Organic Semiconductor‐BiVO<sub>4</sub> Tandem Devices for Solar‐Driven H<sub>2</sub>O and CO<sub>2</sub> Splitting
Celine Wing See Yeung, Virgil Andrei, Tack Ho Lee, James R. Durrant, Erwin Reisner
Abstract
Abstract Photoelectrochemical (PEC) devices offer a promising platform toward direct solar light harvesting and chemical storage through artificial photosynthesis. However, most prototypes employ wide bandgap semiconductors, moisture‐sensitive inorganic light absorbers, or corrosive electrolytes. Here, the design and assembly of PEC devices based on an organic donor‐acceptor bulk heterojunction (BHJ) using a carbon‐based encapsulant are introduced, which demonstrate long‐term H 2 evolution and CO 2 reduction in benign aqueous media. Accordingly, PCE10:EH‐IDTBR photocathodes display long‐term H 2 production for 300 h in a near‐neutral pH solution, whereas photocathodes with a molecular CO 2 reduction catalyst attain a CO:H 2 selectivity of 5.41±0.53 under 0.1 sun irradiation. Their early onset potential enables the construction of tandem PCE10:EH‐IDTBR – BiVO 4 artificial leaves, which couple unassisted syngas production with O 2 evolution in a reactor completely powered by sunlight, sustaining a 1:1 ratio of CO to H 2 over 96 h of operation.