[(CH3)2NH2]2PdBr4, a layered hybrid halide perovskite semiconductor with improved optical and electrical properties

Abstract

Inspired by the success of three-dimensional hybrid perovskites (CH₃NH₃)PbX₃ (X = Cl, Br, I), two-dimensional (2D) organic–inorganic hybrid metal halides have drawn immense attention due to their highly tunable physical properties. Moreover, although 3D hybrid perovskite materials have been reported, the development of new organic–inorganic hybrid semiconductors is still an area in urgent need of investigation. Here, we used the dimethylammonium cation to construct a palladium-based halide perovskite material [(CH₃)₂NH₂]₂PdBr₄ with a 2D layered structure. This layered perovskite undergoes one endothermic peak at 415 K corresponding to melting of the organic molecule. The thermal stability of the compound is up to about 500 K. The activation energy and conduction mechanisms are discussed, and the optical study shows a gap energy equal to 2.5 eV. The electrical AC conductivity is in the order of 10⁻⁴ Ω⁻¹ cm⁻¹, which confirms the semiconductor character of this material and indicates its importance in the optoelectronic domain.