(CH3NH3)2PdCl4: A Compound with Two-Dimensional Organic-Inorganic Layered Perovskite Structure

The synthesis of previously unknown perovskite (CH3NH3)(2)PdCl4 is reported. Despite using an organic cation with the smallest possible alkyl group, a 2D organic-inorganic layered Pd-based perovskites was still formed. This demonstrates that Pd-based 2D perovskites can be obtained even if the size of the organic cation is below the size limit predicted by the Goldschmidt tolerance-factor formula. The (CH3NH3)(2)PdCl4 phase has a bulk resistivity of 1.4cm, a direct optical gap of 2.22eV, and an absorption coefficient on the order of 10(4)cm(-1). XRD measurements suggest that the compound is moderately stable in air, an important advantage over several existing organic-inorganic perovskites that are prone to phase degradation problems when exposed to the atmosphere. Given the recent interest in organic-inorganic perovskites, the synthesis of this new Pd-based organic-inorganic perovskite may be helpful in the preparation and understanding of other organic-inorganic perovskites.