Stability of self-assembled organic-inorganic layered perovskite

Photo-stability of (C6H5C2H4NH3)(2)PbX4 (X; Br and I) films was studied and the degradation processes were discussed. The prepared films were not stable against the UV-light irradiation. The PhE-PbX4 films were readily oxidized by the UV-light irradiation in air. In vacuum, the PhE-PbI4 films changed to beta-phenethylamine intercalated PbI2 due to the elimination of halogen species. On the contrary, no degradation was observed for the PhE-PbBr4 films. These results suggested that the photo-irradiation induced photochemical reaction was one of the possible reasons for the degradation. To suppress the oxidation and halogen elimination induced by the photochemical reaction, PMMA-coated PhE-PbX4 films were also fabricated and their photo-stability was examined.