Dynamic disorder in ABX 3 (A=3D CH 3 NH 3 , Cs; B=3D Pb; X=3D Br 3 , CI 3 ) perovskites

Lead-halide hybrid perovskite crystals have emerged as potentially materials for solar cells due to their power conversion efficiency over 20% [1]. In this work we conduct a comparative study between two hybrids (CH 3 NH 3 PbBr 3 and CH 3 NH 3 Pba 3 ) and an all-inorganic lead-halide perovskite (CsPbBr 3 ). Both have the general ABX 3 perovskite formula, with similar band gap (2.2 eV) and similar structural phase sequence, orthorhombic at low temperature, changing to tetragonal and then to cubic as temperature is increased [2]. Theoretical studies suggested that dynamic disorder, imposed by the rotation of anisotropic organic molecules in the inorganic octahedral network, plays an important role in the high photovoltaic activity presented by this perovskites [3,4].