1. One-step fabrication of ZnO electron-transporting layers for perovskite light-emitting diodes with sub-bandgap turn-on voltage.
- Author
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Sun, Xinzhi, Bai, Jialin, Wang, Ting, Zhang, Hanzhuang, and Ji, Wenyu
- Subjects
LIGHT emitting diodes ,PEROVSKITE ,ELECTRON field emission ,ZINC oxide ,VOLTAGE ,CHARGE injection ,ELECTRON transport - Abstract
Efficient charge injection into the emitters, which can reduce the voltage loss at interfaces, is a prerequisite for high-performance light-emitting diodes, with low voltage operation. Here we develop a sol–gel ZnO (s-ZnO) electron-transport layer for the perovskite light-emitting diodes (PeLEDs) with green-emission formamidinium lead bromide (FAPbBr
3 ) perovskites as emitters. Polyethylenimine (PEI) is mixed into the s-ZnO precursor as a modifier, which not only promotes the wettability of s-ZnO films, but also passivates the defects of s-ZnO without sacrificing their electrical conductivity. As a result, highly efficient FAPbBr3 films are obtained on the s-ZnO films. The maximum current efficiency of PeLED with s-ZnO:PEI electron-transporting layer reaches 13.5 cd/A, 45% higher than that based on pristine s-ZnO without PEI modifier. Benefiting from the outstanding charge-transport properties of s-ZnO and high-quality perovskite film, the turn-on voltage of the s-ZnO based PeLEDs is only 1.9 V, much lower than the band-gap voltage (~ 2.3 V) of FAPbBr3 . [ABSTRACT FROM AUTHOR]- Published
- 2024
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