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Sodium bromide additive improved film morphology and performance in perovskite light-emitting diodes

2017; American Institute of Physics; Volume: 111; Issue: 5 Linguagem: Inglês

10.1063/1.4997325

1520-8842

Jinghai Li, Feilong Cai, Liyan Yang, Fanghao Ye, Jinghui Zhang, Robert S. Gurney, Dan Liu, Tao Wang,

Organic Light-Emitting Diodes Research

Organometal halide perovskite is a promising material to fabricate light-emitting diodes (LEDs) via solution processing due to its exceptional optoelectronic properties. However, incomplete precursor conversion and various defect states in the perovskite light-emitting layer lead to low luminance and external quantum efficiency of perovskite LEDs. We show here the addition of an optimum amount of sodium bromide in the methylammonium lead bromide (MAPbBr3) precursor during a one-step perovskite solution casting process can effectively improve the film coverage, enhance the crystallinity, and passivate ionic defects on the surface of MAPbBr3 crystal grains, resulting in LEDs with a reduced turn-on voltage from 2.8 to 2.3 V and an enhanced maximum luminance from 1059 to 6942 Cd/m2 when comparing with the pristine perovskite-based device.