Proton-transfer-induced 3D/2D hybrid perovskites suppress ion migration and reduce luminance overshoot
Hobeom Kim, Joo Sung Kim, Jung‐Min Heo, Mingyuan Pei, In‐Hyeok Park, Zhun Liu, Hyung Joong Yun, Min Ho Park, Su-Hun Jeong, Young‐Hoon Kim, Jinwoo Park, Emad Oveisi, Satyawan Nagane, Aditya Sadhanala, Lijun Zhang, Jin Jung Kweon, Sung Keun Lee, Hoichang Yang, Hyun M. Jang, Richard H. Friend, Kian Ping Loh, Mohammad Khaja Nazeeruddin, Nam‐Gyu Park, Tae‐Woo Lee
Abstract
Perovskite light-emitting diodes (PeLEDs) based on three-dimensional (3D) polycrystalline perovskites suffer from ion migration, which causes overshoot of luminance over time during operation and reduces its operational lifetime. Here, we demonstrate 3D/2D hybrid PeLEDs with extremely reduced luminance overshoot and 21 times longer operational lifetime than 3D PeLEDs. The luminance overshoot ratio of 3D/2D hybrid PeLED is only 7.4% which is greatly lower than that of 3D PeLED (150.4%). The 3D/2D hybrid perovskite is obtained by adding a small amount of neutral benzylamine to methylammonium lead bromide, which induces a proton transfer from methylammonium to benzylamine and enables crystallization of 2D perovskite without destroying the 3D phase. Benzylammonium in the perovskite lattice suppresses formation of deep-trap states and ion migration, thereby enhances both operating stability and luminous efficiency based on its retardation effect in reorientation.