Realizing High Brightness Quasi-2D Perovskite Light-emitting Diodes with Reduced Efficiency Roll-off via Multifunctional Interface Engineering
Yu-Kuan Lin, Chiung-Han Chen, Yen-Yu Wang, Ming-Hsuan Yu, Jing-Wei Yang, I-Chih Ni, Bi-Hsuan Lin, Ivan S. Zhidkov, Ernst Z. Kurmaev, Yu-Jung Lu*, and Chu-Chen Chueh*
2023/12/31
Quasi-2D perovskites have recently flourished in the field of luminescence due to the quantum-confinement effect and the efficient energy transfer between different n phases resulting in exceptional optical properties. However, owing to the lower conductivity and poor charge injection, quasi-2D perovskite light-emitting diodes (PeLEDs) typically suffer from low brightness and high-efficiency roll-off at high current densities compared to 3D perovskite-based PeLEDs, which is undoubtedly one of the most critical issues in this field. In this work, quasi-2D PeLEDs with high brightness, reduced trap density, and low-efficiency roll-off are successfully demonstrated by introducing a thin layer of conductive phosphine oxide at the perovskite/electron transport layer interface. The results surprisingly show that this additional layer does not improve the energy transfer between multiple quasi-2D phases in the perovskite film, but purely improves the electronic properties of the perovskite interface. On the one hand, it passivates the surface defects of the perovskite film; on the other hand, it promotes electron injection and prevents hole leakage across this interface. As a result, the modified quasi-2D pure Cs-based device shows a maximum brightness of > 70,000 cd m−2 (twice that of the control device), a maximum external quantum efficiency (EQE) of > 10% and a much lower efficiency roll-off at high bias voltages.
Research Highlights
