CH₃NH₃PbI₃ and CH₃NH₃PbBr₃ films deposited by automated spray-pyrolysis for applications in photovoltaic energy

Abstract

This work aimed to produce CH₃NH₃PbI₃ and CH₃NH₃PbBr₃ films on glass substrates via the automated spray-pyrolysis technique for application as an absorber layer of photovoltaic cells. Their properties were investigated and compared by varying deposition parameters, such as the temperature (250, 300, 350, and 400 °C) and the precursor solution flow (0.25, 0.50, and 0.75 mL/min). Structural characterization by X-ray diffraction revealed the formation of orthorhombic perovskite films. The most adequate temperature and solution flow were 300 °C and 0.50 mL/min for both bromine and iodide films. Morphologically, the films were uniform and free from cracks. CH₃NH₃PbI₃ and CH₃NH₃PbBr₃ films respectively had an optical gap of 1.5 and 2.3 eV, a thickness of 4.56 and 2.35 µm, an absorption coefficient of 0.58x10⁴ and 0.50x10⁴ cm^-1, a resistivity of 21.80 and 24.20 kΩ.m, and a figure of merit of 2.66 and 2.07. It was concluded that, between the two compounds, the CH₃NH₃PbI₃ layer has better performance for photovoltaic applications.

Keywords:
solar cell; perovskite; spray-pyrolysis