Metal tungstate as an electron transport layer: Diverse preparation methods and photovoltaic applications

Nanomaterials derived from metal tungstates featuring transition metals have emerged as a focal point in electrochemical research due to their abundant natural sources, cost-effectiveness, and environmentally friendly characteristics. This review examines the potential of metal tungstate (MWOx) as an electron transport material (ETM) to enhance the performance of photovoltaic (PV) devices, proposing it as an alternative to traditional TiO2-based ETMs. The first section explores various preparation methods, including wet chemical processes, solid-state synthesis, and bombardment techniques. The second section critically investigates recent advancements in utilizing MWOx for high-performance PV devices, revealing its significant potential to replace conventional ETMs. The application of ultra-thin transition metal oxides (TMOs) in dye-sensitized, organic PV, and perovskite (PSK)-based solar cells is discussed in detail. We also highlight the rapidly expanding research interest in this topic over the past several years. Finally, we provide a perspective on the challenges and future directions in this field.