Bright Lead-Free Inorganic CsSnBr₃ Perovskite Light-Emitting Diodes

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.