Bright Lead-Free Inorganic CsSnBr 3 Perovskite Light-Emitting Diodes

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 CsSnBr 3 films using solution processing. Here, we demonstrate bright (∼160 cd m –2 ) CsSnBr 3 PeLEDs made by introducing co-additives consisting of SnF 2 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 CsSnBr 3, and consequently yielded uniform CsSnBr 3 films with decreased grain size and improved defect passivation. The crystallization-controlled CsSnBr 3 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 CsSnBr 3 during film formation is an important requirement to increase the luminescence efficiency and stability of tin-based PeLEDs.