Growth and Characterization of PDMS-Stamped Halide Perovskite Single Microcrystals

Recently, halide perovskites have attracted considerable attention for optoelectronic applications, but further progress in this field requires a thorough understanding of the fundamental properties of these materials. Studying perovskites in their single-crystalline form provides a model system for building such an understanding. In this work, a simple solution-processed method combined with PDMS (polydimethylsiloxane) stamping was used to prepare thin single microcrystals of halide perovskites. The method is general for a broad array of materials including CH₃NH₃PbBr₃, CH₃NH₃PbCl₃, CH₃NH₃Pb(Br_0.5Cl_0.5)₃, CH₃NH₃Pb(Br_0.75Cl_0.25)₃, CsPbBr₃, Cs₃Bi₂Br₉, and Cs₃Bi₂I₉. Electron backscatter diffraction (EBSD) was used to investigate the microstructure of the crystals. In order to characterize the microcrystals of CH₃NH₃PbBr₃ electrically, the crystals were grown on prefabricated electrodes creating single-crystal devices contacted from the back. This back-contacted platform circumvents the incompatibility between halide perovskites and the aqueous chemistry used in standard microfabriation processes. It also allows in situ characterization of the perovskite crystal while it operates as a microscopic solar cell.