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Herein, we report the fabrication of high-performance transparent quantum-dot light-emitting diodes (Tr-QLEDs) with ZnO/ZnMgO inorganic double electron-transport layers (ETLs). The ETLs effectively suppress the excess electron injection and facilitate charge balance in the Tr-QLEDs. The thick ETLs as buffer layers can also withstand the plasma-induced damage during the indium tin oxide sputtering. These factors collectively contribute to the development of Tr-QLEDs with improved performance. As a result, our Tr-QLEDs with double ETLs exhibited a high transmittance of 82% at 550 nm and a record external quantum efficiency of 11.8%, which is 1.27 times higher than that of the devices with pure ZnO ETL. These results indicate that the developed ZnO/ZnMgO inorganic double ETLs could offer promising solutions for realizing high-efficiency Tr-QLEDs for next-generation display devices.

Transparent quantum-dot light-emitting diodes (Tr-QLEDs) with an inverted architecture has been developed. The inverted Tr-QLEDs are designed for integrating with thin-film transistors (TFTs) circuit easily. The 1,4,5,8,9,11-hexaazatriphenylenehexacarbonitrile (HAT-CN) is employed as a hole injection layer (HIL) as well as a buffer layer in the inverted Tr-QLEDs. An optimized HAT-CN as dual-functional modified layer facilitates charge injection balance and meanwhile reduces the plasma damage caused by sputtering process. High performance device with a peak current efficiency (CE) and maximum external quantum efficiency (EQE) of 14.7 cd/A and 11.3% was obtained, wherein the EQE is the highest record for Tr-QLEDs. The transmittance of the Tr-QLEDs at 550 nm reached up to 78%. These Tr-QLEDs possess potential for the next-generation transparent displays applications.

Lead halide perovskite is a new photovoltaic material with excellent material characteristics, such as high optical absorption coefficient, long carrier transmission length, long carrier lifetime and low defect state density. At present, the steady-state photoelectric conversion efficiency of all-perovskite laminated cells is as high as 28.0%, which has surpassed the highest efficiency of monocrystalline silicon cells (26.7%). In addition to its excellent photovoltaic properties, perovskite is also a type of direct bandgap semiconductor with low cost, solubilization, high fluorescence quantum efficiency and tunable radiation wavelength, which brings hope for the realization of electrically pumped low-cost semiconductor lasers. In recent years, a variety of perovskite lasers have emerged, ranging from the type of resonator, the wavelength and pulse width of the pump source, and the preparation process. However, the current research on perovskite lasers is only about the type of resonator, the type of perovskite and the pump wavelength, but the performance of the laser itself and the practical application of perovskite lasers are still in the initial stages. In this review, we summarize the recent developments and progress of solution-processed perovskite semiconductors lasers. We discuss the merit of solution-processed perovskite semiconductors as lasing gain materials and summarized the characteristics of a variety of perovskite lasers. In addition, in view of the issues of poor stability and high current density required to achieve electrically pumped lasers in perovskite lasers, the development trend of perovskite lasers in the future is prospected.