelogram-shaped and exhibit an extremely sharp first exciton peak which blue-shifts substantially with respect to their bulk bandgap.

Tin-based inorganic halide perovskites, such as CsSnX₃ (X=Cl, Br, I), have been studied as promising candidates that avoid toxic lead halide compositions [115]. The single-domain epitaxial growth of CsSnI₃ on closely lattice-matched single-crystal potassium chloride substrates was demonstrated [116]. Liu et al. introduced a monolayer polystyrene sphere confined growth method for obtaining CsPbBr₃ nanonet films (NFs) with ordered nanostructures grown in the preferred (110) orientation, which is beneficial for the charge carrier transport and the light-harvesting efficiency [117]. Recently, high-quality CsPbBr₃ film was deposited using the sequential thermal evaporation by Hua et al. [118], and they found a new epitaxially-stabilized tetragonal phase for controlling the electronic properties using in situ real-time diffraction techniques. Huo et al. prepared single CsPbBr₃ NPLs and single-photon emission without blinking is observed using these NPLs [119]. Gao et al. proposed a facile colloidal method to obtain CsPbBr₃ nanoribbons and deep-blue light emission based on this material is studied [120].

As shown in this section, AIMHP 2D nanomaterials represent an exciting new class of semiconductor nanomaterials. Their excellent absorption and emission properties and facile synthesis make them a promising material for many applications. However, there is still a lot of work to be done on how to obtain and utilize the strong QCE in 2D nanomaterials compared to 0D and 1D AIMHP nanomaterials. In Table 1, we summarized the compositions, shapes and optical properties of CsPbX₃ nanostructured material.

3 Optical properties of all-inorganic metal halide perovskite nanomaterials

In the second part, we summarized the advances in the synthesis of AIMHP nanomaterials based on their different dimensions. At the same time, we also introduced in detail the material preparation method, structure, morphology, size and related optimizati the material properties, especially the photoelectric properties. In this part, we will further summarize the excellent optical properties of AIMHP nanomaterials relative to bulk materials, mainly including the following three aspects:

3.1 Strong quantum confinement effect

As is known to all, one of the biggest characteristics of nanomaterials is that the QCE in the optical properties of materials can be observed when the size of an AIMHP is too small to be comparable to the Bohr radius of excitons. Excitons are confined in all three spatial dimensions, which results in a transition from continuous to discrete energy levels. Theoretical calculation shows that the exciton Bohr radius is about 7 nm of all-inorganic CsPbBr₃ PNCs; the QCE is quite prominent in CsPbBr₃ perovskite NCs when its size becomes comparable with the exciton Bohr radius. For instance, the emission of CsPbBr₃ perovskite NCs can be truly tuned from around 2.7 eV to 2.4 eV with the size changing from 4 nm to 12 nm which is in good agreement with the theoretical calculation [61, 121, 122]. A large number of experimental results show that the QCE is also observed in 1D [123] and 2D [104, 113] AIMHP materials. The QCE provides a way to tune the emission of semiconductors, which results in potential for various light-emitting applications.

3.2 Wide range of adjustable optical properties

Carry on the discussion in the previous section, the bandgap and optical absorption (emission) properties could be tuned by changing the size of the AIMHP nanomaterials with the decrease of the crystal size. Kovalenko and co-workers first fabricated the CsPbX₃ structure with exceptionally tunable optical properties [38]. Compared to other low dimensional nanostructured materials, an attractive feature of AIMHP is facile tunable emission throughout the whole visible range, achieved through controlling the material composition, dimensions and structure. The emission of all inorganic-perovskite CsPbX₃ (X=Cl, Br, I, or their mixture), including QDs, QWs and NPLs, can be well-tuned from 400 nm (blue) to 700 nm (red), which covers the whole visible region [23, 124, 125]. Even, the emission of perovskite can be further tuned to the near-infrared or ultraviolet region through particle replacement method and new device structure [126].

3.3 High quantum yield efficiency

Quantum efficiency, defined as the ratio of the number of converted photons to absorbed photons, is one of the most crucial properties for light emitters [127–136]. High quantum efficiency usually signifies that most of the absorbed photons were converted through radiative recombination processes rather than non-radiative recombination processes. Perovskites are regarded as excellent light emitters due to their large absorption coefficient and high quantum efficiency [137]. High quantum efficiencies up to 96.9% have been reported in both all-inorganic CsPbX₃ and organic-inorganic methylammonium lead halide perovskite nanocrystals without any further surface treatment [138]. The high quantum efficiency in perovskite is the result of a clear bandgap with negligible charge-trapping states, which greatly promote the exciton radiative recombination efficiency. With their high quantum efficiency, perovskites are promising alternatives for light-emitting applications [139, 140].

4 Applications of all-inorganic metal halide perovskite nanomaterials

AIMHP nanomaterials have attracted great interest in recent years due to their good device performance with higher thermal stability than that of OMHP and HOIMHP. These CsPbBr₃ nanowires can be potentially used for nanoscale photonic, electronic, and optoelectronic devices, including SCs, LEDs, lasers, PDs, single-photon quantum sources (SPQS), and so on.

4.1 Solar cells

From the first report in 2015 to now, the PCE of CsPbX₃-based perovskite SCs (PSCs) has abruptly increased from 2.9% to 23.7% with much-enhanced stability [141–143]. High-efficiency PSCs were realized by tuning the bandgap and stabilizing the black perovskite phase of CsPbI₂Br at lower temperatures. The device can be realized 9.8% power conversion efficiency (PCE) and over 5% stabilized power output [144]. Zhou et al. made inverse opal perovskite SCs based on the slow-photon effect of carbon QD sensitized CsPbBr₃ [145]. Compared with planar CsPbBr₃, the perovskite SCs PCE can be up to 8.29% and incident photon-to-electron conversion efficiency can be up to 76.9%. It is worth mentioning that QD modified bifacial PSCs were reported by Li et al. [146]. The SC without encapsulation retains around 95% of the initial efficiency at 60% room temperature over a period of 1000 h. Tang et al. studied the effect of annealing temperature on CsPbBr₃ SCs, which show excellent stability in ambient air with the humidity up to 70% [147].

On the basis of the previous research, the scientists further adopt the material and device optimization techniques to improve the characteristics of SCs. For instance, interface engineering (self-passivation and electron transporting layer) and defect-engineering were introduced to the stability and QCE of the PSCs [148–152]. Scientists adopt a new precursor pair (cesium acetate/hydrogen lead trihalide and DMAI/DMAPbIx) or single-source thermal evaporation to fabricate high-quality CsPbX₃ perovskite film and to improve the stability of the device [153–155]. Nanocrystalline controlled synthesis methods were widely used methods to improve the properties of materials and devices [156–158]. Besides, the study found that designing new inverted structure was critical to realize efficient and stable PSCs. The results showed that the devices based on new structure exhibit improved optoelectronic properties, more favorable interfacial energetics, and reduced recombination due to an improved trap passivation effect [159, 160].

4.2 Light emitting diodes

In 2015, Song et al. fabricated tunable LEDs based on all-inorganic perovskite CsPbX₃ (X=Cl, Br, I) QDs for the first time [161]. The external quantum efficiencies (EQE) of the blue, orange, and green LEDs were 0.07%, 0.09%, and 0.12%, respectively. This study showed that fully inorganic perovskite can be used as the emitter of LEDs devices, although the EQE is still relatively low. Since then, scientists have taken various measures to improve the stability [54, 162–164], quantum efficiency [165–167] and color purity [168] of materials and devices. In the past five years, the performances (EQE, current efficiency, power efficiency, luminance or brightness, lifetime and voltage) of LEDs based on AIMHP have been greatly enhanced [169–173]. Currently, the highest EQE of all-inorganic LEDs is above 20% [174], which is comparable to the state-of-the-art organic LEDs. The results also showed that the operational stability of the light-emitting devices based on CsPbBr₃ QDs was 36 times higher because the surface ligand density of the corresponding QDs was lower.

So, the scientists further adopt the material and device optimization techniques to improve the characteristics of LEDs [175–180]. For example, interface engineering (interfacial passivation strategy) was introduced to prompt the efficiency and stability of perovskite QD LEDs [175–178]. Song et al. employed a tetrabutylammonium bromide to reduce nonradiative defects of CsPbBr₃ and it results in further promotion of electroluminescence performance of LED [175]. A two-step ligand-exchange strategy was developed by Shan et al. to fabricate all-inorganic perovskite CsPbX₃ (X=Br, Cl) QDs with halide-ion-pair ligands. Green and blue LEDs made from the halide-ion-pair-capped QDs exhibit high EQE compared with the untreated QDs [176]. Xu et al. proposed a bilateral passivation strategy through passivating both top and bottom interfaces of CsPbBr₃ QD film, which has drastically enhanced the efficiency and stability of perovskite LEDs with a maximum EQE of 18.7% and current efficiency of 75cdA^–1 [178]. Besides, device engineering technology was also used to improve LED efficiency and performance [177–180]. Some strategies such as improving the hole injection, enhancing the electron injection, increasing the charge balance and decreasing the charge leakage, and so on have been adopted to promoting efficiency and stability of perovskite LEDs.

4.3 Lasing

The emission wavelength tunability demonstrated in perovskite materials was an attractive property for nanoscale lasers. Cesium lead halides offer a robust alternative without sacrificing emission tunability or ease of synthesis. Eaton et al. first reported all-inorganic CsPbX₃ NW lasers in 2016, as shown in Fig. 4 [81]. The Fabry–Perot (F–P) perovskite NWs lasing displayed an excellent performance with a threshold of ~5 μJ/cm² and maximum quality factor (MQF) of ~1009±5 when pumped by 400 nm pulsed source. Remarkably, the lasing can be maintained for over 1 h when persist upon exposure to ambient atmosphere, showing much better performance than the hybrid perovskite NW lasers. Fu et al. reported a single-crystal CsPbX₃ NWs for lasing [181]. They synthesized CsPbBr₃ NWs with different lengths ranging from 5–21 μm and realized either single or multiple lasing with thresholds ranging from 2.8 μJ/cm² to 9 μJ/cm². The NW laser can output stable lasing emissions for longer than 8 h using continuous pumping. Park et al. synthesized the CsPbX₃ NWs with lengths of about 2–15 μm by using the CVD method and realized the lasers with low thresholds of 6, 3, and 7 μJ/cm², with MQFs of 1200, 1300, and 1400 for CsPbI₃, CsPbBr₃ and CsPbCl₃, respectively [182]. Zhang et al. comprehensively investigated the strong exciton-photon coupling in micro/nanowires system with low-threshold polariton lasing at room temperature [183]. Large-area CsPbX₃ NW laser arrays with lengths of ~10–20 μm were achieved by vapor growth method with a low threshold of ~4 μJ/cm² and high MQF of ~2256 [184]. Zhu et al. further realized the CW lasing in CsPbBr₃ NWs with a threshold of ~6 kW/cm² [185]. Wang et al. reported the multiphoton-pumped lasing from CsPbX₃ nanorods with thresholds of ~0.6 and 1.7 mJ/cm² under excitations of 800 and 1200 nm with 80 fs and 1 kHz [186]. Meanwhile, Hu et al. demonstrated F-P lasing in CsPbBr₃ microcubes with high MQF of 1150 under optical excitation (800 nm, 35 fs, 1 kHz) [187].

Temperature-dependent lasers based on AILHP have been studied in depth, because nanostructured lasers are very sensitive to temperature [188–191]. At the same time, scientists using new material system and material structure or device engineering have been used to improve the detector’s properties [192–200]. Pushkarev et al. reported a novel approach to fabricate high-quality CsPbBr₃ nanolasers obtained by rapid precipitation from dimethyl sulfoxide solution sprayed onto hydrophobic substrates at ambient conditions [193]. In-plane self-assembly CsPbBr₃ NWs and CsPbBr₃ QDs embedded in silica sphere were used to improve the stability and performance of CsPbBr₃ nanolasers [194, 195]. In addition, inorganic and hybrid perovskites have been exploited to boost the external luminescence efficiency of lasers [197–199]. Recently, Polushkin et al. provided a comprehensive analysis of single-particle perovskite lasers with various compositions and shapes [200].

