Photoinduced Charge-Transfer Dynamics in WO3/BiVO4 Photoanodes Probed through Midinfrared Transient Absorption Spectroscopy

Ivan Grigioni; Mohamed Abdellah; Annamaria Corti; Maria Vittoria Dozzi; Leif Hammarström; Elena Selli

doi:10.1021/jacs.8b08309

Photoinduced Charge-Transfer Dynamics in WO₃/BiVO₄ Photoanodes Probed through Midinfrared Transient Absorption Spectroscopy

J Am Chem Soc. 2018 Oct 31;140(43):14042-14045. doi: 10.1021/jacs.8b08309. Epub 2018 Oct 18.

Authors

Ivan Grigioni¹, Mohamed Abdellah^{2

3}, Annamaria Corti¹, Maria Vittoria Dozzi¹, Leif Hammarström², Elena Selli¹

Affiliations

¹ Dipartimento di Chimica , Università degli Studi di Milano , Via Golgi 19 , 20133 Milano , Italy.
² Department of Chemistry - Ångström Laboratory , Uppsala University , Box 523, 75120 Uppsala , Sweden.
³ Department of Chemistry, Qena Faculty of Science , South Valley University , 83523 Qena , Egypt.

PMID: 30296074
DOI: 10.1021/jacs.8b08309

Abstract

The dynamics of photopromoted electrons in BiVO₄, WO₃, and WO₃/BiVO₄ heterojunction electrodes has been directly probed by transient absorption (TA) midinfrared (mid-IR) spectroscopy in the picosecond to microsecond time range. By comparison of the dynamics recorded with the two individual oxides at 2050 cm^-1 with that of the heterojunction system after excitation at different wavelengths, electron-transfer processes between selectively excited BiVO₄ and WO₃ have been directly tracked for the first time. These results support the charge carrier interactions which were previously hypothesized by probing the BiVO₄ hole dynamics through TA spectroscopy in the visible range. Nanosecond mid-IR TA experiments confirmed that charge carrier separation occurs in WO₃/BiVO₄ electrodes under visible-light excitation, persisting up to the microsecond time scale.