Hydrogen Bond-Assisted Dual Passivation for Blue Perovskite Light-Emitting Diodes
Zhongkai Yu, Xinyu Shen, Xiangyang Fan, Young‐Kwang Jung, Woo Hyeon Jeong, Akash Dasgupta, Manuel Kober‐Czerny, Pietro Caprioglio, Sung Heum Park, Hyosung Choi, Henry J. Snaith, Samuel D. Stranks, Bo Ram Lee
Abstract
Although significant progress has been made in the development of green, red, and near-infrared perovskite light-emitting diodes (PeLEDs), blue PeLEDs exhibit inferior performance, owing to various defects and poor carrier injection in solution-processed perovskite films. Thus, this study incorporates dual-passivation additive diphenylphosphinamide (DPPA) into perovskite films, and through density functional theory calculations and experimental characterizations, DPPA has been proven to be an effective passivator. Its phosphine oxide group coordinates with unsaturated lead ions, passivating perovskite defects, while the amino group forms hydrogen bonds with adjacent halide ions, suppressing their migration and further strengthening the passivation effect. Blue quasi-two-dimensional PeLEDs based on DPPA-modified perovskite films achieved an external quantum efficiency of 12.31% with an emission peak at 486 nm. Moreover, the device operational lifetime was extended by 32% with more stable spectra owing to the decreased defect density and suppressed ion migration in the perovskite film.