Exploring the potential application of binary 3 <i>d</i> transition metal oxides as electron transport layer in perovskite solar cell devices

Perovskite solar cells (PSCs) are among the most extensively studied photovoltaic technologies due to their excellent performance. A PSC device consists of multiple layers, including a perovskite absorber layer, electron transport layer (ETL), hole transport layer (HTL), and top and bottom conducting layers. The appropriate combination of these layers is crucial for achieving excellent PSCs. In this study, we explore the use of unconventional materials as ETLs for PSCs, specifically binary 3d transition metal oxides (TMOs) such as α-Fe 2 O 3 , ZnO, and Cr 2 O 3 . These materials exhibit excellent optoelectronic and semiconducting properties, making them promising candidates for ETLs in PSCs. We conduct a detailed analysis of the effects of α-Fe 2 O 3 , ZnO, and Cr 2 O 3 as ETLs, focusing on how their structural and electronic properties influence PSC performance. Our investigation includes extensive characterization using X-ray diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared (FTIR) spectroscopy, atomic force microscopy (AFM), ultraviolet-visible (UV-Vis) spectroscopy, and solar simulator. We believe this study will provide valuable insights into the exploration of 3d TMOs as effective ETLs for PSCs. Furthermore, our findings could open new possibilities for utilizing unconventional layer combinations in PSCs, ultimately contributing to the development of high-performance PSCs.