Ionic liquid-assisted growth of high-quality methylammonium lead bromide single crystals for photodetection applications

Abstract

The control of nucleation temperature and growth kinetics during inverse temperature crystallization (ITC) is critical for achieving high-quality perovskite single crystals (SCs) for various optoelectronic applications. Here, we show that the addition of a 1-butyl-3-methylimidazolium bromide (BMIB) ionic liquid to the methylammonium lead bromide (MAPbBr₃) precursor solution not only reduces the nucleation temperature from 80 °C to 60 °C but also substantially improves the crystal quality and optoelectronic properties. Specifically, MAPbBr₃ SCs grown in the presence of BMIB exhibit better crystallinity with reduced lattice strain, nonradiative recombination and trap density compared to the MAPbBr₃ SCs grown by the conventional ITC method at 80 °C. The high quality of the BMIB-based MAPbBr₃ SCs enabled us to build an efficient planar-structured photodetector with high responsivity to green light (530 nm). This study shows that the ionic liquid-assisted growth of perovskite SCs has a significant influence on the crystal properties, which is beneficial for optoelectronic SC-based devices.