4.4 Photodetectors

PDs have many important applications including imaging, optical communication, remote control, chemical/biological sensing and so on. For an ideal PD, it is necessary to have high spectral selectivity, high signal-to-noise ratio, high sensitivity, high stability, and high speed. Dong et al. for the first time demonstrated the visible light PDs with synergetic effect of preferred-orientation and plasmonic effect based on the all-inorganic perovskite CsPbBr₃ NCs [201]. And, the photocurrentwas increased more than 200% after introducing the Au NCs into the device, which was contributed to the near field enhancement effect between CsPbBr₃ NCs and Au NCs. Their results suggested that all-inorganic perovskites are promising semiconductors for high-performance solution-processed PDs, as shown in Fig. 5. Next year, low-voltage PDs with high responsivity based on all-inorganic scattered CsPbBr₃ nanoplatelets are fabricated [202]. The photoresponsivity of PDs based on these nanoplatelets is as high as 34 A·W^–1, with an external driven voltage of 1.5 V under illumination using a 442 nm laser. To improve the responsivity, a planar structure perovskite PDs based on the CsPbBr₃ nanosheet/CNT composite films are constructed and exhibit both high light-harvesting and high conductivity [203]. A high EQE of 7488% and high responsivity of 31.1 A·W^–1 under a bias of 10 V are achieved.

In addition to the 0D and 2D CsPbBr₃ nanomaterials, 1D AILHP was widely used to prepare optical detectors with high stability and high detection rate [204–210]. Then, superior PDs based on a 1D CsPbI₃ nanorods were constructed, with a responsivity of 2.92×10³ A·W^–1, an ultrafast response time of 0.05 ms and a detectivity approached up to 5.17×10¹³ Jones [204]. Stabilized Sn-doped CsPbI₃ nanobelts with satisfied stability for up to 15 days when maintained under air condition were successfully synthesized. The as-constructed PDs based on the CsPb_0.922Sn_0.078I₃ nanobelts displayed an ultrahigh detectivity of up to 6.43×10¹³ Jones [205]. A sensitive deep ultraviolet (DUV) light PD based Cs₃Cu₂I₅ was reported [200]. The PD exhibited pronounced sensitivity to both DUV and UV light illumination with response speeds of 26.2/49.9 ms for rise/fall time.

Self-powered photodetectors (SPPDs) with no external power sources, high-sensitivity and fast response speed is an important type of PDs. Self-powered all-perovskite PDs with high detectivity, high-sensitivity and fast response speed were reported by different research groups [211–215]. At the same time, the scientists further adopted the material and device optimization techniques such as interfacial engineering, inverse structure, core-shell technique, vertical Schottky junction, and fast interfacial charge transfer layers to improve the detector’s properties [216–220]. The experimental data showed that the enhanced device performance is attributed to the improved crystallinity and less surface defects of AIMHP nanomaterials.

4.5 Applications in other optoelectronic devices

In addition to the nanoscale photonic and optoelectronic devices, including SCs, LEDs, lasers and PDs, AIMHP nanomaterials were also widely used in other devices. A facile design of hybrid phototransistors with an outstanding responsivity of 4.9×10⁶A·W^–1, fast response of 0.45 s/0.55 s, and long-term stability of 200 h in ambient based on the CsPbBr₃ thin film is reported [221]. Polarization-sensitive light sources based on well-aligned CsPbBr₃ and CsPbCl₃ NWs were reported [222]. Recently, a field-effect transistor (FET) has been fabricated using the all-inorganic CsPbBr₃ NCs [223, 224]. The CsPbBr₃-NC transistors exhibit a clean unipolar transport characteristic in a p-type mode featuring well-defined linear and saturation regimes.

Except for the conventional optoelectronic device described above, AIMHP has been employed as next-generation light sources, such as SPQS [224, 225]. The CsPbX₃ (X=Cl/Br) NCs exhibit stable, narrow-band emission with suppressed blinking and small spectral diffusion at low-temperature. Photon demonstrates unambiguously nonclassical single-photon emission with radiative decay on the order of 250 ps, representing a significant acceleration compared to other common quantum emitters.

5 Conclusions and outlook

In summary, taking all-inorganic perovskite CsPbX₃ (X=Cl, Br, I or mixture of halides) nanomaterials as representative, we provide an overview of the up-to-date developments in synthesis, attractive optical properties and related emerging applications of AIMHP nanomaterials. First of all, we can see that the material compositions, dimensionality, morphologies and structures of AIMHP nanomaterials are an important factor affecting the optical properties and performance of the device. Besides that, as shown in the paper, through adopting the material and device optimization techniques such as interface engineering (self-passivation and electron transporting layer), defect engineering, and device engineering (inverting device structure, enhancing the hole and the electron injection, increasing the charge balance, decreasing the charge leakage and so on) others in constructing optoelectric devices, the performance could be improved remarkably. Therefore, continuing to study the effects of material and device optimization techniques on nanostructured light-emitting devices from the microscopic perspective and understanding the correlation between the properties of nanostructured devices in depth is crucial. Even though this progress in the improvement of the stabilities and performances of AIMHP nanomaterials and devices is very encouraging, there are several shortcomings and challenges that stand in the way of commercialization. The following aspects are critical to improving the performance of devices.

1) Understanding of the physics in low-dimensional perovskites

Since tremendous optoelectronic applications have been demonstrated, the investigations focusing on fundamental properties of low-dimensional perovskites have not attracted much attention. With the reduced dimensions, some inherent natures like band structure and photon transport will behave differently. However, the study on this aspect is limited and more efforts should be devoted to further exploration. In addition, the low dimensionality could also bring about confined charge transport in the selected directions, leading to unique electrical properties such as 2D electron gas, which is the basis for field-effect devices. However, these fundamental investigations lag far behind the application. We have drawn more attention in the near future [226–228].

2) Precise control of the size and dimensionality

As one of the most valuable merits with reduced dimensionality, size and dimensional control for various bandgaps attract tremendous attention. Nowadays, although some groups can manipulate the perovskites with size and shape control to some degree, most synthesis methods for low-dimensional perovskites are trial-and-error, without a precise regulation. We are inquisitive whether this approach can be utilized as the guidelines for the synthesis of perovskites with accurate structures and dimensions we desire. Based on these, more explorations of in-depth physical mechanism and wide applications will be duly concomitant [229, 230].

3) Pb-free metal halide NCs

Concerning the environmental issues, lead-free IHPs are necessary and more appealing. As we have shown in part in this article, colloidal metal halide NCs containing tin (Sn), germanium (Ge), indium (In), bismuth (Bi), and antimony (Sb) can be explored as a replacement for Pb halides. The development of environmentally benign lead-free halide perovskites with comparable excellent features and exploration of their fundamental optical and electronic properties and environmental stability are interesting, such as Cs₂AgBiX₆, Cs₃Bi₂X₉, Cs₃Sb₂X₉, CsEuCl₃ and other analogues [231, 232].

References

[1] H. Tsai, W. Nie, J. C. Blancon, C. C. Stoumpos, R. Asadpour, B. Harutyunyan, A. J. Neukirch, R. Verduzco, J. J. Crochet, S. Tretiak, L. Pedesseau, J. Even, M. A. Alam, G. Gupta, J. Lou, P. M. Ajayan, M. J. Bedzyk, M. G. Kanatzidis, and A. D. Mohite, High-efficiency two-dimensional Ruddlesden-popper perovskite solar cells, Nature 536(7616), 312 (2016)

[2] Y. Han, H. Zhao, C. Y. Duan, S. M. Yang, Z. Yang, Z. K. Liu, and S. Z. Liu, Controlled n-doping in air-stable CsPbI₂Br perovskite solar cells with a record efficiency of 16.79%, Adv. Funct. Mater. 30(12), 1909972 (2020)

[3] Z. Z. Li, F. G. Zhou, Q. Wang, L. M. Ding, and Z. W. Jin, Approaches for thermodynamically stabilized CsPbI₃ solar cells, Nano Energy 71, 104634 (2020)

[4] J. Xing, F. Yan, Y. W. Zhao, S. Chen, H. K. Yu, Q. Zhang, R. G. Zeng, X. W. Demir, X. S. Sun, and Q. H. Xiong, High-efficiency light-emitting diodes of organometal halide perovskite amorphous nanoparticles, ACS Nano 10(7), 6623 (2016)

[5] K. B. Lin, J. Xing, L. N. Quan, F. P. G. Arquer, X. W. Gong, J. X. Lu, L. Q. Xie, W. J. Zhao, D. Zhang, C. Z. Yan, W. Q. Li, X. Y. Liu, Y. Lu, J. Kirman, E. H. Sargent, Q. H. Xiong, and Z. H. Wei, Perovskite light-emitting diodes with external quantum efficiency exceeding 20 percent, Nature 562(7726), 245 (2018)

[6] H. Cho, Y. H. Kim, C. Wolf, H. D. Lee, and T. W. Lee, Improving the stability of metal halide perovskite materials and light-emitting diodes, Adv. Mater. 30(42), 1704587 (2018)

[7] H. M. Zhu, Y. P. Fu, F. Meng, X. X. Wu, Z. Z. Gong, Q. Ding, M. V. Gustafsson, M. T. Trinh, S. Jin, and X. Y. Zhu, Lead halide perovskite nanowire lasers with low lasing thresholds and high quality factors, Nat. Mater. 14(6), 636 (2015)

[8] N. Zhang, Y. B. Fan, K. Y. Wang, Z. Y. Gu, Y. H. Wang, L. Ge, S. M. Xiao, and Q. H. Song, All-optical control of lead halide perovskite microlasers, Nat. Commun. 10(1), 1770 (2019)

[9] J. Chen, W. N. Du, J. W. Shi, M. L. Li, Y. Wang, Q. Zhang, and X. F. Liu, Perovskite quantum dot lasers, InfoMat 2(1), 170 (2019)

[10] X. H. Cheng, Y. Yuan, L. Jing, T. L. Zhou, Z. X. Li, Z. W. Peng, Q. Yao, J. Zhang, and J. X. Ding, Nucleation-controlled growth of superior long oriented CsPbBr₃ microrod single crystals for high detectivity photodetectors, J. Mater. Chem. C 7(45), 14188 (2019)

[11] J. G. Feng, C. Gong, H. F. Gao, W. Wen, Y. J. Gong, X. Jiang, B. Zhang, Y. Wu, Y. Wu, H. Fu, L. Jiang, and X. Zhang, Single-crystalline layered metal-halide perovskite nanowires for ultrasensitive photodetectors, Nat Electron 1(7), 404 (2018)

[12] J. P. Deng, J. L. Li, Z. Yang, and M. Q. Wang, All-inorganic lead halide perovskites: A promising choice for photovoltaics and detectors, J. Mater. Chem. C 7(40), 12415 (2019)

[13] W. Nie, J. C. Blancon, A. J. Neukirch, K. Appavoo, H. Tsai, M. Chhowalla, M. A. Alam, M. Y. Sfeir, C. Katan, J. Even, S. Tretiak, J. J. Crochet, G. Gupta, and A. D. Mohite, Light-activated photocurrent degradation and self-healing in perovskite solar cell, Nat. Commun. 7(1), 11574 (2016)

[14] G. Divitini, S. Cacovich, F. Matteocci, L. Cinà, A. Di Carlo, and C. Ducati, In situ observation of heat-induced degradation of perovskite solar cells, Nat. Energy 1(2), 15012 (2016)

