Time-Resolved Raman Spectroscopy of Polaron Formation in a Polymer Photocatalyst

[Image: see text] Polymer photocatalysts are a synthetically diverse class of materials that can be used for the production of solar fuels such as H(2), but the underlying mechanisms by which they operate are poorly understood. Time-resolved vibrational spectroscopy provides a powerful structure-specific probe of photogenerated species. Here we report the use of time-resolved resonance Raman (TR(3)) spectroscopy to study the formation of polaron pairs and electron polarons in one of the most active linear polymer photocatalysts for H(2) production, poly(dibenzo[b,d]thiophene sulfone), P10. We identify that polaron-pair formation prior to thermalization of the initially generated excited states is an important pathway for the generation of long-lived photoelectrons.