Polymer photocatalysts, Nanoparticles, Hydrogen evolution, Förster resonance energy transfer, Renewable energy sources, TJ807-830, Ecology, QH540-549.5

Organic nanophotocatalysts are promising candidates for solar fuels production, but they still face the challenge of unfavorable geminate recombination due to the limited exciton diffusion lengths. Here, we introduce a binary nanophotocatalyst fabricated by blending two polymers, PS-PEG5 (PS) and PBT-PEG5 (PBT), with matched absorption and emission spectra, enabling a Förster resonance energy transfer (FRET) process for enhanced photocatalysis. These heterostructure nanophotocatalysts are processed using a facile and scalable flash nanoprecipitation (FNP) technique with precious kinetic control over binary nanoparticle formation. The resulting nanoparticles exhibit an exceptional photocatalytic hydrogen evolution rate up to 65 mmol g−1 h−1, 2.5 times higher than that single component nanoparticles. Characterizations through fluorescence spectra and transient absorption spectra confirm the hetero-energy transfer within the binary nanoparticles, which prolongs the excited-state lifetime and extends the namely “effective exciton diffusion length”. Our finding opens new avenues for designing efficient organic photocatalysts by improving exciton migration.