A facile solvothermal growth of single crystal mixed halide perovskite CH3NH3Pb(Br1−xClx)3

Abstract

We demonstrate a facile synthetic approach for preparing mixed halide perovskite (CH₃NH₃)Pb(Br_1−xCl_x)₃ single crystals by the solvothermal growth of stoichiometric PbBr₂ and [(1 − y)CH₃NH₃Br + yCH₃NH₃Cl] DMF precursor solutions. The band gap of (CH₃NH₃)Pb(Br_1−xCl_x)₃ single crystals increased and the unit cell dimensions decreased with an increase in Cl content x, consistent with previous theoretical predictions. Interestingly, the Cl/Br ratio in the (CH₃NH₃)Pb(Br_1−xCl_x)₃ single crystals is larger than that of the precursor solution, suggesting an unusual crystal growth mechanism.