[15] Z. Li, M. Yang, J. S. Park, S. H. Wei, J. J. Berry, and K. Zhu, Stabilizing perovskite structures by tuning tolerance factor: formation of formamidinium and cesium lead iodide solid-state alloys, Chem. Mater. 28(1), 284 (2016)

[16] S. Yang, Y. Wang, P. Liu, Y. B. Cheng, H. J. Zhao, and H. G. Yang, Functionalization of perovskite thin films with moisture-tolerant molecules, Nat. Energy 1(2), 15016 (2016)

[17] Y. C. Zhao, J. Wei, H. Li, Y. Yan, W. K. Zhou, D. P. Yu, and Q. A. Zhao, Polymer scaffold for self-healing perovskite solar cells, Nat. Commun. 7(1), 10228 (2016)

[18] J. B. You, L. Meng, T. B. Song, T. F. Guo, Y. M. Yang, W. H. Chang, Z. R. Hong, H. J. Chen, H. P. Zhou, Q. Chen, Y. S. Liu, N. D. Marco, and Y. Yang, Improved air stability of perovskite solar cells via solution-processed metal oxide transport layers, Nat. Nanotechnol. 11(1), 75 (2016)

[19] L. Protesescu, S. Yakunin, I. Maryna, M. I. Bodnarchuk, F. Krieg, R. Caputo, C. H. Hendon, R. X. Yang, A. Walsh, and M. V. Kovalenko, Nanocrystals of cesium lead halide perovskites (CsPbX₃, X=Cl, Br, and I): Novel optoelectronic materials showing bright emission with wide color gamut, Nano Lett. 15(6), 3692 (2015)

[20] D. Wang, W. J. Li, Z. B. Du, G. D. Li, W. H. Sun, J. H. Wu, and L. Z. Zhang, CoBr₂-doping-induced efficiency improvement of CsPbBr₃ planar perovskite solar cells, J. Mater. Chem. C 8(5), 1649 (2020)

[21] W. Z. Lv, L. Li, M. G. Li, L. G. Xu, W. Huang, and R. F. Chen, Self-assembly of completely inorganic perovskite nanocrystals with improved stability by anchoring on kaolinite lamellae, Adv. Opt. Mater. 8(6), 1901485 (2020)

[22] J. L. Duan, Y. D. Wang, X. Y. Yang, and Q. W. Tang, Alkyl-chain-regulated charge transfer in fluorescent inorganic CsPbBr₃ perovskite solar cells, Angew. Chem. Int. Ed. 59(11), 4391 (2020)

[23] S. T. Ha, R. Su, J. Xing, Q. Zhang, and Q. H. Xiong, Metal halide perovskite nanomaterials: Synthesis and applications, Chem. Sci. 8(4), 2522 (2017)

[24] D. D. Zhang, S. W. Eaton, Y. Yu, L. T. Dou, and P. D. Yang, Solution-phase synthesis of cesium lead halide perovskite nanowires, J. Am. Chem. Soc. 137(29), 9230 (2015)

[25] D. D. Zhang, Y. Yu, Y. Bekenstein, A. B. Wong, A. P. Alivisatos, and P. D. Yang, Ultrathin colloidal cesium lead halide perovskite nanowires, J. Am. Chem. Soc. 138(40), 13155 (2016)

[26] M. Imran, F. Di Stasio, Z. Dang, C. Canale, A. H. Khan, J. Shamsi, R. Brescia, M. Prato, and L. Manna, Colloidal synthesis of strongly fluorescent CsPbBr₃ nanowires with width tunable down to the quantum confinement regime, Chem. Mater. 28(18), 6450 (2016)

[27] J. Chen, Y. P. Fu, L. Samad, L. N. Dang, Y. H. Zhao, S. H. Shen, L. J. Guo, and S. Jin, Vapor-phase epitaxial growth of aligned nanowire networks of cesium lead halide perovskites (CsPbX₃, X= Cl, Br, I), Nano Lett. 17(1), 460 (2017)

[28] Y. Bekenstein, B. A. Koscher, S. W. Eaton, P. Yang, and A. P. Alivisatos, Highly luminescent colloidal nanoplates of perovskite cesium lead halide and their oriented assemblies, J. Am. Chem. Soc. 137(51), 16008 (2015)

[29] J. Shamsi, Z. Y. Dang, P. Bianchini, C. Canale, F. Di Stasio, R. Brescia, M. Prato, and L. Manna, Colloidal synthesis of quantum confined single crystal CsPbBr₃ nanosheets with lateral size control up to the micrometer range, J. Am. Chem. Soc. 138(23), 7240 (2016)

[30] J. Chen, D. Morrow, Y. P. Fu, W. H. Zheng, Y. Z. Zhao, L. N. Dang, M. J. Stolt, D. D. Kohler, X. X. Wang, K. J. Czech, M. P. Hautzinger, S. H. Shen, L. J. Guo, A. L. Pan, J. C. Wright, and S. Jin, Single-crystal thin films of cesium lead bromide perovskite epitaxially grown on metal oxide perovskite (SrTiO₃), J. Am. Chem. Soc. 139(38), 13525 (2017)

[31] A. Dutta, R. K. Behera, P. Pal, S. Baitalik, and N. Pradhan, Near-unity photoluminescence quantum efficiency for all CsPbX₃ (X=Cl, Br, and I) perovskite nanocrystals: a generic synthesis approach, Angew. Chem. Int. Ed. 131(17), 5608 (2019)

[32] G. C. Xing, B. Wu, X. Y. Wu, M. J. Li, B. Du, Q. Wei, J. Guo, E. K. L. Yeow, T. C. Sum, and W. Huang, Transcending the slow bimolecular recombination in lead-halide perovskites for electroluminescence, Nat. Commun. 8(1), 14558 (2017)

[33] J. R. Zhang, G. Hodes, Z. W. Jin, and S. Z. Liu, All-inorganic CsPbX₃ perovskite solar cells: Progress and prospects, Angew. Chem. Int. Ed. 58(44), 15596 (2019)

[34] L. Huang, Q. G. Gao, L. D. Sun, H. Dong, S. Shi, T. Cai, Q. Liao, and C. H. Yan, Composition-graded cesium lead halide perovskite nanowires with tunable dual-color lasing performance, Adv. Mater. 30(27), 1800596 (2018)

[35] H. W. Huang, M. Liu, J. Li, L. H. Luo, J. T. Zhao, Z. L. Luo, X. P. Wang, Z. Z. Ye, H. P. He, and J. Zeng, Atomically thin cesium lead bromide perovskite quantum wires with high luminescence, Nanoscale 9(1), 104 (2017)

[36] K. Wang, Z. W. Jin, H. Liang, H. Bian, D. L. Bai, H. R. Wang, J. R. Zhang, Q. Wang, and S. Z. Liu, All-inorganic cesium lead iodide perovskite solar cells with stabilized efficiency beyond 15%, Nat. Commun. 9(1), 4544 (2018)

[37] Y. Z. Hu, W. C. Zhang, Y. Ye, Z. Y. Zhao, and C. Liu, Femtosecond-laser-induced precipitation of CsPbBr₃ perovskite nanocrystals in glasses for solar spectral conversion, ACS Appl. Nano Mater. 3(1), 850 (2020)

[38] A. P. Schlaus, M. S. Spencer, K. Miyata, F. Liu, X. X. Wang, I. Datta, M. Lipson, A. L. Pan, and X. Y. Zhu, How lasing happens in CsPbBr₃ perovskite nanowires, Nat. Commun. 10(1), 265 (2019)

[39] M. J. Adams, D. Jevtics, M. J. Strain, I. D. Henning, and A. Hurtado, High-frequency dynamics of evanescently-coupled nanowire lasers, Sci. Rep. 9(1), 6126 (2019)

[40] Z. G. Xiao, R. A. Kerner, L. F. Zhao, N. L. Tran, K. M. Lee, T. W. Koh, G. D. Scholes, and B. P. Rand, Efficient perovskite light-emitting diodes featuring nanometre-sized crystallites, Nat. Photonics 11(2), 108 (2017)

[41] Z. C. Li, Z. M. Chen, Y. C. Yang, Q. F. Xue, H. L. Yip, and Y. Cao, Modulation of recombination zone position for quasi-two-dimensional blue perovskite light-emitting diodes with efficiency exceeding 5%, Nat. Commun. 10(1), 1027 (2019)

[42] Q. S. Chen, J. Wu, X. Y. Ou, B. L. Huang, J. Almutlaq, A. A. Zhumekenov, X. W. Guan, S. Y. Han, L. L. Liang, Z. G. Yi, J. Li, X. J. Xie, Y. Wang, Y. Li, D. Y. Fan, B. L. T. Daniel, H. A. Angelo, O. F. Mohammed, O. M. Bakr, T. Wu, M. Bettinelli, H. H. Yang, W. Huang, and X. G. Liu, All-inorganic perovskite nanocrystal scintillators, Nature 561(7721), 88 (2018)

[43] A. Waleed, M. M. Tavakoli, L. Gu, S. Hussain, D. Zhang, S. Poddar, Z. Wang, R. Zhang, and Z. Fan, All inorganic cesium lead iodide perovskite nanowires with stabilized cubic phase at room temperature and nanowire array-based photodetectors, Nano Lett. 17(8), 4951 (2017)

[44] T. Chiba, Y. Hayashi, H. Ebe, K. Hoshi, J. Sato, S. Sato, Y. J. Pu, S. Ohisa, and J. J. Kido, Anion-exchange red perovskite quantum dots with ammonium iodine salts for highly efficient light-emitting devices, Nat. Photonics 12(11), 681 (2018)

[45] Q. S. Sun, C. L. Ni, Y. C. Yu, S. Attique, S. Wei, Z. Ci, J. Wang, and S. Yang, Design principle of all-inorganic halide perovskite-related nanocrystals, J. Mater. Chem. C 6(46), 12484 (2018)

[46] T. Chen, Y. Q. Xu, Z. X. Xie, W. H. Jiang, L. J. Wang, and W. Jiang, Ionic liquid assisted preparation and modulation of the photoluminescence kinetics for highly efficient CsPbX₃ nanocrystals with improved stability, Nanoscale 12(17), 9569 (2020)

[47] B. Yang, J. S. Chen, F. Hong, X. Mao, K. B. Zheng, S. Q. Yang, Y. J. Li, T. Pullerits, W. Q. Deng, and K. L. Han, Lead-free, air-stable all-inorganic cesium bismuth halide perovskite nanocrystals, Angew. Chem. Int. Ed. 56(41), 12471 (2017)

[48] Z. H. Shen, S. L. Zhao, D. D. Song, Z. Xu, B. Qiao, P. J. Song, Q. Y. Bai, J. Y. Cao, G. Q. Zhang, and W. Swelm, Improving the quality and luminescence performance of all-inorganic perovskite nanomaterials for light-emitting devices by surface engineering, Small 16(26), 1907089 (2020)

[49] J. T. Gan, J. X. He, R. L. Z. Hoye, A. Mavlonov, F. Raziq, J. L. Macmanusdriscoll, X. Q. Wu, S. Li, X. T. Zu, Y. Q. Zhan, X. Y. Zhang, and L. Qiao, α-CsPbI₃ colloidal quantum dots: Synthesis, photodynamics and photovoltaic applications, ACS Energy Lett. 4(6), 1308 (2019)

[50] P. C. Zhu and J. Zhu, Low-dimensional metal halide perovskites and related optoelectronic applications, InfoMat 2(2), 341 (2020)

[51] X. He, Y. Qiu, and S. Yang, Fully-inorganic trihalide perovskite nanocrystals: A new research frontier of optoelectronic materials, Adv. Mater. 29(32), 1700775 (2017)

