The Polymer Society of Korea

Abstract

Efficient and stable photoelectrochemical (PEC) systems are vital for solar-to-hydrogen conversion. Organic semiconductors are promising for OPEC devices due to broad absorption and tunable energy levels. However, bulk heterojunction (BHJ) structures suffer from non-selective charge transport, causing severe interfacial recombination and reactive oxygen species formation at surface-exposed acceptors, compromising stability. We report all polymer pseudo-bilayer (PS-Bi) photoanodes via sequential deposition to effectively address these issues. This vertically ordered morphology ensures selective hole positioning at the electrode surface, suppressing recombination. As a result, PS-Bi photoanodes exhibit negatively shifted onset potentials and enhanced stability over their BHJ counterparts. EIS reveals that improved charge transport in PS-Bi minimizes interfacial charge accumulation. This study establishes PS-Bi structures as a robust strategy for high-performance and stable OPEC systems.