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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Contrasting transient photocurrent characteristics for thin films of vacuum-doped ``grey{''} TiO2 and ``grey{''} Nb2O5

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de Araujo, Moises A. [1, 2] ; Gromboni, Murilo F. [2] ; Marken, Frank [1] ; Parker, Stephen C. [1] ; Peter, Laurence M. [1] ; Turner, Josh [3] ; Aspinall, Helen C. [3] ; Black, Kate [3] ; Mascaro, Lucia H. [2]
Total Authors: 9
[1] Univ Bath, Dept Chem, Claverton Down, Bath BA2 7AY, Avon - England
[2] Univ Fed Sao Carlos, Dept Chem, Rod Washigton Luiz, Km235, BR-13565905 Sao Carlos, SP - Brazil
[3] Univ Liverpool, Sch Engn, Liverpool L69 3GH, Merseyside - England
Total Affiliations: 3
Document type: Journal article
Source: APPLIED CATALYSIS B-ENVIRONMENTAL; v. 237, p. 339-352, DEC 5 2018.
Web of Science Citations: 1

Photo-catalytic performance for oxide films, here for inkjet-printed TiO2 (ca. 1 mu m thickness on PTO) and for spray-pyrolysis-coated Nb2O5 (ca. 1 mu m thickness on PTO), is affected by oxygen vacancies that form during vacuum-heat treatment at 550 degrees C. The effects of the oxygen vacancies are associated with formation of Ti(III) and Nb(IV) sites, respectively, and therefore optically visible as ``grey{''} coloration. Photo-electrochemical light-on-off transient experiments are performed in the limit of thin film photoanodes, where front and back illumination result in the same photo-current responses (Le. with negligible effects from internal light absorption gradients). It is shown that generally the magnitude of photo-currents correlates linearly with light intensity, which is indicative of dominant ``photo-capacitive{''} behaviour. At an applied voltage of 0.4 V vs. SCE (in the plateau region of the photo-current responses) the potential and also the pH (going from 1.0 M KOH to 0.1 M HClO4 in the presence of methanol quencher) have no significant effect on photo-currents; that is, surface chemical/kinetic effects appear to be unimportant and interfacial hole transfer may be rate limiting. Under these conditions (and based on a simplistic mechanistic model) changes in photo-currents introduced by oxygen vacancy doping (detrimental for TiO2 and beneficial for Nb2O5) are assigned primarily to changes in electron mobility. (AU)

FAPESP's process: 16/12681-0 - Preparation and characterization of ternary sulfide semiconductor thin films of antimony and tin, TAS (t = tin, antimony and a = s = sulfur), for use in photovoltaic cells
Grantee:Moisés Albuquerque de Araújo
Support type: Scholarships in Brazil - Doctorate
FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
Grantee:Elson Longo da Silva
Support type: Research Grants - Research, Innovation and Dissemination Centers - RIDC
FAPESP's process: 14/50249-8 - Green chemistry: sustainable synthetic methods employing benign solvents, safer reagents, and bio-renewable feedstock
Grantee:Arlene Gonçalves Corrêa
Support type: Research Grants - Research Centers in Engineering Program