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

We demonstrate a facile synthetic approach for preparing mixed halide perovskite CH3NH3Pb(Br1-xClx)(3) single crystals by the solvothermal growth of stoichiometric PbBr2 and [(1 - y)CH3NH3Br + yCH(3)NH(3)Cl] DMF precursor solutions. The band gap of CH3NH3Pb(Br1-xClx)(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 CH3NH3Pb(Br1-xClx)(3) single crystals is larger than that of the precursor solution, suggesting an unusual crystal growth mechanism.