[52] H. Huang, M. I. Bodnarchuk, S. V. Kershaw, M. V. Kovalenko, and A. L. Rogach, Lead halide perovskite nanocrystals in the research spotlight: Stability and defect tolerance, ACS Energy Lett. 2(9), 2071 (2017)

[53] L. S. Rao, Y. Tang, C. J. Song, K. Xu, E. T. Vickers, S. Bonabi Naghadeh, X. R. Ding, Z. T. Li, and J. Z. Zhang, Polar-solvent-free synthesis of highly photoluminescent and stable CsPbBr₃ nanocrystals with controlled shape and size by ultrasonication, Chem. Mater. 31(2), 365 (2019)

[54] A. Swarnkar, R. Chulliyil, V. K. Ravi, M. Irfanullah, A. Chowdhury, and A. Nag, Colloidal CsPbBr₃ perovskite nanocrystals: luminescence beyond traditional quantum dots, Angew. Chem. Int. Ed. 54(51), 15424 (2015)

[55] G. P. Li, H. Wang, T. Zhang, L. Mi, Y. Zhang, Z. Zhang, W. Zhang, and Y. Jiang, Solvent-polarity-engineered controllable synthesis of highly fluorescent cesium lead halide perovskite quantum dots and their use in white light-emitting diodes, Adv. Funct. Mater. 26(46), 8478 (2016)

[56] W. Zhang, G. E. Eperon, and H. J. Snaith, Metal halide perovskites for energy applications, Nat. Energy 1(6), 16048 (2016)

[57] Y. Tong, E. Bladt, M. F. Aygüler, A. Manzi, K. Z. Milowska, V. A. Hintermayr, P. Docampo, S. Bals, A. S. Urban, L. Polavarapu, and J. Feldmann, Highly luminescent cesium lead halide perovskite nanocrystals with tunable composition and thickness by ultrasonication, Angew. Chem. Int. Ed. 55(44), 13887 (2016)

[58] L. Protesescu, S. Yakunin, O. Nazarenko, D. Dirin, and M. Kovalenko, Low-cost synthesis of highly luminescent colloidal lead halide perovskite nanocrystals by wet ball milling, ACS Appl. Nano Mater. 1(3), 1300 (2018)

[59] A. H. Slavney, T. Hu, A. M. Lindenberg, and H. I. Karunadasa, A bismuth-halide double perovskite with long carrier recombination lifetime for photovoltaic applications, J. Am. Chem. Soc. 138(7), 2138 (2016)

[60] G. Nedelcu, L. Protesescu, S. Yakunin, M. I. Bodnarchuk, M. J. Grotevent, and M. V. Kovalenko, Fast anion-exchange in highly luminescent nanocrystals of cesium lead halide perovskites (CsPbX₃, X = Cl, Br, I), Nano Lett. 15(8), 5635 (2015)

[61] Q. A. Akkerman, V. D’Innocenzo, S. Accornero, A. Scarpellini, A. Petrozza, M. Prato, and L. Manna, Tuning the optical properties of cesium lead halide perovskite nanocrystals by anion exchange reactions, J. Am. Chem. Soc. 137(32), 10276 (2015)

[62] T. C. Jellicoe, J. M. Richter, H. F. J. Glass, M. Tabachnyk, R. Brady, S. E. Dutton, A. Rao, R. H. Friend, D. Credgington, N. C. Greenham, and M. L. Böhm, Synthesis and optical properties of lead-free cesium tin halide perovskite nanocrystals, J. Am. Chem. Soc. 138(9), 2941 (2016)

[63] X. M. Li, Y. Wu, S. L. Zhang, B. Cai, Y. Gu, J. Z. Song, and H. B. Zeng, CsPbX₃ quantum dots for lighting and displays: Room-temperature synthesis, photoluminescence superiorities, underlying origins and white light-emitting diodes, Adv. Funct. Mater. 26(15), 2435 (2016)

[64] S. B. Sun, D. Yuan, Y. Xu, A. F. Wang, and Z. T. Deng, Ligand-mediated synthesis of shape-controlled cesium lead halide perovskite nanocrystals via reprecipitation process at room temperature, ACS Nano 10(3), 3648 (2016)

[65] J. De Roo, M. Ibáñez, P. Geiregat, G. Nedelcu, W. Walravens, J. Maes, J. C. Martins, I. Van Driessche, M. V. Kovalenko, and Z. Hens, Highly dynamic ligand binding and light absorption coefficient of cesium lead bromide perovskite nanocrystals, ACS Nano 10(2), 2071 (2016)

[66] A. Swarnkar, A. R. Marshall, E. M. Sanehira, B. D. Chernomordik, D. T. Moore, J. A. Christians, T. Chakrabarti, and J. M. Luther, Quantum dot-induced phase stabilization of a-CsPbI₃ perovskite for high-efficiency photovoltaics, Science 354(6308), 92 (2016)

[67] S. Ye, M. J. Zhao, J. Song, and J. Qu, Controllable emission bands and morphologies of high-quality CsPbX₃ perovskite nanocrystals prepared in octane, Nano Res. 11(9), 4654 (2018)

[68] H. G. Lu, Y. Tang, L. S. Rao, Z. T. Li, X. R. Ding, C. J. Song, and B. H. Yu, Investigating the transformation of CsPbBr₃ nanocrystals into highly stable CsPbBr₃/Cs₄PbBr₆ nanocrystals using ethyl acetate in a microchannel reactor, Nanotechnology 30(29), 295603 (2019)

[69] X. S. Tang, J. Yang, S. Q. Li, W. W. Chen, Z. P. Hu, and J. Qiu, CsPbBr₃/CdS core/shell structure quantum dots for inverted light-emitting diodes application, Front. Chem. 7, 499 (2019)

[70] L. J. Chen, L. Wan, X. D. Li, W. X. Zhang, S. Fu, Y. M. Wang, S. Li, H. Q. Wang, W. J. Song, and J. S. Fang, Inverted all-inorganic CsPbI₂Br perovskite solar cells with promoted efficiency and stability by nickel incorporation, Chem. Mater. 31(21), 9032 (2019)

[71] H. R. Wang, H. Bian, Z. W. Jin, H. Zhang, L. Liang, J. L. Wen, Q. Wang, L. M. Ding, and S. Z. F. Liu, Cesium lead mixed-halide perovskites for low energy loss solar cells with efficiency beyond 17%, Chem. Mater. 31(16), 6231 (2019)

[72] Q. Zhao, A. Hazarika, L. T. Schelhas, J. Liu, E. A. Gaulding, G. R. Li, M. H. Zhang, M. F. Toney, P. C. Sercel, and J. M. Luther, Size-dependent lattice structure and confinement properties in CsPbI₃ perovskite nanocrystals: Negative surface energy for stabilization, ACS Energy Lett. 5(1), 238 (2020)

[73] H. M. Zhu, Y. P. Fu, F. Meng, X. X. Wu, Z. Z. Gong, Q. Ding, M. V. Gustafsson, M. T. Trinh, S. Jin, and X. Y. Zhu, Lead halide perovskite nanowire lasers with low lasing thresholds and high quality factors, Nat. Mater. 14(6), 636 (2015)

[74] S. Seth and A. Samanta, A facile methodology for engineering the morphology of CsPbX₃ perovskite nanocrystals under ambient condition, Sci. Rep. 6(1), 37693 (2016)

[75] X. H. Zhang, S. L. Chen, X. Wang, and A. L. Pan, Controlled synthesis and photonics applications of metal halide perovskite nanowires, Small Methods 3(1), 1800294 (2019)

[76] Q. Zhang, R. Su, W. N. Du, X. F. Liu, L. Y. Zhao, S. T. Ha, and Q. H. Xiong, Advances in small perovskite-based lasers, Small Methods 1(9), 1700163 (2017)

[77] A. Z. Pan, M. Jurow, Y. R. Zhao, F. Qiu, D. Liu, J. Yang, J. J. Urban, L. He, and Y. Liu, Templated self-assembly of one-dimensional CsPbX₃ perovskite nanocrystal superlattices, Nanoscale 9(45), 17688 (2017)

[78] D. Amgar, A. Stern, D. Rotem, D. Porath, and L. Etgar, Tunable length and optical properties of few units cell CsPbX₃ (X=Cl, Br, I) nanowires, Nano Lett. 17(2), 1007 (2017)

[79] M. Chen, Y. T. Zou, L. Z. Wu, Q. Pan, D. Yang, H. C. Hu, Y. S. Tan, Q. X. Zhong, Y. Xu, H. Y. Liu, B. Q. Sun, and Q. Zhang, Solvothermal synthesis of high-quality all-inorganic cesium lead halide perovskite nanocrystals: From nanocube to ultrathin nanowire, Adv. Funct. Mater. 27(23), 1701121 (2017)

[80] D. D. Zhang, Y. M. Yang, Y. Bekenstein, Y. Yu, N. A. Gibson, A. B. Wong, S. W. Eaton, N. Kornienko, Q. Kong, M. L. Lai, A. P. Alivisatos, S. R. Leone, and P. D. Yang, Synthesis of composition tunable and highly luminescent cesium lead halide nanowires through anion-exchange reactions, J. Am. Chem. Soc. 138(23), 7236 (2016)

[81] S. W. Eatona, M. L. Lai, N. A. Gibson, A. B. Wong, L. T. Dou, J. Ma, L. W. Wang, S. R. Leonea, and P. D. Yang, Lasing in robust cesium lead halide perovskite nanowires, Proc. Natl. Acad. Sci. USA 113(8), 1993 (2016)

[82] J. K. Sun, S. Huang, X. Z. Liu, Q. Xu, Q. H. Zhang, W. J. Jiang, D. J. Xue, J. C. Xu, J. Y. Ma, J. Ding, Q. Q. Ge, L. Gu, X. H. Fang, H. Z. Zhong, J. S. Hu, and L. J. Wan, Polar solvent induced lattice distortion of cubic CsPbI₃ nanocubes and hierarchical self-assembly into orthorhombic single-crystalline nanowires, J. Am. Chem. Soc. 140(37), 11705 (2018)

[83] Y. P. Fu, H. M. Zhu, C. C. Stoumpos, Q. Ding, J. Wang, M. G. Kanatzidis, X. Y. Zhu, and S. Jin, Broad wavelength tunable robust lasing from single-crystal nanowires of cesium lead halide perovskites (CsPbX₃, X=Cl, Br, I), ACS Nano 10(8), 7963 (2016)

[84] Y. Gao, L. Y. Zhao, Q. Y. Shang, Y. G. Zhong, Z. Liu, J. Chen, Z. P. Zhang, J. Shi, W. N. Du, Y. F. Zhang, S. L. Chen, P. Gao, X. F. Liu, X. N. Wang, and Q. Zhang, Ultrathin CsPbX₃ nanowire arrays with strong emission anisotropy, Adv. Mater. 30(31), 1801805 (2018)

[85] Y. G. Wang, M. Yasar, Z. Y. Luo, S. S. Zhou, Y. W. Yu, H. Q. Li, R. Yang, X. X. Wang, A. L. Pan, L. Gan, and T. Y. Zhai, Temperature difference triggering controlled growth of all-inorganic perovskite nanowire arrays in air, Small 14(41), 1803010 (2018)

[86] K. Park, J. W. Lee, J. D. Kim, N. S. Han, D. M. Jang, S. Jeong, J. Park, and J. K. Song, Light-matter interactions in cesium lead halide perovskite nanowire lasers, J. Phys. Chem. Lett. 7(18), 3703 (2016)

[87] H. Zhou, S. P. Yuan, X. X. Wang, T. Xu, X. Wang, H. L. Li, W. H. Zheng, P. Fan, Y. Y. Li, L. T. Sun, and A. L. Pan, Vapor growth and tunable lasing of band gap engineered cesium lead halide perovskite micro/nanorods with triangular cross section, ACS Nano 11(2), 1189 (2017)

