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.

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

We demonstrated a stable and spectrum-selective self-powered UV photodetector based on lead-free Cs3Cu2I5 films with excellent photodetection performance.

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.

CsPbBr3 QDs/silica composites with substantially improved stability were applied as the color-converting layer for high-performance white LED fabrication.

Recently, metal halide perovskites have attracted tremendous research interest due to their exceptional optoelectronic properties, showing great application potentials in the fields of solar cells, light-emitting diodes, and photodetectors. However, most of the previously reported perovskite photodetectors are based on the polycrystalline perovskite films, and the amounts of defects and large grain boundaries in the films are unfavorable for further improvement of the performance of the device. In this study, highquality CsPbCl 3 microwire networks (MWNs) were successfully prepared by a vapor-phase method. By changing the evaporation temperature of source powders, a series of MWs with different widths and coverage can be obtained. Ag electrodes were thermally deposited onto the surface of the mica substrate through a shadow mask, and symmetrically structured photoconductive detectors were fabricated. The performance of the studied photodetector is remarkable in terms of its high on/off photocurrent ratio of 2.0 × 10 3 , a photoresponsivity of 14.3 mA/ W, and a fast response speed of 3.212/2.511 ms. It is worth noting that the fast varying optical signal can be detected, even at a high frequency of 3500 Hz. More importantly, the proposed CsPbCl 3 MWN photodetectors without encapsulation demonstrate a remarkable operation stability over the test in air ambient, can withstand a high working temperature of 373 K for 9 h continuous operation, and nearly 70% of the original photocurrent of the photodetectors has been retained, further confirming the ultrastable device operation. Note that this is the first report on high-temperature operation behaviors of perovskite photodetectors. The results in this study may promote the development of stable and high-efficiency perovskites photodetectors compatibility for practical applications under harsh conditions.

Self-powered solar-blind ultraviolet (UV) photodetectors have drawn worldwide attention in recent years because of their important applications in military and civilian areas. In this study, a dual-source vapor codeposition technique was employed, for the first time, to prepare a nontoxic copper halide Cs 3 Cu 2 I 5 , which was integrated with the β-Ga 2 O 3 wafer to construct a type-II heterojunction for photodetection applications. By optimizing the annealing conditions, high-quality Cs 3 Cu 2 I 5 films with dense morphology, high crystallinity, and a long carrier lifetime of 1.02 μs were acquired. Because of the high material integrity of Cs 3 Cu 2 I 5 films and effective interfacial carrier transfer from Cs 3 Cu 2 I 5 to β-Ga 2 O 3 , a heterojunction device demonstrates a good solar-blind UV response property and operates at zero bias. Typically, the photodetector presents a low dark current (∼1.2 pA), a high solar-blind/ UVA rejection ratio (∼1.0 × 10 3 ), a relatively fast photoresponse speed (37/45 ms), and a high photo-to-dark current ratio (∼5.1 × 10 4 ) at zero bias. Moreover, even after 12-h continuous working and 2-month storage without encapsulation in ambient air, the photodetection ability of the device can almost be maintained, demonstrating outstanding air stability. Our results suggest that nontoxic Cs 3 Cu 2 I 5 is able to serve as a prospective candidate for stable solar-blind UV photodetection.

We present a review of the recent advances in environment-friendly photodetectors based on lead-free metal halide perovskites and perovskite derivatives.