Energetic Disorder Mitigation of Hole-Transport Layers via Molecular Assembly Boosts Charge Transport to Unlock Efficient and Stable Perovskite Light-Emitting Devices

作者：Zhao Luo, Weijia Zheng, Yulu Hua, Jianxun Wang, Shuo Li, Yingtong Zhou, Ziqi Song, Zeyu Miao, Zhou Jiang, Xinyan Zhou, Jingyu Qian, Jiaqi Zhang, Wenxu Yin, Haibo Wang, Wei Zhang, Xiaoyu Zhang · 发表于：Nano Letters · 年份：2025 · DOI：10.1021/acs.nanolett.5c04553 · 被引用次数：3 · 研究领域：Perovskite Materials and Applications、Organic Light-Emitting Diodes Research、Organic Electronics and Photovoltaics

Inadequate understanding and poor control of energetic disorder in polymer charge-transport layers pose a significant barrier to the device efficiency and stability of a perovskite light-emitting diode (PeLED). Here, we report a molecular monolayer engineering strategy to reduce the energetic disorder of poly(9-vinylcarbazole) (PVK), a widely used hole-transport material. By introducing a self-assembled monolayer (SAM) of [2-(9 H -carbazol-9-yl)ethyl]phosphonic acid (2PACz), we promote ordered π–π stacking in the overlying PVK film, resulting in prolonged coherence lengths, as demonstrated by grazing-incidence wide-angle X-ray scattering. We adapted ultraviolet photoelectron spectroscopy and an energy-resolved electrochemical impedance spectroscopy approach, which reliably tracks energetic disorders. PeLEDs employing SAM-modified PVK layers exhibit significantly improved external quantum efficiency (EQE) of 30.4% and a 9-fold prolonged operational lifetime. The successful application to blue PeLEDs (λ = 485 nm; EQE improved from 15.5% to 25.3%) underscores the broad applicability of this disorder-engineering strategy across diverse emitters.