High-Performance
All-Inorganic Architecture Perovskite
Light-Emitting Diodes Based on Tens-of-Nanometers-Sized CsPbBr3 Emitters in a Carrier-Confined Heterostructure
posted on 2024-03-12, 21:12authored byXinquan Gong, Xiaoming Hao, Junjie Si, Yunzhou Deng, Kai An, Qianqing Hu, Qiuting Cai, Yun Gao, You Ke, Nana Wang, Zhuopeng Du, Muzhi Cai, Zhizhen Ye, Xingliang Dai, Zugang Liu
Developing
green perovskite light-emitting diodes (PeLEDs) with
a high external quantum efficiency (EQE) and low efficiency roll-off
at high brightness remains a critical challenge. Nanostructured emitter-based
devices have shown high efficiency but restricted ascending luminance
at high current densities, while devices based on large-sized crystals
exhibit low efficiency roll-off but face great challenges to high
efficiency. Herein, we develop an all-inorganic device architecture
combined with utilizing tens-of-nanometers-sized CsPbBr3 (TNS-CsPbBr3) emitters in a carrier-confined heterostructure
to realize green PeLEDs that exhibit high EQEs and low efficiency
roll-off. A typical type-I heterojunction containing TNS-CsPbBr3 crystals and wide-bandgap Cs4PbBr6 within
a grain is formed by carefully controlling the precursor ratio. These
heterostructured TNS-CsPbBr3 emitters simultaneously enhance
carrier confinement and retain low Auger recombination under a large
injected carrier density. Benefiting from a simple device architecture
consisting of an emissive layer and an oxide electron-transporting
layer, the PeLEDs exhibit a sub-bandgap turn-on voltage of 2.0 V and
steeply rising luminance. In consequence, we achieved green PeLEDs
demonstrating a peak EQE of 17.0% at the brightness of 36,000 cd m–2, and the EQE remained at 15.7% and 12.6% at the brightness
of 100,000 and 200,000 cd m–2, respectively. In
addition, our results underscore the role of interface degradation
during device operation as a factor in device failure.