Bright Lead-Free Inorganic CsSnBr<sub>3</sub> Perovskite Light-Emitting Diodes
Jung‐Min Heo, Himchan Cho, Seong‐Chul Lee, Minho Park, Joo Sung Kim, Hobeom Kim, Jinwoo Park, Young‐Hoon Kim, Hyung Joong Yun, Eojin Yoon, Dong‐Hyeok Kim, Soyeong Ahn, Sung‐Joo Kwon, Chan‐Yul Park, Tae‐Woo Lee
Abstract
Tin-based perovskites have emerged as lead-free alternatives, but their application in perovskite light-emitting diodes (PeLEDs) has been limited due to the low chemical stability and inhomogeneity of the inorganic CsSnBr3 films using solution processing. Here, we demonstrate bright (∼160 cd m–2) CsSnBr3 PeLEDs made by introducing co-additives consisting of SnF2 and a grain-growth inhibitor (1,3,5-tris(N-phenylbenzimidazol-2-yl)benzene). The use of co-additives increased the number of nucleation sites during the crystallization process of CsSnBr3, and consequently yielded uniform CsSnBr3 films with decreased grain size and improved defect passivation. The crystallization-controlled CsSnBr3 PeLEDs had a maximum luminance of ∼160 cd m–2, i.e., ∼7500 times brighter than than that of the control devices (without additive, 0.02 cd m–2), and a long device lifetime of ∼30 h at 58 cd m–2. Our work suggests that control of the crystallization of CsSnBr3 during film formation is an important requirement to increase the luminescence efficiency and stability of tin-based PeLEDs.