Chemical conversion of electrodeposited PbO2 to the all-inorganic cesium lead halide perovskites CsPbBr3 and CsPbCl3

There is increasing interest in the development of stable, wide bandgap lead halide perovskites for application as photoelectrodes, light emitting diodes and photosensors. In this work, lead dioxide was electrodeposited from an aqueous electrochemical bath and transformed by a two-step chemical conversion process to CsPbI3, CsPbBr3 and CsPbCl3. X-ray diffraction and scanning electron microscopy measurements confirmed the two-step chemical conversion of PbO2 to PbBr2 or PbCl2 followed by their conversion to the all-inorganic lead halide perovskites CsPbBr3 or CsPbCl3. It was found that chemical conversion of PbO2 to PbI2 and then CsPbI3 led to the non-perovskite δ-CsPbI3. This work presents the first example of the chemical transformation of electrodeposited PbO2 to PbBr2 and PbCl2 to form wide bandgap CsPbBr3 and CsPbCl3 perovskites. Absorbance spectroscopy measurements confirmed the optical gap of the wide bandgap CsPbBr3 and CsPbCl3 materials while linear sweep voltammetry measurements demonstrated that CsPbCl3 has a larger electrochemical stability window than CsPbBr3.