Target‐Induced Dye‐Sensitized Solar Cell Design on Photoelectrochemical Anode for Improved Enantiomer Discrimination

Abstract The generation, separation, and interfacial redox reactions of photoinduced carriers are key issues in photoelectrochemical (PEC) techniques. To overcome the limitations of most metal‐oxide semiconductors (MOSs), including their inherent wide bandgap and inefficient photon utilization in PEC‐based sensing applications, an effective strategy is developed that introduces the dye‐sensitized solar cells (DSSC) design into PEC techniques (DSSC‐PEC) for target determination. As a proof of principle for such a DSSC‐PEC method, 3,4‐dihydroxyphenylalanine (DOPA) enantiomers are investigated as the identification targets. Utilizing the L‐/D‐DOPA recognition on a chiral TiO 2 photoelectrode, Pt nanoclusters (Pt NC ) are then introduced via the catechol coordination with DOPA. These Pt NC act as cocatalysts for the TiO 2 photoelectrode and are further integrated with ruthenium‐based N719 dye antennas to establish a DSSC design on the photoelectrode. With the aid of iodide/triiodide (I − /I 3 − ) redox couple in a non‐aqueous electrolyte, the oxidized N719 can be rapidly regenerated, ensuring stable and robust photocurrent generation. Since the cocatalyst loading amount is directly correlated with the L‐ and D‐DOPA recognized on the chiral photoelectrode, enantioselective and sensitive discrimination can thus be achieved based on the changes in photocurrent. Such a target‐recognition‐induced DSSC‐PEC strategy provides new insights into the design of MOSs‐based PEC sensing devices.