Semiconducting polymers as promising materials for photoelectrochemical water splitting

We present high-performance and robust organic photoelectrochemical cells (OPECs) by employing a bulk heterojunction (BHJ) blend of semiconducting polymers as a photoactive layer. Our in-depth study using sacrificial agents for photoreduction and photooxidation unveils critical parameters that significantly affect the performance and operational stability of OPECs: (i) rational selection of semiconducting polymer donor and acceptor to generate free charges efficiently and ensure chemical stability upon illumination, (ii) large surface roughness of interlayers to improve interfacial adhesion, and (iii) mitigation of charge accumulation at the interfaces. By leveraging these insights, our optimized polymer BHJ photocathode and photoanode where the polymer BHJ layers are coupled with hydrogen and oxygen evolution catalysts, respectively, show outstanding performance and unprecedented robustness compared to previous OPECs, demonstrating a new benchmark of OPECs for solar fuel production