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Halide perovskites are very promising for display applications because of their excellent luminescence yield, tunable color in the visible spectrum, high color purity, and low material cost. In recent years, perovskite-based light-emitting diodes (PeLEDs) have obtained significant progress in terms of luminance, external quantum efficiency, and stability. Now the device metrics of best-performing blue, green, and red PeLEDs are summarized and compared, in a hope to bring rese [Detail] ...
Metal halide perovskites are a class of materials that are ideal for photodetectors and solar cells due to their excellent optoelectronic properties. Their low-cost and low temperature synthesis have made them attractive for extensive research aimed at revolutionizing the semiconductor industry. The rich chemistry of metal halide perovskites allows compositional engineering resulting in facile tuning of the desired optoelectronic properties. Moreover, using different experimental synthesis and deposition techniques such as solution processing, chemical vapor deposition and hot-injection methods, the dimensionality of the perovskites can be altered from 3D to 0D, each structure opening a new realm of applications due to their unique properties. Dimensionality engineering includes both morphological engineering–reducing the thickness of 3D perovskite into atomically thin films–and molecular engineering–incorporating long-chain organic cations into the perovskite mixture and changing the composition at the molecular level. The optoelectronic properties of the perovskite structure including its band gap, binding energy and carrier mobility depend on both its composition and dimensionality. The plethora of different photodetectors and solar cells that have been made with different compositions and dimensions of perovskite will be reviewed here. We will conclude our review by discussing the kinetics and dynamics of different dimensionalities, their inherent stability and toxicity issues, and how reaching similar performance to 3D in lower dimensionalities and their large-scale deployment can be achieved.
With strong electron–phonon coupling, the self-trapped excitons are usually formed in materials, which leads to the local lattice distortion and localized excitons. The self-trapping strongly depends on the dimensionality of the materials. In the three-dimensional case, there is a potential barrier for self-trapping, whereas no such barrier is present for quasi-one-dimensional systems. Two-dimensional (2D) systems are marginal cases with a much lower potential barrier or nonexistent potential barrier for the self-trapping, leading to the easier formation of self-trapped states. Self-trapped excitons emission exhibits a broadband emission with a large Stokes shift below the bandgap. 2D perovskites are a class of layered structure material with unique optical properties and would find potential promising optoelectronic. In particular, self-trapped excitons are present in 2D perovskites and can significantly influence the optical and electrical properties of 2D perovskites due to the soft characteristic and strong electron–phonon interaction. Here, we summarized the luminescence characteristics, origins, and characterizations of self-trapped excitons in 2D perovskites and finally gave an introduction to their applications in optoelectronics.
Perovskite-based optoelectronic devices, especially perovskite light-emitting diodes (PeLEDs) and perovskite solar cells, have recently attracted considerable attention. The National Renewable Energy Laboratory (NREL) chart inspires us to develop a counterpart for PeLEDs. In this study, we collect the record performance of PeLEDs including several new entries to address their latest external quantum efficiency (EQE), highest luminance, and stability status. We hope that these performance tables and future updated versions will show the frontiers of PeLEDs, assist researchers in capturing the overview of this field, identify the remaining challenges, and predict the promising research directions.
Si-based solar cells, which have the advantages of high efficiency, low manufacturing costs, and outstanding stability, are dominant in the photovoltaic market. Currently, state-of-the-art Si-based solar cells are approaching the practical limit of efficiency. Constructing Si-based tandem solar cells is one available pathway to break the theoretical efficiency limit of single-junction silicon solar cells. Various top cells have been explored recently in the construction of Si-based tandem devices. Nevertheless, many challenges still stand in the way of extensive commercial application of Si-based tandem solar cells. Herein, we summarize the recent progress of representative Si-based tandem solar cells with different top cells, such as III-V solar cells, wide-bandgap perovskite solar cells, cadmium telluride (CdTe)-related solar cells, Cu(In,Ga)(Se,S)2 (CIGS)-related solar cells, and amorphous silicon (a-Si) solar cells, and we analyze the main bottlenecks for their next steps of development. Subsequently, we suggest several potential candidate top cells for Si-based tandem devices, such as Sb2S3, Se, CdSe, and Cu2O. These materials have great potential for the development of high-performance and low-cost Si-based tandem solar cells in the future.
