am0c06737_si_001.pdf (664.48 kB)
Ion Migration-Induced Degradation and Efficiency Roll-off in Quasi-2D Perovskite Light-Emitting Diodes
journal contribution
posted on 2020-07-07, 14:33 authored by Tai Cheng, Ganbaatar Tumen-Ulzii, Dino Klotz, Satoru Watanabe, Toshinori Matsushima, Chihaya AdachiQuasi-2D
perovskites have attracted wide attention as the emitter of light-emitting
diodes (LEDs) in recent years because of the ease of obtaining high
external quantum efficiencies (EQEs). However, the quick degradation
under continuous operation and significant EQE roll-off at high current
densities are issues that need to be overcome for future practical
applications using quasi-2D perovskite LEDs (PeLEDs). In this context,
we discuss the mechanism of the degradation and EQE roll-off on the
basis of ion migration. The migration of ligand cations though domain
boundaries of quasi-2D perovskite films induces the gradual loss of
defect passivation at the boundaries, which results in the reversible
PeLED degradation and severe EQE roll-off. When the device operation
time is long, the mobile cations enter and interact with the electron
transport layer, leading to the stage of irreversible PeLED degradation.
The device degradation mechanisms we discovered here are constructive
for developing quasi-2D PeLEDs with better operational durability.