Combinatorial atmospheric pressure chemical vapor deposition of F:TiO2; The relationship between photocatalysis and transparent conducting oxide properties

Andreas Kafizas, Nuruzzaman Noor, Penelope Carmichael, David O. Scanlon, Claire J. Carmalt, Ivan P. Parkin

Research output: Journal article publicationJournal articleAcademic researchpeer-review

32 Citations (Scopus)

Abstract

Combinatorial atmospheric pressure chemical vapor deposition (APCVD) is used to deposit anatase TiO2with a graded level of F-doping between 1.10 ≤ F:Ti (at%) ≤ 2.57 from the reaction of titanium tetrachloride, ethyl acetate and trifluoroacetic acid at 500°C on glass. The photocatalytic activity and electrical resistivity of 200 allotted positions across a grid are screened using high-throughput techniques. A blue region of film is singled out for containing the lowest electrical resistivities of any previously reported doped or undoped TiO2-based system formed by APCVD (ρ ≈ 0.22-0.45 Ω cm, n = 0.8-1.2 × 1018cm-3, μ = 18-33 cm2V-1s-1). The blue region contains a lower fluorine doping level (F:Ti ≈ 1.1-1.6%, Ebg≈ 3.06 eV) than its neighboring colorless region (F:Ti ≈ 2.3-2.6%, Ebg≈ 3.15-3.21 eV, ρ ≈ 0.61-1.3 Ω cm). State-of-the-art hybrid density functional theory calculations were employed to elucidate the nature of the different doping behaviors. Two distinct fluorine doping environments were present. At low concentrations, F substituting for O (FO) dominates, forming blue F:TiO2. At high concentrations, negatively charged fluorine interstitials (Fi-1) begin to dominate, forming transparent F:TiO2. Anatase TiO2with a graded level of F-dopant is grown by combinatorial atmospheric pressure chemical vapor deposition (cAPCVD). The functional properties of 200 positions across the film are rapidly screened. A blue region is singled out for containing the lowest electrical resistivities of any previously reported TiO2-based system grown by APCVD. KGaA, Weinheim.
Original languageEnglish
Pages (from-to)1758-1771
Number of pages14
JournalAdvanced Functional Materials
Volume24
Issue number12
DOIs
Publication statusPublished - 26 Mar 2014
Externally publishedYes

Keywords

  • density functional theory
  • photocatalysis
  • transparent conductive oxides

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Condensed Matter Physics
  • Electrochemistry

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