Time-Resolved Raman Spectroscopy of Polaron Formation in a Polymer Photocatalyst
Verity L. Piercy, Khezar H. Saeed, Andrew W. Prentice, Gaia Neri, Chao Li, Adrian M. Gardner, Yang Bai, Reiner Sebastian Sprick, Igor V. Sazanovich, Andrew I. Cooper, Matthew J. Rosseinsky, Martijn A. Zwijnenburg, Alexander J. Cowan
Abstract
Polymer photocatalysts are a synthetically diverse class of materials that can be used for the production of solar fuels such as H2, 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 (TR3) spectroscopy to study the formation of polaron pairs and electron polarons in one of the most active linear polymer photocatalysts for H2 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.