Perovskite light-emitting diodes (PeLEDs), because of its fundamental scientific importance and practical applications in the fields of low-cost light source or display applications, have drawn worldwide attention in recent years. However, PeLEDs available today suffer from a compromise in their emission efficiency and operation stability. In this study, we designed and fabricated a stacking all-inorganic multilayer structure by using inorganic perovskite CsPbBr quantum dots (QDs) as the emissive layer and inorganic n-type MgZnO and p-type MgNiO as the carrier injectors, respectively. Through energy band engineering of carrier injectors by Mg incorporation and their thickness optimization, PeLEDs with maximum luminance of 3809 cd/m, luminous efficiency of 2.25 cd/A, and external quantum efficiency of 2.39% have been realized, which are much better than most PeLEDs from CHNHPbBr films, and comparable with the highest results reported on CsPbBr QDs LEDs. More importantly, the unencapsulated PeLEDs in a continuous current mode demonstrate a remarkable operation stability against water and oxygen degradation. After a continuous operation for 10 h under a dc bias (10.0 V), nearly 80% of the original efficiency of the PeLEDs has been retained, greatly superior to reference and other previously reported devices constructed with conventional organic carrier injectors. Our results obtained open possibilities for the design and development of high-efficiency and air-stable PeLEDs that are not dependent on expensive and less-stable organic carrier injectors.

Recently, a pressing requirement of solid-state lighting sources with high performance and low cost has motivated increasing research in metal halide perovskites. However, the relatively low emission efficiency and poor operation stability of perovskite light-emitting diodes (LEDs) are still critical drawbacks. In this study, a strategy of solution-processed all-inorganic heterostructure was proposed to overcome the emission efficiency and operation stability issues facing the challenges of perovskite LEDs. Solution-processed n-ZnO nanoparticles and p-NiO are used as the carrier injectors to fabricate all-inorganic heterostructured CsPbBr quantum dot LEDs, and a high-efficiency green emission is achieved with maximum luminance of 6093.2 cd/m, external quantum efficiency of 3.79%, and current efficiency of 7.96 cd/A. More importantly, the studied perovskite LEDs possess a good operation stability after a long test time in air ambient. Typically, the devices can endure a high humidity (75%, 12 h) and a high working temperature (393 K, three heating/cooling cycles) even without encapsulation, and the operation stability is better than any previous reports. It is anticipated that this work will provide an effective strategy for the fabrication of high-performance perovskite LEDs with good stability under ambient and harsh conditions, making practical applications of such LEDs a real possibility.

The high-performance broadband photodetectors have attracted intensive scientific interests due to their potential applications in optoelectronic systems. Despite great achievements in two-dimensional (2D) materials based photodetectors such as graphene and black phosphorus, obvious disadvantages such as low optical absorbance and instability preclude their usage for the broadband photodetectors with the desired performance. An alternative approach is to find promising 2D materials and fabricate heterojunction structures for multifunctional hybrid photodetectors. In this work, 2D WS 2 /Si heterojunction with a type-II band alignment is formed in situ. This heterojunction device produced a high I on /I off ratio over 10, 6 responsivity of 224 mA/W, specific detectivity of 1.5 × 10 12 Jones, high polarization sensitivity, and broadband response up to 3043 nm. Furthermore, a 4 × 4 device array of WS 2 /Si heterojunction device is demonstrated with high stability and reproducibility. These results suggest that the WS 2 /Si type-II heterojunction is an ideal photodetector in broadband detection and integrated optoelectronic system.

High-performance perovskite photodetectors based on solution-processed all-inorganic CsPbBr3 thin films were fabricated with a high photoresponsivity and on/off photocurrent ratio.

High-performance and air-stable perovskite photodetectors were fabricated using lead-free double perovskite Cs2AgBiBr6 thin films as light absorbers.

The research of ultraviolet photodetectors (UV PDs) have been attracting extensive attention, due to their important applications in many areas. In this study, PtSe 2 /GaN heterojunction is in-situ fabricated by synthesis of large-area vertically standing two-dimensional (2D) PtSe 2 film on n-GaN substrate. The PtSe 2 /GaN heterojunction device demonstrates excellent photoresponse properties under illumination by deep UV light of 265 nm at zero bias voltage. Further analysis reveals that a high responsivity of 193 mA•W-1 , an ultrahigh specific detectivity of 3.8 × 10 14 Jones, linear dynamic range of 155 dB and current on/off ratio of ~ 10 8 , as well as fast response speeds of 45/102 μs were obtained at zero bias voltage. Moreover, this device response quickly to the pulse laser of 266 nm with a rise time of 172 ns. Such high-performance PtSe 2 /GaN heterojunction UV PD demonstrated in this work is far superior to previously reported results, suggesting that it has great potential for deep UV detection.

Self-powered MoS2/GaN p–n heterojunction photodetectors exhibited high sensitivity to deep-UV light with high responsivity, specific detectivity and fast response speeds.

This work presents a strategy of combining the concepts of localized surface plasmons (LSPs) and core/shell nanostructure configuration in a single perovskite light-emitting diode (PeLED) to addresses simultaneously the emission efficiency and stability issues facing current PeLEDs' challenges. Wide bandgap n-ZnO nanowires and p-NiO are employed as the carrier injectors, and also the bottom/upper protection layers to construct coaxial core/shell heterostructured CsPbBr 3 quantum dots LEDs. Through embedding plasmonic Au nanoparticles into the device and thickness optimization of the MgZnO spacer layer, an emission enhancement ratio of 1.55 is achieved. The best-performing plasmonic PeLED reaches up a luminance of 10 206 cd m −2 , an external quantum efficiency of ≈4.626%, and a current efficiency of 8.736 cd A −1 . The underlying mechanisms for electroluminescence enhancement are associated with the increased spontaneous emission rate and improved internal quantum efficiency induced by exciton-LSP coupling. More importantly, the proposed PeLEDs, even without encapsulation, present a substantially improved operation stability against water and oxygen degradation (30-day storage in air ambient, 85% humidity) compared with any previous reports. It is believed that the experimental results obtained will provide an effective strategy to enhance the performance of PeLEDs, which may push forward the application of such kind of LEDs.