Exploring the Potential of Cadmium Selenide Nanowires-Based Chalcogenide Devices for Photoelectrochemical Hydrogen Production

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Hydrogen, as a clean fuel and vital industrial chemical, plays a pivotal role in our sustainable energy future, particularly in applications such as the fertilizer and steel industry. To meet the growing demand for renewable hydrogen production, our work focuses on the potential of photoelectrochemical (PEC) water splitting technology. The commercialization of PEC hydrogen production hinges on significant advancements in three key areas: (a) improving solar-to-hydrogen (STH) conversion efficiency, (b) reducing manufacturing costs, and (c) enhancing device durability. Technoeconomic analysis highlights high efficiency as a critical metric, but current triple-junction III-V devices, despite achieving >20% STH, suffer from low durability and high costs. Conversely, single junction oxide materials offer stability and low cost but limited STH performance. Recently, dual-junction tandem PEC devices, configured with a buried photovoltaic-electrocatalyst (PV-EC) architecture, have emerged as promising solutions. This approach integrates semiconducting PV materials beneath an electrocatalyst layer with or without a protective encapsulant, improving overall efficiency and stability. The selection of an appropriate dual-junction PEC device centers on achieving a high voltage (VOC > 1.6 V) with substantial current density (JSC > 10 mA/cm²), minimizing additional power losses due to catalysts and membranes. Within this context, cadmium-based chalcogenides, especially cadmium selenide (CdSe) nanowires and cadmium telluride (CdTe) nanowires, hold promise as top and bottom cell candidates. Although Cd-chalcogenides have made significant strides in the PV industry, their application in PEC hydrogen production remains underdeveloped, particularly concerning their integration with electrocatalysts for stable and efficient solar hydrogen production. This talk will address how we mitigate this gap by developing novel device architectures for fault-tolerant CdSe-based PEC devices, demonstrating their manufacturability at various scales i.e. from lab scale to wafer-scale, and finally, the talk will cover the application of electrodeposited cadmium selenide nanowires and investigating their performance in solar water splitting when interfaced with suitable catalysts within the buried PV-EC architecture.