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Efficient and Spectrally Stable Blue Perovskite Light‐Emitting Diodes Based on Potassium Passivated Nanocrystals
Author(s) -
Yang Fei,
Chen Hongting,
Zhang Rui,
Liu Xiaoke,
Zhang Weizhuo,
Zhang JiBin,
Gao Feng,
Wang Lei
Publication year - 2020
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201908760
Subject(s) - perovskite (structure) , materials science , nanocrystal , photoluminescence , halide , light emitting diode , diode , optoelectronics , blueshift , metal , quantum efficiency , alkali metal , nanotechnology , inorganic chemistry , chemical engineering , chemistry , engineering , metallurgy , organic chemistry
Metal halide perovskites have aroused tremendous interest in the past several years for their promising applications in display and lighting. However, the development of blue perovskite light‐emitting diodes (PeLEDs) still lags far behind that of their green and red cousins due to the difficulty in obtaining high‐quality blue perovskite emissive layers. In this study, a simple approach is conceived to improve the emission and electrical properties of blue perovskites. By introducing an alkali metal ion to occupy some sites of peripheral suspended organic ligands, the nonradiative recombination is suppressed, and, consequently, blue CsPb(Br/Cl) 3 nanocrystals with a high photoluminescence quantum efficiency of 38.4% are obtained. The introduced K + acts as a new type of metal ligand, which not only suppresses nonradiative pathways but also improves the charge carrier transport of the perovskite nanocrystals. With further engineering of the device structure to balance the charge injection rate, a spectrally stable and efficient blue PeLED with a maximum external quantum efficiency of 1.96% at the emission peak of 477 nm is fabricated.