[88] J. Pal, S. Manna, A. Mondal, S. Das, K. V. Adarsh, and A. Nag, Colloidal synthesis and photophysics of M₃Sb₂I₉ (M=Cs and Rb) nanocrystals: Lead-free perovskites, Angew. Chem. Int. Ed. 56(45), 14187 (2017)

[89] Y. Tong, B. J. Bohn, E. Bladt, K. Wang, P. Muller-Buschbaum, S. Bals, A. S. Urban, L. Polavarapu, and J. Feldmann, From precursor powders to CsPbX₃ perovskite nanowires: One-pot synthesis, growth mechanism, and oriented self-assembly, Angew. Chem. Int. Ed. 56(44), 13887 (2017)

[90] M. Shoaib, X. H. Zhang, X. X. Wang, H. Zhou, T. Xu, X. Wang, X. L. Hu, H. W. Liu, X. P. Fan, W. H. Zheng, T. F. Yang, S. Z. Yang, Q. L. Zhang, X. L. Zhu, L. T. Sun, and A. L. Pan, Directional growth of ultralong CsPbBr₃ perovskite nanowires for high-performance photodetectors, J. Am. Chem. Soc. 139(44), 15592 (2017)

[91] L. Huang, Q. G. Gao, L. D. Sun, H. Dong, S. Shi, T. Cai, Q. Liao, and C. H. Yan, Composition-graded cesium lead halide perovskite nanowires with tunable dual-color lasing performance, Adv. Mater. 30(27), 1800596 (2018)

[92] J. Liu, K. Song, Y. Shin, X. Liu, J. Chen, K. X. Yao, J. Pan, C. Yang, J. Yin, L.J. Xu, H. Yang, A. M. El-Zohry, B. Xin, S. Mitra, M. N. Hedhili, I. S. Roqan, O. F. Mohammed, Y. Han, and O. M. Bakr, Light-induced self-assembly of cubic CsPbBr₃ perovskite nanocrystals into nanowires, Chem. Mater. 31(17), 6642 (2019)

[93] P. L. Li, D. Yang, Y. S. Tan, M. H. Cao, Q. H. Zhong, M. Chen, H. C. Hu, B. Q. Sun, Y. Xu, and Q. Zhang, Consecutive interfacial transformation of cesium lead halide nanocubes to ultrathin nanowires with improved stability, ACS Appl. Mater. Interfaces 11(3), 3351 (2019)

[94] D. Yang, P. L. Li, Y. T. Zou, M. H. Cao, H. C. Hu, Q. X. Zhong, J. X. Hu, B. Q. Sun, S. Duhm, Y. Xu, and Q. Zhang, Interfacial synthesis of monodisperse CsPbBr₃ nanorods with tunable aspect ratio and clean surface for efficient light-emitting diode applications, Chem. Mater. 31(5), 1575 (2019)

[95] L. Zhang, Q. Sun, Y. Xu, L. Han, Q. Wang, Y. Yu, Z. Jin, S. Yang, and Z. Ci, Self-assembled template-confined growth of ultrathin CsPbBr₃ nanowires, Appl. Mater. Today. 18, 100449 (2019)

[96] L. Z. He, S. Pan, Z. Q. Lin, and J. Peng, Rapid route to polar solvent-directed growth of perovskite nanowires, ACS Appl. Nano Mater. 2(12), 7910 (2019)

[97] J. Chen, Z. Y. Luo, Y. P. Fu, X. X. Wang, K. J. Czech, S. H. Shen, L. J. Guo, J. C. Wright, A. L. Pan, and S. Jin, Tin(IV)-tolerant vapor-phase growth and photophysical properties of aligned cesium tin halide perovskite (CsSnX₃; X=Br, I) nanowires, ACS Energy Lett. 4(5), 1045 (2019)

[98] Y. Meng, C. Y. Lan, F. Z. Li, S. P. Yip, R. J. Wei, X. L. Kang, X. M. Bu, R. T. Dong, H. Zhang, and J. C. Ho, Direct vapor-liquid-solid synthesis of all-inorganic perovskite nanowires for high-performance electronics and optoelectronics, ACS Nano 13(5), 6060 (2019)

[99] Z. Z. Zhang, Y. X. Liu, C. Geng, S. S. Shi, X. S. Zhang, W. G. Bi, and S. Xu, Rapid synthesis of quantum-confined CsPbBr₃ perovskite nanowires using a microfluidic reactor, Nanoscale 11(40), 18790 (2019)

[100] H. Liu, M. Siron, M. Y. Gao, D. Lu, Y. Bekenstein, D. D. Zhang, L. T. Dou, A. P. Alivisatos, and P. D. Yang, Lead halide perovskite nanowires stabilized by block copolymers for Langmuir-Blodgett assembly, Nano Res. 13(5), 1453 (2020)

[101] H. Huang, L. Polavarapu, J. A. Sichert, A. S. Susha, S. Alexander, A. S. Urban, and A. L. Rogach, Colloidal lead halide perovskite nanocrystals: Synthesis, optical properties and applications, NPG Asia Mater. 8(11), e328 (2016)

[102] M. C. Weidman, M. Seitz, S. D. Stranks, and W. A. Tisdale, Highly tunable colloidal perovskite nanoplatelets through variable cation, metal, and halide composition, ACS Nano 10(8), 7830 (2016)

[103] M. C. Weidman, A. J. Goodman, and W. A. Tisdale, Colloidal halide perovskite nanoplatelets: An exciting new class of semiconductor nanomaterials, Chem. Mater. 29(12), 5019 (2017)

[104] Q. A. Akkerman, S. G. Motti, A. R. Srimath Kandada, E. Mosconi, V. D’Innocenzo, G. Bertoni, S. Marras, B. A. Kamino, L. Miranda, F. De Angelis, A. Petrozza, M. Prato, and L. Manna, Solution synthesis approach to colloidal cesium lead halide perovskite nanoplatelets with monolayer-level thickness control, J. Am. Chem. Soc. 138(3), 1010 (2016)

[105] K. H. Wang, L. Wu, L. Li, H. B. Yao, H. S. Qian, and S. H. Yu, Large-scale synthesis of highly luminescent perovskite-related CsPb₂Br₅ nanoplatelets and their fast anion exchange, Angew. Chem. Int. Ed. 128(29), 8468 (2016)

[106] Q. Zhang, R. Su, X. F. Liu, J. Xing, T. C. Sum, and Q. H. Xiong, High-quality whispering-gallery-mode lasing from cesium lead halide perovskite nanoplatelets, Adv. Funct. Mater. 26(34), 6238 (2016)

[107] L. T. Dou, Emerging two-dimensional halide perovskite nanomaterials, J. Mater. Chem. C 5(43), 11165 (2017)

[108] J. Shamsi, Z. Y. Dang, P. Bianchini, C. Canale, F. Di Stasio, R. Brescia, M. Prato, and L. Manna, Colloidal synthesis of quantum confined single crystal CsPbBr₃ nanosheets with lateral size control up to the micrometer range, J. Am. Chem. Soc. 138(23), 7240 (2016)

[109] N. N. Wang, L. Cheng, R. Ge, S. T. Zhang, Y. F. Miao, W. Zou, C. Yi, Y. Sun, Y. Cao, R. Yang, Y. Q. Wei, Q. Guo, Y. Ke, M. T. Yu, Y. Z. Jin, Y. Liu, Q. Q. Ding, D. W. Di, L. Yang, G. H. Xing, H. Tian, C. H. Jin, F. Gao, R. H. Friend, J. P. Wang, and W. Huang, Perovskite light-emitting diodes based on solution-processed self-organized multiple quantum wells, Nat. Photonics 10(11), 699 (2016)

[110] S. T. Zhang, C. Yi, N. N. Wang, Y. Sun, W. Zou, Y. Q. Wei, Y. Cao, Y. F. Miao, R. Z. Li, Y. Yin, N. Zhao, J. P. Wang, and W. Huang, Efficient red perovskite light-emitting diodes based on solution-processed multiple quantum wells, Adv. Mater. 29(22), 1606600 (2017)

[111] L. T. Dou, M. L. Lai, C. S. Kley, Y. M. Yang, C. G. Bischak, D. D. Zhang, S. W. Eaton, N. S. Ginsberg, and P. D. Yang, Spatially resolved multicolor CsPbX₃ nanowire heterojunctions via anion exchange, Proc. Natl. Acad. Sci. USA 114(28), 7216 (2017)

[112] E. Z. Shi, Y. Gao, B. P. Finkenauer, A. H. C. Akriti, and L. T. Dou, Two-dimensional halide perovskite nanomaterials and heterostructures, Chem. Soc. Rev. 47(16), 6046 (2018)

[113] A. B. Wong, Y. Bekenstein, J. Kang, C. S. Kley, D. Kim, N. A. Gibson, D. D. Zhang, Y. Yu, S. R. Leone, L. W. Wang, A. P. Alivisatos, and P. D. Yang, Strongly quantum confined colloidal cesium tin iodide perovskite nanoplates: Lessons for reducing defect density and improving stability, Nano Lett. 18(3), 2060 (2018)

[114] L. Y. Lian, G. M. Zhai, F. Cheng, Y. Xia, M. Y. Zheng, J. P. Ke, M. Y. Gao, H. Liu, D. L. Zhang, L. Y. Li, J. B. Gao, J. Tang, and J. B. Zhang, Colloidal synthesis of lead-free all-inorganic cesium bismuth bromide perovskite nanoplatelets, CrystEngComm 20(46), 7473 (2018)

[115] L. L. Wang, P. Chen, P. S. Kuttipillai, I. King, R. Staples, K. Sun, and R. R. Lunt, Epitaxial stabilization of tetragonal cesium tin iodide, ACS Appl. Mater. Interfaces 11(35), 32076 (2019)

[116] Y. P. Fu, H. M. Zhu, J. Chen, M. P. Hautzinger, X. Y. Zhu, and S. Jin, Metal halide perovskite nanostructures for optoelectronic applications and the study of physical properties, Nat. Rev. Mater. 4(3), 169 (2019)

[117] R. H. Liu, H. Zhou, Z. N. Song, X. H. Yang, D. J. Wu, Z. H. Song, H. Wang, and Y. F. Yan, Low-reflection, (110)-orientation-preferred CsPbBr₃ nanonet films for application in high-performance perovskite photodetectors, Nanoscale 11(19), 9302 (2019)

[118] J. C. Hua, X. Deng, C. Niu, F. Z. Huang, Y. Peng, W. N. Li, Z. L. Ku, and Y. B. Cheng, A pressure-assisted annealing method for high quality CsPbBr₃ film deposited by sequential thermal evaporation, RSC Advances 10(15), 8905 (2020)

[119] C. X. Huo, C. F. Fong, M. R. Amara, Y. Q. Huang, B. Chen, H. Zhang, L. J. Guo, H. J. Li, W. Huang, C. Diederichs, and Q. H. Xiong, Optical spectroscopy of single colloidal CsPbBr₃ perovskite nanoplatelets, Nano Lett. 20(5), 3673 (2020)

[120] H. Gao, W. J. Feng, H. W. Liu, S. W. Liu, Z. D. Wang, D. Yao, Y. Liu, D. K. Teng, B. Yang, and H. Zhang, Cesium-lead bromide perovskite nanoribbons with two-unit-cell thickness and large lateral dimension for deep-blue light emission, ACS Appl. Nano Mater. 3(5), 4826 (2020)

[121] A. Z. Pan, B. He, X. Y. Fan, Z. K. Liu, J. J. Urban, A. P. Alivisatos, L. He, and Y. Liu, Insight into the ligand-mediated synthesis of colloidal CsPbBr₃ perovskite nanocrystals: The role of organic acid, base, and cesium precursors, ACS Nano 10(8), 7943 (2016)

