Optical Behaviour of Caffeine Mixed Perovskite Photoanode for Photovoltaic Application

Abstract

Halide perovskites such as methylammonium lead triiodide (CH3NH3PbI3) are attracting attention as energy-efficient light absorber materials for photovoltaic applications owing to their solution processing-power, tunable bandgap, strong absorption coefficients and cost-effectiveness. Scanning Electron Microscope (SEM) and Ultra-Violet Visible Spectroscopy (UV-vis) were used to characterize the prepared samples. The substrates were rinsed with propanol to remove impurities and later sintered before precursor deposition with different caffeine ratios via spray pyrolysis. The deposition method was used due to its homogenous ability. The SEM results indicate that the introduction of caffeine enhances nucleation, leading to an increase in the growth rate compared to the control. The UV-vis result shows a redshift to a higher wavelength, indicating an increase in visible light absorption which is attributed to the spectral overlap between the CH3NH3PbI3 absorber and caffeine. The bandgap (Eg) energy analysis further confirmed that the caffeine-modified photoanode is a potential light absorber in perovskite solar cells application. This study provides a good understanding of the optical behaviour of caffeine-mixed perovskite photoanode nanostructures and a promising approach for photon energy management.

Keywords

• caffeine
• perovskite solar cells
• light absorber
• scanning electron microscope
• wavelength