Self-assembly of size-controlled perovskite crystallite arrays on modulated substrates for laser applications†

Abstract

In recent years, organo–inorganic hybrid lead halide perovskite semiconductors have made significant progress in fields such as solar cells, light-emitting diodes, detectors, and lasers owing to their excellent photoelectric properties. Perovskite crystallites can be used to achieve micro-nanoscale lasers, which would provide a light source for integrated photonics. Previous studies have reported that it is difficult to prepare perovskite crystals using one-step solution processing to achieve orderly distribution on the substrate and optical resonators with high-quality factors because of random nucleation and excessive nucleation points. Orderly distribution is mostly achieved through more complicated inkjet printing. In this work, a poly(4-butylphenyl-diphenyl-amine) (poly-TPD) layer was spun on a substrate to reduce the wettability of a perovskite precursor solution, which leads to a decrease in the number of nucleation points during the growth of perovskite crystals, obtaining a perovskite crystallite array with good laser properties. The distribution and laser threshold of perovskite crystallites on different material substrates around poly-TPD material systems are discussed. By utilizing special large-sized crystallites, continuous variation in the grain size of perovskite crystallites is achieved, thereby enabling the investigation on the impact of grain size on the laser threshold.