An Organic Semiconductor Photoelectrochemical Tandem Cell for Solar Water Splitting

Photoelectrochemical cells employing organic semiconductors (OS) are promising for solar-to-fuel conversion via water splitting. However, despite encouraging advances with the half reactions, complete overall splitting remains a challenge. Herein, robust photocathode operating in near-neutral pH electrolyte by careful selections of semiconducting polymer bulk heterojunction (BHJ) blend and charge-selective layer is realized. The optimized produces photocurrent density >4 mA cm?2 at 0 V vs reversible hydrogen electrode (VRHE) solar reduction noticeable operational stability (retaining ?90% initial performance over 6 h) 9. Combining BHJ benchmark photoanode leads to demonstration large-area (2.4 cm2) photoelectrochemical tandem cell splitting, predicted solar-to-hydrogen (STH) efficiency 0.8%. Under unassisted two-electrode operation (1 Sun illumination) stabilized 0.6 an STH 0.3% observed together near unity Faradaic H2 O2 production.