For most applications based on the photoelectric effect, uncontrollable photogenerated carrier behavior, such as trapping and recombination, is a common issue that reduces the carrier utilization efficiency. Herein, a sub-nano cluster (Pd, Ru, and PdRu alloy) decoration strategy is proposed to manipulate the photogenerated carrier behavior in MoS2 to optimize the optoelectronic properties. After decoration, electrons can flow into sub-nano cluster through Pd—S bonds and then return to MoS2 through Ru—S bonds at the sub-nano cluster/MoS2 interface when holes are left in the channel for collection to achieve efficient carrier separation. In addition, the formation of metal—S bonds also leads to the generation of mid-gap states, which enables light absorption over a wide wavelength range. Therefore, the photodetector based on PdRu/MoS2 shows broadband photodetection ability from 532 to 1550 nm with high responsivity/external quantum efficiency of 310.8 A W–1/7 × 104% (532 nm), 4.2 A W–1/527% (980 nm), and 7.14 mA W–1/0.5% (1550 nm), as well as a fast response speed (rise/decay time of 11.5/12.0 ms). Our work offers new insight into manipulating the photogenerated carrier behavior to optimize the performance of semiconducting 2D materials for practical optoelectronic applications.
Metal oxide-supported multielement alloy nanoparticles are very promising as highly efficient and cost-effective catalysts with a virtually unlimited compositional space. However, controllable synthesis of ultrasmall multielement alloy nanoparticles (us-MEA-NPs) supported on porous metal oxides with a homogeneous elemental distribution and good catalytic stability during long-term operation is extremely challenging due to their oxidation and strong immiscibility. As a proof of concept that such synthesis can be realized, this work presents a general “bottom-up” l ultrasonic-assisted, simultaneous electro-oxidation–reduction-precipitation strategy for alloying dissimilar elements into single NPs on a porous support. One characteristic of this technique is uniform mixing, which results from simultaneous rapid thermal decomposition and reduction and leads to multielement liquid droplet solidification without aggregation. This process was achieved through a synergistic combination of enhanced electrochemical and plasma-chemical phenomena at the metal–electrolyte interface (electron energy of 0.3–1.38 eV at a peak temperature of 3000 K reached within seconds at a rate of ∼105 K per second) in an aqueous solution under an ultrasonic field (40 kHz). Illustrating the effectiveness of this approach, the CuAgNiFeCoRuMn@MgO-P3000 catalyst exhibited exceptional catalytic efficiency in selective hydrogenation of nitro compounds, with over 99% chemoselectivity and nearly 100% conversion within 60 s and no decrease in catalytic activity even after 40 cycles (>98% conversion in 120 s). Our results provide an effective, transferable method for rationally designing supported MEA-NP catalysts at the atomic level and pave the way for a wide variety of catalytic reactions.
The detection of puerarin concentration is an essential capability to study the functional role of the Pueraria root as a natural medicine and dietary source in the treatment of cardiovascular diseases and liver protection. Current methods to detect and measure puerarin concentration, such as ultraviolet–visible spectrophotometry (UV), are bulky, require an external power supply, and are inconvenient to use. Here, we propose a triboelectric puerarin-detecting sensor (TPDS) which is based on liquid–solid contact electrification, in which liquid–solid interactions generate rapid electrical signals in only 0.4 ms to enable real-time detection of puerarin concentration in water droplets. The electrical signal of the TPDS decreases with an increase of puerarin concentration, and the sensitivity of the approach is 520 V·(µg/mL)–1. The TPDS represents a miniature and cost-effective sensor that is 0.2% of the size and 0.01% of the cost of a UV spectrophotometer. Our theoretical analysis verified that the puerarin concentration in droplets can effectively regulate the electronic structure, where higher concentrations of puerarin lead to a narrower energy bandgap, which allows the TPDS to detect puerarin concentration without the need for an external power supply. The TPDS therefore provides a route for the development of a portable and self-powered method to measure the concentration of an active ingredient in droplets through the conversion of natural energy.
Substance discrimination beyond the shape feature is urgently desired for x-ray imaging for enhancing target identification. With two x-ray sources or stacked two detectors, the two-energy-channel x-ray detection can discriminate substance density by normalizing the target thickness. Nevertheless, the artifacts, high radiation dose and difficulty in image alignment due to two sources or two detectors impede their widespread application. In this work, we report a single direct x-ray detector with MAPbI3/MAPbBr3 heterojunction for switchable soft x-ray (<20 keV) and hard x-ray (>20 keV) detection under one x-ray source. Systematic characterizations confirm soft and hard x-ray deposit their energy in MAPbI3 and MAPbBr3 layer, respectively, while working voltages can control the collection of generated charge carriers in each layer for selective soft/hard x-ray detection. The switching rate between soft and hard x-ray detection mode reaches 100 Hz. Moreover, the detector possesses a moderate performance with ∼50 nGy s–1 in limit-of-detection, ∼8000 µC Gy–1 cm–2 in sensitivity and ∼7 lp/mm in imaging resolution. By defining the attenuation coefficient ratio (μL/μH) as substance label, we effectively mitigate the influence of target thickness and successfully discriminate substances in the acquired x-ray images.
