Self-defect-passivation by Br-enrichment in FA-doped Cs1−xFAxPbBr3 quantum dots: towards high-performance quantum dot light-emitting diodes

October 7, 2020

Title

Self-defect-passivation by Br-enrichment in FA-doped Cs1−xFAxPbBr3 quantum dots: towards high-performance quantum dot light-emitting diodes

Author

Young Ran Park, Sangwon Eom, Hong Hee Kim, Won Kook Choi & Youngjong Kan

Year

2020

Journal

Scientific Reports volume 10, Article number: 14758 (2020)

Abstract

Halide vacancy defect is one of the major origins of non-radiative recombination in the lead halide perovskite light emitting devices (LEDs). Hence the defect passivation is highly demanded for the high-performance perovskite LEDs. Here, we demonstrated that FA doping led to the enrichment of Br in Cs1−xFAxPbBr3 QDs. Due to the defect passivation by the enriched Br, the trap density in Cs1−xFAxPbBr3 significantly decreased after FA doping, and which improved the optical properties of Cs1−xFAxPbBr3 QDs and their QD-LEDs. PLQY of Cs1−xFAxPbBr3 QDs increased from 76.8% (x = 0) to 85.1% (x = 0.04), and Lmax and CEmax of Cs1−xFAxPbBr3 QD-LEDs were improved from Lmax = 2880 cd m−2 and CEmax = 1.98 cd A−1 (x = 0) to Lmax = 5200 cd m−2 and CEmax = 3.87 cd A−1 (x = 0.04). Cs1−xFAxPbBr3 QD-LED device structure was optimized by using PVK as a HTL and ZnO modified with b-PEI as an ETL. The energy band diagram of Cs1−xFAxPbBr3 QD-LEDs deduced by UPS analyses.

Instrument

FP-8500

Keywords

photoluminescence quantum yield, fluorescence, quantum dot light-emitting diodes< LEDs