PNNL

Abstract

Understanding and controlling photo-induced interfacial activity is pertinent to development of efficient light harvesting technologies. Herein, we exploit the exceptional photochromic and redox properties of polyoxometalate anions to develop an integrated photoelectrochemical energy storage cell for conversion and storage of solar energy in a single device. We demonstrate that a complete elimination of coordinating counter cations and preparation of uniform layers of PW12O403- (WPOM) on photoanodes using benchtop ion soft landing (SL) leads to an efficient photo-induced redox conversion of WPOM with an ~80% increase in photocurrent compared to dropcast photoanodes. Raman spectroscopy reveals substantial shifts in the W-Ob-W bridging band of drop casted WPOM compared to soft landed WPOM which is attributed to the detrimental effect of strongly-coordinating counter cations. These findings indicate a new and promising path forward to achieve direct efficient utilization of abundantly available solar energy.