Highly‐Active Chiral Organic Photovoltaic Catalysts with Suppressed Charge Recombination

Abstract

Recombination of free charges in organic semiconductors reduces the available photo‐induced charge‐carriers and restricts photovoltaic efficiency. In this work, the chiral organic semiconductors (Y6‐R and Y6‐S with enantiopure R‐ and S‐ chiral alkyl sidechains) are designed and synthesized, which show effective aggregation‐induced chirality through mainchain packing with chiral conformations in non‐centrosymmetric space groups with tilt chirality. Based on the analysis of spin‐injection, magnetic‐hysteresis loop, and thermodynamics and dynamics of the excited state, we suggest that the aggregation‐induced chirality can generate spin‐polarization, which suppresses charge recombination and offers more available charge‐carriers within Y6‐R and Y6‐S relative to the achiral counterpart (Y6). Then the chiral Y6‐R and Y6‐S show enhanced catalytic activity with optimal average hydrogen evolution rates of 205 and 217 mmol h−1 g−1, respectively, 60–70 % higher than Y6, when they are employed as nanoparticle photocatalysts in photocatalytic hydrogen evolution under simulated solar light, AM1.5G, 100 mW cm−2.