Highly Stable, New, Organic-Inorganic Perovskite (CH3 NH3 )2 PdBr4 : Synthesis, Structure, and Physical Properties.

Abstract

Lead halide perovskites have attracted striking attention recently, due to their appealing properties. However, toxicity and stability are two main factors restricting their application. In this work, a less toxic and highly stable Pd-based hybrid perovskite was experimentally synthesized, after exploring different experimental conditions. This new hybrid organic-inorganic perovskite (CH3 NH3 )2 PdBr4 was found to be an orthorhombic crystal (Cmce, Z=4) with lattice parameters a=8.00, b=7.99, c=18.89 Å. The Cmce symmetry and lattice parameters were confirmed using Pawley refinement and the atoms positions were confirmed based on DFT calculation. This perovskite compound was determined to be a p-type semiconductor, with a resistivity of 102.9 kΩ cm, a carrier concentration of 3.4 ×1012 cm-3 , and a mobility of 23.4 cm2 (V s)-1 . Interestingly, XRD and UV/Vis measurements indicated that the phase of this new perovskite was maintained with an optical gap of 1.91 eV after leaving in air with a high humidity of 60 % for 4 days, and unchanged for months in N2 atmosphere; much more stable than most existing organic-inorganic perovskites. The synthesis and various characterizations of this work further the understanding of this (CH3 NH3 )2 PdBr4 organic-inorganic hybrid perovskite material.