Investigation of the a-plane Oriented Zinc Oxide (ZnO) as an Active Photo-Layer, a Promising Inorganic Material for Solar Cell Applications Based on Bulk Heterojunctions (BHJs)

This study presents the characterization of thin film-oriented A-plane ZnO. The experimental investigation involves photoluminescence (PL) and reflectivity spectroscopy to analyze the material’s optical properties. The perpendicular polarisation (E⊥c) of the experimental reflectivity spectra at low temperature of the a-plane oriented ZnO grown on r-plane (0112) sapphire substrates by plasma-assisted molecular beam epitaxy, shows two types of excitons, Exciton A and B. This finding suggests strong light-matter interaction and promising optoelectronic properties for the a-plane-oriented ZnO thin film in photovoltaic applications. The reflectivity spectra further support the observation by providing insights into the material’s energy band structure and optical transitions. Quantum Espresso has been used for the investigation of the Band Structure of the a-plane ZnO. Overall, this work establishes the potential of a-plane-oriented ZnO thin films as a viable candidate for enhancing the efficiency of photovoltaic cells through tailored light absorption and emission properties. Further investigations are warranted to optimize the thin film’s growth conditions and integration into solar cell architectures.