Numerical Investigation of Eco‐Friendly All‐Zinc Based Thin Film Solar Cells For Sustainable Photovoltaics

In this numerical study, the performance of thin‐film solar cells comprising entirely Zn‐based layers is evaluated using SCAPS‐1D. ZnSnN₂ is chosen as the absorber layer due to its abundance on earth, and it has good optoelectrical properties suitable for photovoltaic (PV) applications. Its narrow bandgap and high absorption coefficient further enhance its suitability for such devices. The buffer layers explored in this study include ZnN, ZnON, ZnS, and ZnOS, all containing zinc. Likewise, the window layers examined are AZO, GZO, and ZTO. Nickel and Aluminium are used as the front and back contacts. A comprehensive analysis of each layer's properties and potential defects is conducted to improve the solar cell efficiency. The optimized device structure is determined to be Ni/ZnSnN₂/ZnON/ZTO/Al, achieving an efficiency of ≈19% with a short‐circuit current density (Jsc) of 20.05 mA cm−2 and an open‐circuit voltage (Voc) of 1.1 V. These findings present a novel, eco‐friendly, scalable, and efficient thin film solar cell design unlike its predecessor fabricated with toxic and rare earth materials.