Memristors have been emerging as promising candidates for computing systems in post-Moore applications, particularly electrochemical metallization-based memristors, which are poised to play a crucial role in neuromorphic computing and machine learning. These devices are favored for their high integration density, low power consumption, rapid switching speed, and significant on/off ratio. Despite advancements in various materials, achieving adequate electrical performance—characterized by threshold switching (TS) behavior, spontaneous reset, and low off-state resistance—remains challenging due to the limitations in conductance filament control within the nanoscale resistive switching layer. In this study, we introduce an efficient method to control the ZrO2 crystallinity for tunable volatility memristor by establishing the filament paths through a simple thermal treatment process in a single oxide layer. The effect of ZrO2 crystallinity to create localized filament paths for enhancing Ag migration and improving TS behavior is also investigated. In contrast to its amorphous counterpart, crystallized ZrO2 volatile memristor, treated by rapid thermal annealing, demonstrates a steep switching slope (0.21 mV dec–1), a high resistance state (25 GΩ), and forming-free characteristics. The superior volatile performance is attributed to localized conductive filaments along low-energy pathways, such as dislocations and grain boundaries. By coupling with enhanced volatile switching behavior, we believe that the volatility is finely tuned to function as short-term memory for reservoir computing, making it particularly well-suited for tasks such as audio and image recognition.
Amid the ongoing transition toward renewable fuels, the self-supported layered double hydroxides (LDHs) are envisioned as propitious electrocatalysts for reinvigorating the electrocatalysis realm, thereby facilitating environmental remediation and bolstering sustainable global energy security. Exploiting appealing attributes such as unique lamellar structure, abundant active sites, tunable intercalation spacing and compositional flexibility, LDHs boast remarkable activity, selectivity and stability across diverse energy-related applications. By virtue of addressing the technological and time prominence of excavating their renaissance, this review first encompasses the facile state-of-the-art synthetic approaches alongside intriguing modification strategies, toward deciphering the authentic structure–performance correlations for advancing more robust and precise catalyst design. Aside from this, heterostructure engineering employing diversified ranges of coupling materials is highlighted, to construct ground-breaking binder-free LDHs-based heterostructures endowing with unprecedented activity and stability. Subsequently, the milestone gained from experimental research and theoretical modeling of this frontier in multifarious electrocatalytic applications, including HER, OER, UOR, AOR, seawater splitting and other fundamental conversion reactions is rigorously unveiled. As a final note, a brief conclusion is presented with an outline of future prospects. Essentially, this review aspires to offer enlightenment and incite wise inspiration for the future evolution of innovative and resilient next-generation catalysts.
Recently, the intelligent strategies for adapting to multiple challengeable surfaces of electroactive programmable materials integrated with bio-inspired architectures offer expanded directions beyond traditional limitations in soft grippers, medical mobile robots, and XR (Extended Reality) interfaces. These electroactive programmable adhesive materials are adaptively designed for a variety of complex surfaces, including soft, wet, non-flat, or contamination-susceptible feature such as bio-surfaces and vulnerable objects. They can be produced via solution-based methods of replica coating or 3/4-dimensional printing. The integration of electroactive programmable materials and intelligent adhesive architecture enables super-adaptive switchable adhesion to a variety of complex surfaces through control of physical deformation and mechanical properties at the adhesive interface, presenting a breakthrough in soft electro-robotics and extended reality (XR) Haptic interfaces technology. These surface-adaptive platform can provide multiple functionalities that can efficiently control physical deformations of soft bioinspired architectures or transfer physical energy (heat, vibration, pressure) into the engaged surfaces in a lightweight and human-friendly form. This review focuses on intelligent strategies, principles, design, and fabrication methods of super-adaptive electroactive programmable materials intelligently combined with bioinspired switchable adhesives for next-generation human–robot interaction devices, along with current challenges and prospects.
Metal halide perovskites based on formamidinium (FA), or FA-rich compositions have shown great promise for high-performance photovoltaics. A deeper understanding of the impact of ambient conditions (e.g., moisture, oxygen, and illumination) on the possible reactions of FA-based perovskite films and their processing sensitivities has become critical for further advances toward commercialization. Herein, we investigate reactions that take place on the surface of the FA0.7Cs0.3, mixed Br/I wide bandgap perovskite thin films in the presence of humid air and ambient illumination. The treatment forms a surface layer containing O, OH, and N-based anions. We propose the latter originates from formamidine trapped at the perovskite/oxide interface reacting further to cyanide and/or formamidinate—an understudied class of pseudohalides that bind to Pb. Optimized treatment conditions improve photoluminescence quantum yield owing to both reduced surface recombination velocity and increased bulk carrier lifetime. The corresponding perovskite solar cells also exhibit improved performance. Identifying these reactions opens possibilities for better utilizing cyanide and amidinate ligands, species that may be expected during vapor processing of FA-based perovskites. Our work also provides new insights into the self-healing or self-passivating of MA-free perovskite compositions where FA and iodide damage could be partially offset by advantageous reaction byproducts.