Crystallization Behavior and Luminescence of Inkjet Printing CH3NH3PbBr3

Lead halide perovskites display remarkable optoelectronic properties, like large absorption coefficients, high photoluminescence quantum efficiencies, and long lifetime and diffusion length of photocarriers. This system is easily fabricated using solution processes and inkjet printing is an effective way to prepare halide perovskite films and complex patterns. In this work, the crystallization behaviors of inkjet printing CH3NH3PbBr3 crystals are systematically investigated with varied I− doping, printing times, and solvents. Using N,N‐dimethylformamide (DMF) solvent, CH3NH3PbBr3−xIx (x = 0, 0.14, 0.29, 0.45, 0.59) are printed on the glass and the crystalline grains are developed from the (001) oriented tetragonal in side length of 10–50 µm to dendrite with increasing I− concentrations. The crystalline grains are kept tetragonal, while the average crystal size changes from 22 to 89 µm by increasing the number of printing from 10 to 1000 times. DMF and dimethyl sulfoxide (DMSO) are used as solvents for printing CH3NH3PbBr3, and more regular grains are obtained from DMF solvent. Several patterns are printed on glass and papers, and fluorescent two‐dimensional (2D) patterns are observed under the 480 nm excitation. The as‐printed patterns show excellent homogeneity and high reproducibility, indicating that the inkjet printing shows broad application prospects in flexible electronics.