Grain Size Modulation and Interfacial Engineering of CH₃NH₃PbBr₃ Emitter Films through Incorporation of Tetraethylammonium Bromide

Metal halide perovskites have demonstrated breakthrough performances as absorber and emitter materials for photovoltaic and display applications respectively. However, despite the low manufacturing cost associated with solution-based processing, the propensity for defect formation with this technique has led to an increasing need for defect passivation. Here, we present an inexpensive and facile method to remedy surface defects through a postdeposition treatment process using branched alkylammonium cation species. The simultaneous realignment of interfacial energy levels upon incorporation of tetraethylammonium bromide onto the surface of CH₃NH₃PbBr₃ films contributes favorably toward the enhancement in overall light-emitting diode characteristics, achieving maximum luminance, current efficiency, and external quantum efficiency values of 11 000 cd m⁻², 0.68 cd A⁻¹, and 0.16 %, respectively.