Thin Film Chalcogenides from Solar Cells to Solar Fuels

Thin film absorber layers based on chalcogenides such as CdTe, CIGS, and more recently Sb₂(Se,S)₃, are established staples of solar cell research. These materials have good power conversion efficiencies from a range of vapour transport deposition processes and in the case of CdTe have even made the leap from the laboratory to mass scale module production. The same factors that make these materials attractive for photovoltaics, low-cost materials, rapid deposition techniques and high optical absorption, make them equally suited for solar driven photoelectrochemical (PEC) water splitting for the production of hydrogen. This talk will focus on how chalcogenide thin films deposited via an industrially scalable close space sublimation (CSS) process, can be utilised effectively as PV absorbers and then transferred to use as photocathode materials in PEC devices. We will discuss the challenges of modifying the device architecture between PEC and PV technologies, as well as routes to grain structure control in polycrystalline CdTe and Sb₂Se₃ and how it ultimately determines device performance.