[122] X. M. Li, F. Cao, D. J. Yu, J. Chen, Z. Sun, Y. Shen, Y. Zhu, L. Wang, Y. Wei, Y. Wu, and H. Zeng, All inorganic halide perovskites nanosystem: Synthesis, structural features, optical properties and optoelectronic applications, Small 13(9), 1603996 (2017)

[123] Z. K. Wen, W. Zhai, C. Liu, J. Lin, C. Yu, Y. Huang, J. Zhang, and C. Tang, Controllable synthesis of CsPbI₃ nanorods with tunable photoluminescence emission, RSC Advances 9(43), 24928 (2019)

[124] M. V. Kovalenko, L. Protesescu, and M. I. Bodnarchuk, Properties and potential optoelectronic applications of lead halide perovskite nanocrystals, Science 358(6364), 745 (2017)

[125] X. Y. Lao, X. Y. Li, H. Agren, and G. Y. Chen, Highly controllable synthesis and DFT calculations of double/triple-Halide CsPbX₃ (X=Cl, Br, I) perovskite quantum dots: Application to light-emitting diodes, Nanomaterials (Basel) 9(2), 172 (2019)

[126] E. Oksenberg, A. Merdasa, L. Houben, I. Kaplan-Ashiri, A. Rothman, I. G. Scheblykin, E. L. Unger, and E. Joselevich, Large lattice distortions and size-dependent bandgap modulation in epitaxial halide perovskite nanowires, Nat. Commun. 11(1), 489 (2020)

[127] N. P. Dasgupta and P. D. Yang, Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion, Front. Phys. 9(3), 289 (2014)

[128] G. C. Shan, Z. Q. Yin, C. H. Shek, and W. Huang, Single photon sources with single semiconductor quantum dots, Front. Phys. 9(2), 170 (2014)

[129] J. C. Lei, X. Zhang, and Z. Zhou, Recent advances in MXene: Preparation, properties, and applications, Front. Phys. 10(3), 276 (2015)

[130] Z. Z. Yan, Z. H. Jiang, J. P. Lu, and Z. H. Ni, Interfacial charge transfer in WS₂ monolayer/CsPbBr₃ microplate heterostructure, Front. Phys. 13(4), 138115 (2018)

[131] S. Q. Luo, J. F. Wang, B. Yang, and Y. B. Yuan, Recent advances in controlling the crystallization of two-dimensional perovskites for optoelectronic device, Front. Phys. 14(5), 53401 (2019)

[132] K. S. Novoselov, D. V. Andreeva, W. Ren, and G. C. Shan, Graphene and other two-dimensional materials, Front. Phys. 14(1), 13301 (2019)

[133] B. W. Zhang, Y. X. Wang, S. L. Chou, H. K. Liu, and S. X. Dou, Fabrication of superior single-atom catalysts toward diverse electrochemical reactions, Small Methods 3(9), 1800497 (2019)

[134] B. W. Zhang, T. Sheng, Y. X. Wang, S. L. Chou, K. Davey, S. X. Dou, and S. Z. Qiao, Long-life room-temperature sodium-sulfur batteries by virtue of transition-metal-nanocluster-sulfur Interactions, Angew. Chem. Int. Ed. 58(5), 1484 (2019)

[135] Z. X. Chen, Y. J. Zhang, S. Chu, R. Sun, J. Wang, J. P. Chen, B. Wei, X. Zhang, W. H. Zhou, Y. M. Shi, and Z. Wang, Grain boundary induced ultralow threshold random laser in a single GaTe flake, ACS Appl. Mater. Interfaces 12(20), 23323 (2020)

[136] J. Wang, X. Z. Li, B. Wei, R. Sun, W. Yu, H. Y. Hoh, H. M. Xu, J. Li, X. B. Ge, Z. X. Chen, C. L. Su, and Z. C. Wang, Activating basal planes of NiPS₃ for hydrogen evolution by nonmetal heteroatom doping, Adv. Funct. Mater. 30(12), 1908708 (2020)

[137] Z. T. Li, C. J. Song, L. S. Rao, H. G. Lu, C. M. Yan, K. Cao, X. R. Ding, B. H. Yu, and Y. Tang, Synthesis of highly photoluminescent all-inorganic CsPbX₃ nanocrystals via interfacial anion exchange reactions, Nanomaterials (Basel) 9(9), 1296 (2019)

[138] C. Chen, L. W. Zhang, T. L. Shi, G. L. Liao, and Z. R. Tang, Controllable synthesis of all inorganic lead halide perovskite nanocrystals with various appearances in multiligand reaction system, Nanomaterials (Basel) 9(12), 1751 (2019)

[139] J. Y. Liu, K. Q. Chen, S. A. Khan, B. Shabbir, Y. P. Zhang, Q. Khan, and Q. L. Bao, Synthesis and optical applications of low dimensional metal-halide perovskites, Nanotechnology 31(15), 152002 (2020)

[140] B. Xin, Y. Pak, S. Mitra, D. Almalawi, N. Alwadai, Y. H. Zhang, and I. S. Roqan, Self-patterned CsPbBr₃ nanocrystals for high-performance optoelectronics, ACS Appl. Mater. Interfaces 11(5), 5223 (2019)

[141] M. Kulbak, D. Cahen, and G. Hodes, How important is the organic part of lead halide perovskite photovoltaic cells? Efficient CsPbBr₃ cells, J. Phys. Chem. Lett. 6(13), 2452 (2015)

[142] J. Liang, C. X. Wang, Y. R. Wang, Z. R. Xu, Z. Lu, Y. Ma, H. Zhu, Y. Hu, C. Xiao, X. Yi, G. Zhu, H. Lv, L. Ma, T. Chen, Z. Tie, Z. Jin, and J. Liu, All-inorganic perovskite solar cells, J. Am. Chem. Soc. 138(49), 15829 (2016)

[143] R. J. Sutton, G. E. Eperon, L. Miranda, E. S. Parrott, B. A. Kamino, J. B. Patel, M. T. Hörantner, M. B. Johnston, A. A. Haghighirad, D. T. Moore, and H. J. Snaith, Bandgap-tunable cesium lead halide perovskites with high thermal stability for efficient solar cells, Adv. Energy Mater. 6(8), 1502458 (2016)

[144] W. Li, M. U. Rothmann, A. Liu, Z. Y. Wang, Y. P. Zhang, A. R. Pascoe, J. F. Lu, L. C. Jiang, Y. Chen, F. Y. Huang, Y. Peng, Q. L. Bao, J. Etheridge, U. Bach, and Y. B. Cheng, Phase segregation enhanced ion movement in efficient inorganic CsPbIBr₂ solar cells, Adv. Energy Mater. 7(20), 1700946 (2017)

[145] S. J. Zhou, R. Tang, and L. W. Yin, Slow-photon-effect-induced photoelectrical-conversion efficiency enhancement for carbon-quantum-dot-sensitized inorganic CsPbBr₃ inverse opal perovskite solar cells, Adv. Mater. 29(43), 1703682 (2017)

[146] Y. N. Li, J. L. Duan, Y. Y. Zhao, and Q. Tang, All-inorganic bifacial CsPbBr₃ perovskite solar cells with a 98.5%-bifacial factor, Chem. Commun. 54(59), 8237 (2018)

[147] K. C. Tang, P. You, and F. Yan, Highly stable all-inorganic perovskite solar cells processed at low temperature, Solar RRL 2(8), 1800075 (2018)

[148] H. Li, G. Q. Tong, T. T. Chen, H. W. Zhu, G. P. Li, Y. J. Chang, L. Wang, and Y. Jiang, Interface engineering using a perovskite derivative phase for efficient and stable CsPbBr₃ solar cells, J. Mater. Chem. A 6(29), 14255 (2018)

[149] L. Yan, Q. F. Xue, M. Y. Liu, Z. L. Zhu, J. J. Tian, Z. C. Li, Z. Chen, Z. M. Chen, H. Yan, H. L. Yip, and Y. Cao, Interface engineering for all-inorganic CsPbI₂Br perovskite solar cells with efficiency over 14%, Adv. Mater. 30(33), 1802509 (2018)

[150] C. X. Qian, Z. Y. Deng, K. Yang, J. S. Feng, M. Z. Wang, Z. Yang, S. Z. Liu, and H. J. Feng, Interface engineering of CsPbBr₃/TiO₂ heterostructure with enhanced optoelectronic properties for all-inorganic perovskite solar cells, Appl. Phys. Lett. 112(9), 093901 (2018)

[151] Y. Z. Jiang, J. Yuan, Y. X. Ni, J. E. Yang, Y. Wang, T. G. Jiu, M. J. Yuan, and J. Chen, Reduced-dimensional α-CsPbX₃ perovskites for efficient and stable photovoltaics, Joule 2(7), 1356 (2018)

[152] J. Liang, X. Han, J. H. Yang, B. Y. Zhang, Q. Y. Fang, J. Zhang, Q. Ai, M. M. Ogle, T. Terlier, A. A. Martí, and J. Lou, Defect-engineering-enabled high-efficiency all-inorganic perovskite solar cells, Adv. Mater. 31(51), 1903448 (2019)

[153] L. Liang, Z. Z. Li, F. G. Zhou, Q. Wang, H. Zhang, Z. Xu, L. M. Ding, S. Z. Liu, and Z. W. Jin, The humidity-insensitive fabrication of efficient CsPbI₃ solar cells in ambient air, J. Mater. Chem. A 7(47), 26776 (2019)

[154] J. Li, R. R. Gao, F. Gao, J. Lei, H. X. Wang, X. Wu, J. B. Li, H. Liu, X. D. Hua, and S. Z. Liu, Fabrication of efficient CsPbBr₃ perovskite solar cells by single-source thermal evaporation, J. Alloys Compd. 818, 152903 (2020)

[155] H. Bian, H. R. Wang, Z. Z. Li, F. G. Zhou, Y. K. Xu, H. Zhang, Q. Wang, L. M. Ding, S. Z. Liu, and Z. W. Jin, Unveiling the effects of hydrolysis-derived DMAI/DMAPbI intermediate compound on the performance of CsPbI₃ solar cells, Adv. Sci. 7(9), 1902868 (2020)

[156] Q. S. Zeng, X. Y. Zhang, C. M. Liu, T. L. Feng, Z. L. Chen, W. T. Zheng, H. Zhang, and B. Yang, Inorganic CsPbI₂Br perovskite solar cells: The progress and perspective, Sol. RRL 3(1), 1800239 (2019)

[157] P. P. Li, Y. M. Duan, Y. Lu, N. Xiao, Z. Y. Zeng, S. Q. Xu, and J. J. Zhang, Nanocrystalline structure control and tunable luminescence mechanism of Eu-doped CsPbBr₃ quantum dot glass for WLEDs, Nanoscale 12(12), 6630 (2020)

[158] L. L. Wang, B. B. Fan, B. Zheng, Z. B. Yang, P. G. Yin, and L. J. Huo, Organic functional materials: Recent advances in all-inorganic perovskite solar cells, Sustain. Energ. Fuels 4(5), 2134 (2020)

[159] K. Jiang, J. Wang, F. Wu, Q. F. Xue, Q. Yao, J. Q. Zhang, Y. H. Chen, G. Y. Zhang, Z. L. Zhu, H. Yan, L. N. Zhu, and H. L. Yip, Dopant-free organic hole-transporting material for efficient and stable inverted all-inorganic and hybrid perovskite solar cells, Adv. Mater. 32(16), 1908011 (2020)

[160] S. Mahato, A. Ghorai, S. K. Srivastava, M. Modak, S. Singh, and S. K. Ray, Highly air-stable single-crystalline b-CsPbI₃ nanorods: a platform for inverted perovskite solar cells, Adv. Energy Mater. 10(30), 2001305 (2020)

