Perovskite LED was prepared by new technology

Large area perovskite LED was prepared by new technology. Xiao Zhengguo, a professor at the University of Science and Technology of China (USTC), and his team recently produced large-area, high-efficiency perovskite light-emitting diodes (LEDs) using an air-knife-assisted scraping and coating method, which is an important step towards commercial application.The results were recently published in Nature Communications.

As a new generation of LED devices, metal halide perovskite LED has the advantages of wide color gamut and easy preparation.In 2014, perovskite LEDs that emit light at room temperature were first reported to have an external quantum efficiency (EQE) of less than 1%.After just a few years of development, its efficiency has exceeded 20%, close to the level of commercial organic LEDs, showing a broad application prospect in lighting and display fields.However, the current high efficiency perovskite LEDs are based on the spin coating method, the device area is very small, can not meet the needs of large commercial lighting.

Scratching method is a method to prepare large-area thin films based on solution method, but the crystallization process of perovskite thin films prepared by scraping method is not easy to control, and the EQE of the perovskite LED prepared by scraping method is only 1.1% at most, and the device area is also very limited.

XiaoZhengGuo group in organic inorganic hybrid perovskite as the research object, by reducing the perovskite liquid precursor concentrations, 4 - fluorine benzene methylamine, introducing auxiliary method combined with the air knife, make the film crystallization process to form more nucleation sites, which were uniform density of perovskite polycrystalline thin film, the surface roughness of the film is only 0.8 nm.The large area perovskite thin film (6 cm ×9 cm) prepared by the scatch-coating method shows excellent uniformity in terms of thickness, surface roughness, fluorescence yield, fluorescence lifetime, etc. The highest EQE of the device reaches 16.1%, and the ultra-large perovskite LED emits very uniform red light when working.