Thermodynamic Analyses of the Two-Step Method of CsPbBr3 Crystal Growth for Inorganic Perovskite Solar Cells

We conducted integrated thermodynamic analyses for the two-step method of CsPbBr 3 growth. Deriving from Gibbs free energy and heterogeneous nucleation theory, a thermodynamic reaction model equation was proposed and verified, from which we could find that the grainsizes of the CsPbBr 3 can be precisely controlled by the CsBr concentration. The impact of temperature of the solvent was also studied. Finally, a best cell was fabricated showing a power conversion efficiency of 4.75%, with open circuit voltage of 1.13 V, short circuit current of 6.68 mA/cm 2 and fill factor of 63%. Our results will help other researchers to determine the appropriate condition of the growth of CsPbBr 3 by the two-step method.