[161] J. Z. Song, J. H. Li, X. M. Li, L. M. Xu, Y. H. Dong, and H. B. Zeng, Quantum dot light-emitting diodes based on inorganic perovskite cesium lead halides (CsPbX₃), Adv. Mater. 27(44), 7162 (2015)

[162] G. R. Yettapu, D. Talukdar, S. Sarkar, A. Swarnkar, A. Nag, P. Ghosh, and P. Mandal, THz conductivity within colloidal CsPbBr₃ perovskite nanocrystals: Remarkably high carrier mobilities and large diffusion lengths, Nano Lett. 16(8), 4838 (2016)

[163] S. Wei, Y. C. Yang, X. J. Kang, L. Wang, L. J. Huang, and D. C. Pan, Homogeneous synthesis and electroluminescenc device of highly luminescent CsPbBr₃ perovskite nanocrystals, Inorg. Chem. 56(5), 2596 (2017)

[164] Z. Wu, J. Wei, Y. Sun, J. Wu, Y. Hou, P. Wang, N. Wang, and Z. Zhao, Air-stable all-inorganic perovskite quantum dot inks for multicolor patterns and white LEDs, J. Mater. Sci. 54(9), 6917 (2019)

[165] Z. Wang, Z. Luo, C. Zhao, Q. Guo, Y. Wang, F. Wang, X. Bian, A. Alsaedi, T. Hayat, and Z. Tan, Efficient and stable pure green all-inorganic perovskite CsPbBr₃ light-emitting diodes with a solution-processed NiO_x interlayer, J. Phys. Chem. C 121(50), 28132 (2017)

[166] H. Wu, Y. Zhang, M. Lu, X. Zhang, C. Sun, T. Zhang, V. L. Colvin, and W. W. Yu, Surface ligand modification of cesium lead bromide nanocrystals for improved light-emitting performance, Nanoscale 10(9), 4173 (2018)

[167] J. H. Park, A. Y. Lee, J. C. Yu, Y. S. Nam, Y. Choi, J. Park, and M. H. Song, Surface ligand engineering for efficient perovskite nanocrystal-based light-emitting diodes, ACS Appl. Mater. Interfaces 11(8), 8428 (2019)

[168] P. Song, B. Qiao, D. Song, Z. Liang, D. Gao, J. Cao, Z. Shen, Z. Xu, and S. Zhao, Colour- and structure-stable CsPbBr₃-CsPb₂Br₅ compounded quantum dots with tunable blue and green light emission, J. Alloys Compd. 767, 98 (2018)

[169] K. H. Wang, B. S. Zhu, J. S. Yao, and H. B. Yao, Chemical regulation of metal halide perovskite nanomaterials for efficient light-emitting diodes, Sci. China Chem. 61(9), 1047 (2018)

[170] J. J. Si, Y. Liu, Z. F. He, H. Du, K. Du, D. Chen, J. Li, M. M. Xu, H. Tian, H. P. He, D. W. Di, C. Q. Lin, Y. C. Cheng, J. P. Wang, and Y. Z. Jin, Efficient and high-color-purity light-emitting diodes based on in-situ grown films of CsPbX₃ (X=Br, I) nanoplates with controlled thicknesses, ACS Nano 11(11), 11100 (2017)

[171] H. Sasaki, N. Kamata, Z. Honda, and T. Yasuda, Improved thermal stability of CsPbBr₃ quantum dots by ligand exchange and their application to light-emitting diodes, Appl. Phys. Express 12(3), 035004 (2019)

[172] J. Q. Li, X. Shan, S. G. R. Bade, T. Geske, Q. L. Jiang, X. Yang, and Z. B. Yu, Single-layer halide perovskite light-emitting diodes with sub-band gap turn-on voltage and high brightness, J. Phys. Chem. Lett. 7(20), 4059 (2016)

[173] S. Wu, S. Zhao, Z. Xu, D. Song, B. Qiao, H. Yue, J. Yang, X. Zheng, and P. Wei, Highly bright and stable all-inorganic perovskite light-emitting diodes with methoxypolyethylene glycols modified CsPbBr₃ emission layer, Appl. Phys. Lett. 113(21), 213501 (2018)

[174] T. Chiba, Y. Hayashi, H. Ebe, K. Hoshi, J. Sato, S. Sato, Y. J. Pu, S. Ohisa, and J. Kido, Anion-exchange red perovskite quantum dots with ammonium iodine salts for highly efficient light-emitting devices, Nat. Photonics 12(11), 681 (2018)

[175] L. Song, X. Guo, Y. Hu, Y. Lv, J. Lin, Y. Fan, N. Zhang, and X. Liu, Improved performance of CsPbBr₃ perovskite light-emitting devices by both boundary and interface defects passivation, Nanoscale 10(38), 18315 (2018)

[176] J. Pan, L. N. Quan, Y. B. Zhao, W. Peng, B. Murali, S. P. Sarmah, M. J. Yuan, L. Sinatra, N. M. Alyami, J. K. Liu, E. Yassitepe, Z. Y. Yang, O. Voznyy, R. Comin, M. N. Hedhili, O. F. Mohammed, Z. H. Lu, D. H. Kim, E. H. Sargent, M. Osman, and O. M. Bakr, Highly efficient perovskite-quantum-dot light-emitting diodes by surface engineering, Adv. Mater. 28(39), 8718 (2016)

[177] Q. S. Shan, J. Z. Song, Y. S. Zou, J. H. Li, L. M. Xu, J. Xue, Y. H. Dong, B. N. Han, J. W. Chen, and H. B. Zeng, High performance metal halide perovskite light-emitting diode: From material design to device optimization, Small 13(45), 1701770 (2017)

[178] L. M. Xu, J. H. Li, B. Cai, J. Z. Song, F. J. Zhang, T. Fang, and H. B. Zeng, A bilateral interfacial passivation strategy promoting efficiency and stability of perovskite quantum dot light-emitting diodes, Nat. Commun. 11, 3902 (2020)

[179] G. Lozano, The role of metal halide perovskites in next-generation lighting devices, J. Phys. Chem. Lett. 9(14), 3987 (2018)

[180] D. X. Luo, Q. Chen, Y. Qiu, M. L. Zhang, and B. Q. Liu, Device engineering for all-inorganic perovskite light-emitting diodes, Nanomaterials (Basel) 9(7), 1007 (2019)

[181] Y. P. Fu, H. M. Zhu, C. C. Stoumpos, Q. Ding, J. Wang, M. G. Kanatzidis, X. Y. Zhu, and S. Jin, Broad wavelength tunable robust lasing from single-crystal nanowires of cesium lead halide perovskites (CsPbX₃, X=Cl, Br, I), ACS Nano 10(8), 7963 (2016)

[182] K. Park, J. W. Lee, J. D. Kim, N. S. Han, D. M. Jang, S. Jeong, J. Park, and J. K. Song, Light-matter interactions in cesium lead halide perovskite nanowire lasers, J. Phys. Chem. Lett. 7(18), 3703 (2016)

[183] S. Zhang, Q. Y. Shang, W. N. Du, J. Shi, Z. Y. Wu, Y. Mi, J. Chen, F. J. Liu, Y. Z. Li, M. Liu, Q. Zhang, and X. F. Liu, Strong exciton-photon coupling in hybrid inorganic-organic perovskite micro/nanowires, Adv. Opt. Mater. 6(2), 1701032 (2018)

[184] X. X. Wang, M. Shoaib, X. Wang, X. H. Zhang, M. He, Z. Y. Luo, W. H. Zheng, H. L. Li, T. Yang, X. Zhu, L. Ma, and A. Pan, High-quality in-plane aligned CsPbX₃ perovskite nanowire lasers with composition-dependent strong exciton-photon coupling, ACS Nano 12(6), 6170 (2018)

[185] T. J. S. Evans, A. Schlaus, Y. P. Fu, X. J. Zhong, T. L. Atallah, M. S. Spencer, L. E. Brus, S. Jin, and X. Y. Zhu, Continuous-wave lasing in cesium lead bromide perovskite nanowires, Adv. Opt. Mater. 6(2), 1700982 (2018)

[186] X. X. Wang, H. Zhou, S. P. Yuan, W. H. Zheng, Y. Jiang, X. J. Zhuang, H. J. Liu, Q. L. Zhang, X. L. Zhu, X. Wang, and A. L. Pan, Cesium lead halide perovskite triangular nanorods as high-gain medium and effective cavities for multiphoton-pumped lasing, Nano Res. 10(10), 3385 (2017)

[187] L. Jiang, R. M. Liu, R. L. Su, Y. Yu, H. F. Xu, Y. M. Wei, Z. K. Zhou, and X. Wang, Continuous wave pumped single-mode nanolasers in inorganic perovskites with robust stability and high quantum yield, Nanoscale 10(28), 13565 (2018)

[188] L. Yang, Z. Q. Li, C. Liu, X. R. Yao, H. Q. Li, J. S. Liu, P. W. Zhu, B. B. Liu, T. Cui, C. Sun, and Y. J. Bao, Temperature-dependent lasing of CsPbI₃ triangular pyramid, J. Phys. Chem. Lett. 10(22), 7056 (2019)

[189] X. S. Tang, Y. Bian, Z. Z. Liu, J. Du, M. Li, Z. P. Hu, J. Yang, W. W. Chen, and L. D. Sun, Room-temperature up-conversion random lasing from CsPbBr₃ quantum dots with TiO₂ nanotubes, Opt. Lett. 44(19), 4706 (2019)

[190] Z. Liu, Q. Y. Shang, C. Li, L. Y. Zhao, Y. Gao, Q. Li, J. Chen, S. Zhang, X. F. Liu, Y. S. Fu, and Q. Zhang, Temperature-dependent photoluminescence and lasing properties of CsPbBr₃ nanowires, Appl. Phys. Lett. 114(10), 101902 (2019)

[191] Z. Z. Liu, J. Yang, J. Du, Z. P. Hu, T. C. Shi, Z. Y. Zhang, Y. Q. Liu, X. S. Tang, Y. X. Leng, and R. X. Li, Robust subwavelength single-mode perovskite nanocuboid laser, ACS Nano 12(6), 5923 (2018)

[192] Y. Wang, X. M. Li, V. Nalla, H. B. Zeng, and H. D. Sun, Solution-processed low threshold vertical cavity surface emitting lasers from all-inorganic perovskite nanocrystals, Adv. Funct. Mater. 27(13), 1605088 (2017)

[193] A. P. Pushkarev, V. I. Korolev, D. I. Markina, F. E. Komissarenko, A. Naujokaitis, A. Drabavičius, V. Pakštas, M. Franckevičius, S. A. Khubezhov, D. A. Sannikov, A. V. Zasedatelev, P. G. Lagoudakis, A. A. Zakhidov, and S. V. Makarov, Few-minute synthesis of CsPbBr₃ nanolasers with a high quality factor by spraying at ambient conditions, ACS Appl. Mater. Interfaces 11(1), 1040 (2019)

[194] G. J. Xu, Y. Li, J. Y. Yan, X. D. Lv, Y. Liu, and B. Cai, In-plane self-assembly and lasing performance of cesium lead halide perovskite nanowires, Mater. Res. Lett. 7(5), 203 (2019)

[195] Z. Z. Liu, Z. P. Hu, T. C. Shi, J. Du, J. Yang, Z. Y. Zhang, X. S. Tang, and Y. X. Leng, Stable and enhanced frequency up-converted lasing from CsPbBr₃ quantum dots embedded in silica sphere, Opt. Express 27(7), 9459 (2019)

[196] F. Yan, S. T. Tan, X. Li, and H. V. Demir, Light generation in lead halide perovskite nanocrystals: LEDs, color converters, lasers, and other applications, Small 15(47), 1902079 (2019)

