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- Title
Interplay between Collective and Localized Effects of Point Defects on Photoelectrochemical Performance of TiO<sub>2</sub> Photoanodes for Oxygen Evolution.
- Authors
Yang, Mengya; Cui, Junyi; Daboczi, Matyas; Law, Robert V.; Luke, Joel; Kim, Ji‐Seon; Hankin, Anna; Eslava, Salvador
- Abstract
Among the various photoanode materials investigated for photoelectrochemical water splitting cells, TiO2 stands out due to its abundance, stability, and favorable valence band edge for water oxidation. In this study, the importance of introducing and combining oxygen and titanium vacancy point defects in anatase TiO2 photoanodes to improve their performance is unveiled, achieving a photocurrent density of 0.73 (±0.015) mA cm−2 at +1.23 VRHE under 100 mW cm−2 of simulated sunlight or 26.4 mA cm−2 at +1.23 VRHE under 100 mW cm−2 of 365 nm light. The characterization by X‐ray photoelectron spectroscopy, surface photovoltage, and electron paramagnetic resonance demonstrates that these oxygen and titanium vacancies can have both collective and localized positive effects on the material, leading to a narrowing of the bandgap, an increase in donor density, and an increase in hydroxyl groups on the surface of TiO2. These result in enhanced light absorption, conductivity, and photovoltage, as well as a more negative flat‐band potential and increase in hole flux to the semiconductor–electrolyte interface. These findings provide valuable insights into the role of point defects in modulating the properties of TiO2 and have important implications for the development of high‐performance TiO2‐based devices.
- Subjects
POINT defects; ELECTRON paramagnetic resonance; X-ray photoelectron spectroscopy; SURFACE photovoltage; OXYGEN; PHOTOCATHODES; IONIC conductivity; DYE-sensitized solar cells
- Publication
Advanced Materials Interfaces, 2023, Vol 10, Issue 36, p1
- ISSN
2196-7350
- Publication type
Article
- DOI
10.1002/admi.202300595