Bio-Inspired Pangolin Design for Self-Healable Flexible Perovskite Light-Emitting Diodes
Xiaoyan Qian, Yang Shen, Liu-Jiang Zhang, Minglei Guo, Xiao‐Yi Cai, Yu Lu, Huimin Liu, Ye-Fan Zhang, Yan‐Qing Tang, Li Chen, Yingyi Tang, Jingkun Wang, Wei Zhou, Xingyu Gao, Hongying Mao, Yanqing Li, Jianxin Tang, Shuit‐Tong Lee
Abstract
Despite tremendous developments in the luminescene performance of perovskite light-emitting diodes (PeLEDs), the brittle nature of perovskite crystals and their poor crystallinity on flexible substrates inevitably lead to inferior performance. Inspired by pangolins' combination of rigid scales and soft flesh, we propose a bionic structure design for self-healing flexible PeLEDs by employing a polymer-assisted crystal regulation method with a soft elastomer of diphenylmethane diisocyanate polyurethane (MDI-PU). The crystallinity and flexural strain resistance of such perovskite films on plastics with silver-nanowire-based flexible transparent electrodes are highly enhanced. The detrimental cracks induced during repeated deformation can be effectively self-healed under heat treatment via intramolecular/intermolecular hydrogen bonds with MDI-PU. Upon collective optimization of the perovskite films and device architecture, the blue-emitting flexible PeLEDs can achieve a record external quantum efficiency of 13.5% and high resistance to flexural strain, which retain 87.8 and 80.7% of their initial efficiency after repeated bending and twisting operations of 2000 cycles, respectively.