Bismuth Doping Alters Structural Phase Transitions in Methylammonium Lead Tribromide Single Crystals

We study the effects of bismuth doping on crystal structure and phase transitions in single crystals perovskite semiconductor methylammonium lead tribromide, MAPbBr3. By measuring temperature-dependent specific heat capacity (Cp) we find that, as Bi increases, transition assigned to cubic tetragonal boundary decreases temperature. Furthermore, after observe one between 135 155 K, contrast two observed undoped crystal. These results appear strikingly similar previously reported mechanical pressure structure. Using X-ray diffraction, show that lattice constant is incorporated into crystal, predicted by density functional theory (DFT). propose substitutional site dominant, resulting BiPb+ centers which induce compressive chemical strain alters crystalline transitions.