Realizing High Brightness Quasi-2D Perovskite Light-Emitting Diodes with Reduced Efficiency Roll-Off via Multifunctional Interface Engineering
Journal
Advanced Science
Date Issued
2023-01-01
Author(s)
Lin, Yu Kuan
Chen, Chiung Han
Wang, Yen Yu
Yu, Ming Hsuan
Yang, Jing Wei
Ni, I. Chih
Lin, Bi Hsuan
Zhidkov, Ivan S.
Kurmaev, Ernst Z.
Lu, Yu Jung
Abstract
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.
Subjects
efficiency roll-off | hole blocking | interface engineering | Light-emitting diodes | quasi-2D perovskites
SDGs
Type
journal article