Realization of All-Organic Photoanodes for Photoelectrochemical Cells

Abstract

Organic photoelectrochemical (OPEC) cells are efficient at generating photocurrents but face significant challenges in long-term stability due to the incompatibility of metal oxide charge transport layers with organic photoactive materials and their pH sensitivity. To overcome these issues, we developed an all-organic photoanode incorporating n-type self-assembled monolayers (SAMs) with imide core modifications, which optimize the work function of the ITO substrate, improving charge transfer and the onset potential (V_onset). The addition of a hole-transporting p-type conjugated polyelectrolyte (TPAFS-7TMA) further enhances hole transport and water wettability. This photoanode, designed for ascorbic acid oxidation, achieved a V_onset of 0.25 V_RHE and a photocurrent density (J_ph) of 7.92 mA cm^–2 at oxidation potential and retained 90% of its initial J_ph over 2 h under 1 sun irradiation. This all-organic design effectively addresses the limitations of conventional OPEC cells, providing a stable and efficient alternative for durable OPEC systems. We developed a stable and efficient all-organic photoanode for OPEC cells, utilizing imide-modified n-type SAMs and a p-type conjugated polyelectrolyte to enhance charge transfer, water wettability, and durability, achieving significant performance improvements.