In-situ plasma hydrogenated TiO{sub 2} thin films for enhanced photoelectrochemical properties

Journal Article · Fri Apr 15 04:00:00 EDT 2016 · Materials Research Bulletin

DOI:https://doi.org/10.1016/J.MATERRESBULL.2015.12.015· OSTI ID:22581506

Singh, Aadesh P.; Kodan, Nisha ^[1]; Dey, Avishek; Krishnamurthy, Satheesh ^[2]

---

1. Thin Film Laboratory, Department of Physics, Indian Institute of Technology, Hauz Khas, New Delhi 110016 (India)
2. Materials Engineering, The Open University, Milton Keynes, MK7 6AA (United Kingdom)

Highlights: • Growth of TiO{sub 2} thin films with in-situ plasma hydrogenation. • Presence of Ti{sup 2+} states in addition to Ti{sup 3+} states present in pristine TiO{sub 2}. • Change in VBM, work function and band gap in iH:TiO{sub 2}. • Enhanced photocurrent density as compared to pristine TiO{sub 2} films. - Abstract: In this paper, we report the effect of in-situ plasma hydrogenation of TiO{sub 2} (iH:TiO{sub 2}) thin films by the incorporation of known amount of hydrogen in the Ar plasma during rf-sputter deposition of TiO{sub 2} films. As compared to pristine TiO{sub 2} films (∼0.43 mA/cm2 at 0.23 V vs Ag/AgCl), hydrogenated TiO{sub 2} showed enhanced photoelectrochemical activity in terms of improved photocurrent density of ∼1.08 mA/cm2 (at 0.23 V vs Ag/AgCl). These results are explained in terms of reduction in band gap energy, shift in valence band maximum away from the Fermi level, improved donor density and more negative flat band potential in iH:TiO{sub 2} sample. The presence of Ti{sup 2+} states in iH:TiO{sub 2} films in addition to Ti{sup 3+} states in pristine TiO{sub 2} act as additional electronic states in the TiO{sub 2} band gap and increases the optical absorption in the visible region. This method of in-situ hydrogenation can be used as a general method for improving the properties of metal oxide thin films for photoelectrochemical and photocatalytic applications.

• OSTI ID: 22581506
• Journal Information: Materials Research Bulletin, Journal Name: Materials Research Bulletin Vol. 76; ISSN MRBUAC; ISSN 0025-5408
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
COMPARATIVE EVALUATIONS
DEPOSITION
ENERGY GAP
FERMI LEVEL
HYDROGEN
HYDROGENATION
OPTICAL PROPERTIES
PHOTOCATALYSIS
PHOTOCURRENTS
PLASMA
SILVER CHLORIDES
THIN FILMS
TITANIUM IONS
TITANIUM OXIDES
VALENCE
WORK FUNCTIONS