Interface engineering in p-NiO/n-SnO2 thin film heterojunction for solar cell applications

Metal oxides belong to a unique class of materials which exhibit appreciable level of electrical conductivity and high optical transparency in visible region, rendering them highly suitable for a wide range of optoelectronic and photovoltaic applications. The aim of this study is to investigate the phenomena of electrical conduction and charge transfer dynamics in p-NiO/n-SnO 2 thin-film heterojunction through band alignment engineering. Thin films were comprehensively characterized by XRD, SEM, AFM, EDX, PL, UV–Vis-NIR spectroscopy, and Hall-Effect measurements to evaluate their structural, morphological, compositional, optical, and electronic properties. The proposed heterojunction with device geometry of Al/NiO/SnO 2 /ITO demonstrated a turn-on voltage of ∼1.27 V with an ideality factor of ∼1.97. The process of carrier diffusion, recombination and extraction of charges is systematically examined with the help of band diagram. Under A.M 1.5 G illumination, the p-n heterojunction device exhibits an open-circuit voltage of ∼0.48 V, short-circuit current density of ∼3.8 mA cm −2 , fill factor of ∼0.28, and power-conversion efficiency of ∼0.13%. Thus, the development of all-oxide p-n heterojunction thin film solar cell represents a promising and sustainable approach to meet the growing global demand for clean energy.