[197] C. X. Bao, J. Yang, S. Bai, W. D. Xu, Z. B. Yan, Q. Y. Xu, J. M. Liu, W. J. Zhang, and F. Gao, High performance and stable all-inorganic metal halide perovskite-based photodetectors for optical communication applications, Adv. Mater. 30(38), 1803422 (2018)

[198] M. M. Stylianakis, T. Maksudov, A. Panagiotopoulos, G. Kakavelakis, and K. Petridis, Inorganic and hybrid perovskite based laser devices: A review, Materials (Basel) 12(6), 859 (2019)

[199] Z. Z. Liu, S. H. Huang, J. Du, C. W. Wang, and Y. X. Leng, Advances in inorganic and hybrid perovskites for miniaturized lasers, Nanophotonics 9(8), 2251 (2020)

[200] A. S. Polushkin, E. Y. Tiguntseva, A. P. Pushkarev, and S. Makarov, Single-particle perovskite lasers: From material properties to cavity design, Nanophotonics 9(3),

[201] Y. H. Dong, Y. Gu, Y. S. Zou, J. Z. Song, L. M. Xu, J. H. Li, J. Xue, X. M. Li, and H. B. Zeng, Improving all-inorganic perovskite photodetectors by preferred orientation and plasmonic effect, Small 12(40), 5622 (2016)

[202] X. H. Liu, D. J. Yu, F. Cao, X. M. Li, J. P. Ji, J. Chen, X. F. Song, and H. B. Zeng, Low-voltage photodetectors with high responsivity based on solution-processed micrometer-scale all-inorganic perovskite nanoplatelets, Small 13(25), 1700364 (2017)

[203] X. M. Li, D. J. Yu, J. Chen, Y. Wang, F. Cao, Y. Wei, Y. Wu, L. Wang, Y. Zhu, Z. Sun, J. Ji, Y. Shen, H. Sun, and H. Zeng, Constructing fast carrier tracks into flexible perovskite photodetectors to greatly improve responsivity, ACS Nano 11(2), 2015 (2017)

[204] T. Yang, Y. P. Zheng, Z. T. Du, W. N. Liu, Z. B. Yang, F. M. Gao, L. Wang, K. C. Chou, X. M. Hou, and W. Y. Yang, Superior photodetectors based on all-inorganic perovskite CsPbI₃ nanorods with ultrafast response and high stability, ACS Nano 12(2), 1611 (2018)

[205] Z. T. Du, D. F. Fu, T. Yang, Z. Fang, W. N. Liu, F. M. Gao, L. Wang, Z. B. Yang, J. Teng, H. Zhang, and W. Y. Yang, Photodetectors with ultra-high detectivity based on stabilized all-inorganic perovskite CsPb_0.922Sn_0.078I₃ nanobelts, J. Mater. Chem. C Mater. Opt. Electron. Devices 6(23), 6287 (2018)

[206] W. Zhai, J. Lin, C. Li, S. M. Hu, Y. Huang, C. Yu, Z. K. Wen, Z. Y. Liu, Y. Fang, and C. Tang, Solvothermal synthesis of cesium lead halide perovskite nanowires with ultra-high aspect ratios for high-performance photodetectors, Nanoscale 10(45), 21451 (2018)

[207] P. B. Gui, Z. Chen, B. R. Li, F. Yao, X. L. Zheng, Q. Q. Lin, and G. J. Fang, High-performance photodetectors based on single all-inorganic CsPbBr₃ perovskite microwire, ACS Photonics 5(6), 2113 (2018)

[208] M. M. Han, J. M. Sun, M. Peng, N. Han, Z. H. Chen, D. Liu, Y. N. Guo, S. Zhao, C. X. Shan, T. Xu, X. T. Hao, W. D. Hu, and Z. X. Yang, Controllable growth of lead-free all-inorganic perovskite nanowire array with fast and stable near-infrared photodetection, J. Phys. Chem. C 123(28), 17566 (2019)

[209] T. B. Yang, F. Li, and R. K. Zheng, Recent progress on cesium lead halide perovskites for photodetection applications, ACS Appl. Electron. Mater. 1(8), 1348 (2019)

[210] Z. X. Zhang, C. Li, Y. Lu, X. W. Tong, F. X. Liang, X. Y. Zhao, D. Wu, C. Xie, and L. B. Luo, Sensitive deep ultraviolet photodetector and image sensor composed of inorganic lead-free Cs₃Cu₂I₅ perovskite with wide bandgap, J. Phys. Chem. Lett. 10(18), 5343 (2019)

[211] C. C. Tian, F. Wang, Y. P. Wang, Z. Yang, X. J. Chen, J. J. Mei, H. Z. Liu, and D. X. Zhao, Chemical vapor deposition method grown all-inorganic perovskite microcrystals for self-powered photodetectors, ACS Appl. Mater. Interfaces 11(17), 15804 (2019)

[212] M. N. Xue, H. Zhou, G. K. Ma, L. Yang, Z. H. Song, J. Zhang, and H. Wang, Investigation of the stability for self-powered CsPbBr₃ perovskite photodetector with an all-inorganic structure, Sol. Energy Mater. Sol. Cells 187, 69 (2018)

[213] Z. T. Du, D. F. Fu, J. Teng, L. Wang, F. M. Gao, W. Y. Yang, H. Zhang, and X. S. Fang, CsPbI₃ nanotube photodetectors with high detectivity, Small 15(52), 1905253 (2019)

[214] Y. Yang, H. T. Dai, F. Yang, Y. T. Zhang, D. Luo, X. L. Zhang, K. Wang, X. W. Sun, and J. Q. Yao, All-perovskite photodetector with fast response, Nanoscale Res. Lett. 14(1), 291 (2019)

[215] G. B. Cen, Y. J. Liu, C. X. Zhao, G. Wang, Y. Fu, G. H. Yan, Y. Yuan, C. H. Su, Z. J. Zhao, and W. J. Mai, Atomic-layer deposition-assisted double-side interfacial engineering for high-performance flexible and stable CsPbBr₃ perovskite photodetectors toward visible light communication applications, Small 15(36), 1902135 (2019)

[216] Z. Ji, Y. J. Liu, W. J. Li, C. X. Zhao, and W. J. Mai, Reducing current fluctuation of Cs₃Bi₂Br₉ perovskite photodetectors for diffuse reflection imaging with wide dynamic range, Sci. Bull. (Beijing) 65(16), 1371 (2020)

[217] G. Q. Tong, M. W. Jiang, D. Y. Son, L. B. Qiu, Z. H. Liu, L. K. Ono, and Y. B. Qi, Inverse growth of large-grain-size and stable inorganic perovskite micronanowire photodetectors, ACS Appl. Mater. Interfaces 12(12), 14185 (2020)

[218] M. I. Saleem, S. Y. Yang, R. N. Zhi, M. Sulaman, P. V. Chandrasekar, Y. R. Jiang, Y. Tang, A. Batool, and B. S. Zou, Surface engineering of all-inorganic perovskite quantum dots with quasi core-shell technique for high-performance photodetectors, Adv. Mater. Interfaces 7(11), 2000360 (2020)

[219] P. B. Gui, J. H. Li, X. L. Zheng, H. B. Wang, F. Yao, X. Z. Hu, Y. J. Liu, and G. J. Fang, Self-driven all-inorganic perovskite microplatelet vertical Schottky junction photodetectors with a tunable spectral response, J. Mater. Chem. C 8(20), 6804 (2020)

[220] J. Z. Li, J. M. Xia, Y. Liu, S. W. Zhang, C. J. Teng, X. Zhang, B. L. Liu, S. C. Zhao, S. X. Zhao, B. H. Li, G. C. Xing, F. Y. Kang, and G. D. Wei, Ultrasensitive organic-modulated CsPbBr₃ quantum dot photodetectors via fast interfacial charge transfer, Adv. Mater. Interfaces 7(2), 1901741 (2020)

[221] Y. Hou, L. M. Wang, X. M. Zou, D. Wan, C. Liu, G. L. Li, X. Q. Liu, Y. F. Liu, C. Z. Jiang, J. C. Ho, and L. Liao, Substantially improving device performance of all-inorganic perovskite-based phototransistors via indium tin oxide nanowire incorporation, Small 16(5), 1905609 (2020)

[222] Y. Gao, L. Y. Zhao, Q. Y. Shang, Y. G. Zhong, Z. Liu, J. Chen, Z. P. Zhang, J. Shi, W. N. Du, Y. F. Zhang, S. L. Chen, P. Gao, X. F. Liu, X. N. Wang, and Q. Zhang, Ultrathin CsPbX₃ nanowire arrays with strong emission anisotropy, Adv. Mater. 30(31), 1801805 (2018)

[223] S. Zhou, G. D. Zhou, Y. H. Li, X. Xu, Y. J. Hsu, J. B. Xu, N. Zhao, and X. H. Lu, Understanding charge transport in all-inorganic halide perovskite nanocrystal thin-film field effect transistors, ACS Energy Lett. 5(8), 2614 (2020)

[224] D. K. Kim, D. Choi, M. Park, K. S. Jeong, and J. H. Choi, Cesium lead bromide quantum dot light-emitting field-effect transistors, ACS Appl. Mater. Inter. 12(19), 21944 (2020)

[225] G. Rainò, G. Nedelcu, L. Protesescu, M. I. Bodnarchuk, M. V. Kovalenko, R. F. Mahrt, and T. Stöferle, Single cesium lead halide perovskite nanocrystals at low temperature: fast single-photon emission, reduced blinking, and exciton fine structure, ACS Nano 10(2), 2485 (2016)

[226] Q. A. Akkerman, G. Rainò, M. V. Kovalenko, and L. Manna, Genesis, challenges and opportunities for colloidal lead halide perovskite nanocrystals, Nat. Mater. 17(5), 394 (2018)

[227] E. Hassanabadi, M. Latifi, A. F. Gualdrón-Reyes, S. Masi, S. J. Yoon, M. Poyatos, B. Julián-López, and I. Mora-Seró, Ligand & band gap engineering: Tailoring the protocol synthesis for achieving high-quality CsPbI₃ quantum dots, Nanoscale 12(26), 14194 (2020)

[228] R. Zhang, Y. X. Yuan, J. H. Li, Z. X. Qin, Q. M. Zhang, B. Y. Xiong, Z. S. Wang, F. H. Chen, X. J. Du, and W. Yang, Ni and K ion doped CsPbX₃ NCs for the improvement of luminescence properties by a facile synthesis method in ambient air, J. Lumin. 221, 117044 (2020)

[229] K. Thesika and A. V. Murugan, Microwave-enhanced chemistry at solid-liquid interfaces: Synthesis of all-inorganic CsPbX₃ nanocrystals and unveiling the anion-induced evolution of structural and optical properties, Inorg. Chem. 59(9), 6161 (2020)

[230] R. Y. Wang, Y. Muhammad, X. Xu, M. Ran, Q. F. Zhang, J. C. Zhong, F. W. Zhuge, H. Q. Li, L. Gan, and T. Y. Zhai, Facilitating all-inorganic halide perovskites fabrication in confined-space deposition, Small Methods 4(7), 2000102 (2020)

[231] Y. Bekenstein, J. C. Dahl, J. M. Huang, W. T. Osowiecki, J. K. Swabeck, E. M. Chan, P. D. Yang, and A. P. Alivisatos, The making and breaking of lead-free double perovskite nanocrystals of cesium silver-bismuth halide compositions, Nano Lett. 18(6), 3502 (2018)

[232] J. M. Huang, T. Lei, M. Siron, Y. Zhang, S. Yu, F. Seeler, A. Dehestani, L. N. Quan, K. Schierle-Arndt, and P. D. Yang, Lead-free cesium europium halide perovskite nanocrystals, Nano Lett. 20(5), 3734 (2020)

Rights & permissions

Higher Education Press 2021