Operando IR Optical Control of Localized Charge Carriers in BiVO4 Photoanodes.
J Am Chem Soc
; 145(32): 17700-17709, 2023 Aug 16.
Article
in En
| MEDLINE
| ID: mdl-37527512
ABSTRACT
In photoelectrochemical cells (PECs) the photon-to-current conversion efficiency is often governed by carrier transport. Most metal oxides used in PECs exhibit thermally activated transport due to charge localization via the formation of polarons or the interaction with defects. This impacts catalysis by restricting the charge accumulation and extraction. To overcome this transport bottleneck nanostructuring, selective doping and photothermal treatments have been employed. Here we demonstrate an alternative approach capable of directly activating localized carriers in bismuth vanadate (BiVO4). We show that IR photons can optically excite localized charges, modulate their kinetics, and enhance the PEC current. Moreover, we track carriers bound to oxygen vacancies and expose their â¼10 ns charge localization, followed by â¼60 µs transport-assisted trapping. Critically, we demonstrate that localization is strongly dependent on the electric field within the device. While optical modulation has still a limited impact on overall PEC performance, we argue it offers a path to control devices on demand and uncover defect-related photophysics.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Language:
En
Journal:
J Am Chem Soc
Year:
2023
Document type:
Article
Affiliation country:
United kingdom