Over the last decade, the power conversion efficiency of hybrid organic–inorganic perovskite solar cells (PSCs) has increased dramatically from 3.8% to 25.2%. This rapid progress has been possible due to the accurate control of the morphology and crystallinity of solution-processed perovskites, which are significantly affected by the concentration of the precursor used. This study explores the influence of precursor concentrations on the performance of printable hole-conductor-free mesoscopic PSCs via a simple one-step drop-coating method. The results reveal that lower concentrations lead to larger grains with inferior pore filling, while higher concentrations result in smaller grains with improved pore filling. Among concentrations ranging from 0.24–1.20 M, devices based on a moderate strength of 0.70 M were confirmed to exhibit the best efficiency at 16.32%.
Cesium-based inorganic perovskite solar cells (PSCs) are paid more attention because of their potential thermal stability. However, prevalent salt-doped 2,2′,7,7′-tetrakis(N,N-dipmethoxyphenylamine)9,9′-spirobifluorene (Spiro-OMeTAD) as hole-transport materials (HTMs) for a high-efficiency inorganic device has an unfortunate defective thermal stability. In this study, we apply poly(3-hexylthiophene-2,5-diyl) (P3HT) as the HTM and design all-inorganic PSCs with an indium tin oxide (ITO)/SnO2/LiF/CsPbI3−xBrx/P3HT/Au structure. As a result, the CsPbI3−xBrx PSCs achieve an excellent performance of 15.84%. The P3HT HTM-based device exhibits good photo-stability, maintaining ~80% of their initial power conversion efficiency over 280 h under one Sun irradiation. In addition, they also show better thermal stability compared with the traditional HTM Spiro-OMeTAD.
Organic–inorganic hybrid perovskite solar cells have generated wide interest due to the rapid development of their photovoltaic conversion efficiencies. However, the majority of the reported devices have been fabricated via spin coating with a device area of <1 cm2. In this study, we fabricated a wide-bandgap formamidinium lead bromide (FAPbBr3) film using a cost-effective, high-yielding doctor-blade-coating process. The effects of different surfactants, such as l-α-phosphatidylcholine, polyoxyethylene sorbitan monooleate, sodium lauryl sulfonate, and hexadecyl trimethyl ammonium bromide, were studied during the printing process. Accompanying the optimization of the blading temperature, crystal sizes of over 10 mm and large-area perovskite films of 5 cm × 5 cm were obtained using this method. The printed FAPbBr3 solar cells exhibited a short-circuit current density of 8.22 mA/cm2, an open-circuit voltage of 1.175 V, and an efficiency of 7.29%. Subsequently, we replaced the gold with silver nanowires as the top electrode to prepare a semitransparent perovskite solar cell with an average transmittance (400–800 nm) of 25.42%, achieving a high-power efficiency of 5.11%. This study demonstrates efficient doctor-blading printing for preparing large-area FAPbBr3 films that possess high potential for applications in building integrated photovoltaics.
Metal halide perovskites have received considerable attention in the field of electroluminescence, and the external quantum efficiency of perovskite light-emitting diodes has exceeded 20%. CH3NH3PbBr3 has been intensely investigated as an emitting layer in perovskite light-emitting diodes. However, perovskite films comprising CH3NH3PbBr3 often exhibit low surface coverage and poor crystallinity, leading to high current leakage, severe nonradiative recombination, and limited device performance. Herein, we demonstrate a rationale for composition engineering to obtain high-quality perovskite films. We first reduce pinholes by adding excess CH3NH3Br to the actual CH3NH3PbBr3 films, and we then add CsBr to improve the crystalline quality and to passivate nonradiative defects. As a result, the (CH3NH3)1−xCsxPbBr3 based perovskite light-emitting diodes exhibit significantly improved external quantum and power efficiencies of 6.97% and 25.18 lm/W, respectively, representing an improvement in performance dozens of times greater than that of pristine CH3NH3PbBr3-based perovskite light-emitting diodes. Our study demonstrates that composition engineering is an effective strategy for enhancing the device performance of perovskite light-emitting diodes.
Although laser pumping using electron beam (EB) has high transient power output and easy modulation based on perovskite quantum dot (PQD) film, its lasing emitting direction is the same as the pumped EB’s direction. Thus, realizing the conventional direct device structure through the film lasing mechanism is extremely difficult. Therefore, using the random lasing principle, herein, we proposed a corona modulation device structure based on PQDs random laser pumped using an EB. We discussed and stimulated the optimized designed method of the device in terms of parameters of the electronic optical device and the utilization ratio of output power and its modulation extinction ratio, respectively. According to the simulation results, this type of device structure can effectively satisfy the new random lasing mechanism in terms of high-speed and high-power modulation.
