Very efficient green light-emitting diodes based on polycrystalline CH(NH3)2PbBr3 film achieved by regulating precursor concentration and employing novel anti-solvent.

Formamidinium lead halide CH(NH 3 ) 2 PbX 3 (FAPbX 3 ) perovskite materials have achieved significant progress in efficient and stable single-junction/tandem perovskite solar cells, which is due to the promising thermal and air stability features. However, successful application of these materials in perovskite light-emitting diodes (PeLEDs) is scarce. Herein, regulating the FABr:PbBr 2 precursor concentration procedure is utilized to prepare very efficient PeLEDs based on CH(NH 3 ) 2 PbBr 3 (FAPbBr 3 ). The resultant FAPbBr 3 film prepared at optimized 10 wt% condition shows the satisfied exciton radiative rate and low nonradiative rate, and a high photoluminescent quantum yield. In combination with novel ethyl acetate (EA) anti-solvent spin-washing method, the resultant FAPbBr 3 film shows compact, uniform and high coverage morphology characteristics. The PeLEDs show a maximum current efficiency of 13.4 cd A −1 , an external quantum efficiency of 3.5%, a maximum luminance close to 10000 cd m −2 , and an extremely high power efficiency of 19.1 lm W −1 , respectively. This performance is the best among all reported on FAPbBr 3 type PeLEDs. [ABSTRACT FROM AUTHOR]