open access

https://hdl.handle.net/2115/80223

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

英語

2020-01-16

American Chemical Society

Journal of physical chemistry Ｃ

124(2)

1292-1302

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 SrTiO3 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 SrTiO3 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).

学術雑誌論文

Accepted Manuscript

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright c American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see https://pubs.acs.org/doi/10.1021/acs.jpcc.9b09324.

1932-7447