Ionic-liquid induced enhanced performance of perovskite light-emitting diodes

Organic-inorganic hybrid perovskites (OIHP) have attained a fantastic vigilance as promising light-emitting materials because of their low-cost production via facile solution processing, high color purity and easily tunable bandgaps. Nevertheless, the fabrication of OIHP films for light-emitting diodes generally requires complicated post-treatments, such as anti-solvent dropping process, owing to poor film formation property of the solvent being used for film deposition. In this work, we employed an ionic liquid, methylammonium acetate (MAAc), as additive to optimize the growth of FAPbBr3 perovskite films via an anti-solvent free approach. The influence of MAAc on the crystallization kinetics of FAPbBr3 phase and optoelectronic properties of the resulting perovskite films is systematically investigated. Our results demonstrate that MAAc is an effective modifier to attain perovskite films with reduced grain size, homogeneous grain distribution and smooth surface thereby leading to enhanced average lifetime of the excitons. Perovskite light-emitting diodes (PeLEDs) containing FAPbBr3 films obtained via incorporating 10 vol% MAAc as additive exhibited considerably suppressed leakage current with a significant enhancement in the current efficiency (CE) from 0.027 cd/A to 4.85 cd/A. These findings reveal that the incorporation of a suitable additive could play a beneficial role in the formation of well-optimized perovskite films which would ultimately lead to the realization of PeLEDs with improved performance.