For the first of time, we demonstrate that methylammonium cadmium halides show photoelectrochemical (PEC) response with excellent humidity and chemical resistance because the oxidation state of almost all cadmium compounds is +2. The photocurrent densities of two-dimensional (2D) layered (MA)2CdCl4 perovskites are about 0.30 mA cm-2 under 100 mW cm-2 irradiation. The interaction between these methylammonium cadmium halides and water vapor is studied by probing film morphology and characterizing single crystal structure. It is shown that H2O is able to complex with the perovskite, forming a hydrate product with the molecular formula of MACd3Cl7·3H2O upon humidity exposure. This causes a decrease in absorption and a recognizable change in the crystal structure of the material. When compared to methyl-ammonium lead iodide (MAPbI3), the PEC stability of 2D layered (MA)2CdCl4 perovskites with BQ/BQ- redox couples (where BQ is benzoquinone) in CH2Cl2 is enhanced from 50 hours to 600 hours, exhibiting an increase of 12 times.
ASJC Scopus subject areas
- Materials Chemistry