Photogenerated Charge Carriers Dynamics on La- and/or Cr-Doped SrTiO3 Nanoparticles Studied by Transient Absorption Spectroscopy

authored by

Fumihiko Ichihara, Fabian Sieland, Hong Pang, Davin Philo, Anh Thu Duong, Kun Chang, Tetsuya Kako, Detlef W. Bahnemann, Jinhua Ye

Abstract

Elemental doping into semiconductor-based photocatalysts to narrow the bandgap, thus extending the light absorption to visible light region, is a conventional and widely adopted strategy for water splitting (or artificial photosynthesis) application. However, one critical problem but rarely addressed, is the drastically decreased photocatalytic activity under UV light despite of the increased activity in visible light region, resulting in a decreased total performance under full solar spectrum. In order to elucidate the origin of the commonly observed phenomena, herein we choose La,Cr-codoped SrTiO

₃ as a proof-of-concept model to probe the effect of dopants on the behavior of photogenerated charge carriers by transient absorption spectroscopy. By observing the excitons, it is found that under UV irradiation, the excitation occurring from the Cr impurity bands limits the excitation of SrTiO

₃ from valence band, causing the drastic decrease of the photocatalytic activity over doped material. The widely proposed recombination at dopant sites, however, is not dominant for declining the UV light-irradiated performance, especially in the presence of reactant gas (methanol vapor).

Organisation(s)

Institute of Technical Chemistry

External Organisation(s)

Hokkaido University
Nanjing University of Aeronautics and Astronautics
Saint Petersburg State University
Tianjin University
National Institute for Materials Science Tsukuba

Type

Article

Journal

Journal of Physical Chemistry C

Volume

124

Pages

1292-1302

No. of pages

ISSN

1932-7447

Publication date

16.01.2020

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

Electronic, Optical and Magnetic Materials, General Energy, Physical and Theoretical Chemistry, Surfaces, Coatings and Films

Sustainable Development Goals

SDG 7 - Affordable and Clean Energy

Electronic version(s)

https://eprints.lib.hokudai.ac.jp/dspace/handle/2115/80223 (Access: Open)
https://doi.org/10.1021/acs.jpcc.9b09324 (Access: Closed)