February 26, according to the official website of the University of Science and Technology of China, Professor Xiao Zhengguo of the Physics Department of University of Science and Technology of China and the key Laboratory of strong Coupling lisng Quantum material Physics of the Chinese Academy of Sciences has made important progress in the preparation of large area sky blue perovskite LED. The research team successfully prepared a large area and high efficiency sky blue perovskite LED by scraping and coating supersaturated perovskite solution to regulate the nucleation growth process, which is an important step towards the commercial application of perovskite LED lighting. The related results, entitled "Large-area and efficient sky-blue perovskite light-emitting diodes via blade-coating", were published in the magazine Advanced Materials on February 18.
Metal halide perovskite LED has good electrical conductivity and can achieve high luminous brightness at low voltage, so it is an ideal choice for the next generation of energy-saving lighting. At present, the efficiency of red light and green light perovskite LED is very high, but the efficiency of sky blue light / blue light perovskite LED is relatively low, mainly because the crystallization process of sky blue light / blue light perovskite thin films is more difficult to control, resulting in poor film quality. At present, there is no large area of sky blue light perovskite LED related reports.
Fig. 1. Schematic diagram of crystallization of scraped supersaturated solution (a) and AFM diagram of perovskite film (b). JV and EQE curves (c), EL spectra and CIE diagrams (d) of small area PeLED devices (0.04 cm2). E, PL photos of large area perovskite films. F, photos of large area PeLED devices (28 cm2) working.
On the basis of the work done by Xiao Zhengguo's research group on the preparation of large area and high efficiency red light perovskite LED (Nat. Commun.12, 147,2021), adjust the composition of perovskite CsPb (Br0.84Cl0.16) 3, and add additional amine halide additive to limit the growth of perovskite grains and passivate defects to achieve sky blue emission. At the same time, a more volatile and supersaturated perovskite precursor solution is obtained by partially replacing DMSO with DMF. In the scraping process, perovskite nuclei precipitate directly from the supersaturated solution, which can effectively increase the crystal nucleus density and shorten the process of crystal nucleus growth, thus preparing uniform and dense perovskite thin films with small grains, as shown in Fig. 1A and b. The external quantum efficiency of the azure light perovskite LED prepared by scraping method is 10.3%. The peak position of the pencil El is 489 nm, and the color coordinate is (0.071, 0.294). At the same time, the luminous uniformity and brightness of large area perovskite LED (28 cm2) are very good.
Professor Xiao Zhengguo of the Physics Department of the University of Science and Technology of China is the correspondent author of the paper, and Chu Shenglong, a doctoral student in the physics department, is the first author of the paper. This research is supported by the National Natural Science Foundation of China, the talent team project of China University of Science and Technology and the special fund for basic scientific research business fees of central universities.