Luminescent Solar Concentrators for Photoelectrochemical Water Splitting

Solar-driven electrolysis accomplished through photovoltaic (PV) devices is a major candidate for a long-term sustainable energy economy. However, the visually appealing integration of PV cells or panels into the built environment or in mobile applications is a fundamental requirement for this technology to expand and grow further. In this view, we investigated the exploitation of a luminescent solar concentrator (LSC) comprising multiple c-Si cells connected in series and parallel as a semitransparent device, capable of carrying out water electrolysis without an external bias. The optimized monolithic device comprises two series of four PV cells connected in parallel integrated into a planar LSC of 19.36 cm2 area, externally wired to an electrochemical cell having Pt and Ru-based electrodes as cathode and anode, respectively. LSC devices are evaluated under different illumination conditions, including diffuse light, to simulate urban or indoor environments. Maximum solar-to-hydrogen efficiency (STH) of 1.55% at 1 sun AM 1.5 G can be obtained with this setup, considering the whole front LSC area. These results represent the first demonstration of an electrolysis-based energy storage system exploiting LSC technology.