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 enabling low manufacturing costs, the propensity for defect formation with solution-based processing has led to an increasing need for defect passivation of perovskites. Here, we present an inexpensive and facile method to remedy surface defects through a post-deposition treatment process using branched alkylammonium cation species. The simultaneous realignment of interfacial energy levels on incorporation of tetraethylammonium bromide onto the surface of CH3NH3PbBr3 films contributes favourably towards the enhancement in overall light-emitting diode characteristics, achieving maximum luminance, current efficiency and EQE values of 11, 000 cd m-2, 0.68 cd A-1 and 0.16% respectively.