POS6-0702
Molecular Interface Engineering of Organic Photoanodes for Efficient Photoelectrochemical Water Splitting
Topic
S6. Emerging Polymer and Hybrid Materials for Advanced Energy Storage and Conversion
When and Where
Sep 29, 2026
08:30 - 09:30
Room 301 (Grand Ballroom)
Session Chairs
Hae Jung SON
Boseok KANG
Presenter(s)
Wonjun Kim (UNIST)
Co-Author(s)
Abstract
Solar-driven photoelectrochemical water splitting is an attractive approach for converting renewable solar energy into storable chemical fuels. Organic photoelectrodes are particularly promising because of their high photovoltage, tunable electronic and optical properties, light-weight, and compatibility with solution-based fabrication. However, charge losses at internal interfaces still limit efficient carrier extraction and overall photoelectrochemical performance. Here, we present a molecular interface engineering strategy for organic photoanodes by modifying the ZnO electron-transport layer/photoactive-layer interface with an n-type conjugated phosphonic acid molecular interlayer. The molecular interlayer chemisorbs onto ZnO, passivates defect-related surface states, and regulates the interfacial electronic environment, leading to more favorable charge transport and reduced interfacial recombination. The resulting devices exhibit improved charge extraction and lower parasitic leakage losses. When integrated with a NiFe-layered double hydroxide catalyst for the oxygen evolution reaction, the modified organic photoanode shows a cathodically shifted onset potential from 0.61 to 0.56 V vs. RHE and an increased photocurrent density from 23.58 to 24.81 mA cm-2 at 1.23 V vs. RHE. The device further achieves a half–solar-to-hydrogen efficiency of 7.89% together with enhanced operational stability under alkaline conditions. These results demonstrate that molecular control of internal interfaces provides an effective route to improve charge extraction, photoelectrochemical performance, and durability in organic photoanodes, offering a promising strategy for efficient solar-to-chemical energy conversion.
