Optical and electrochemical characterizations are carried out in conjunction with first-principles calculations on pure and N-doped titania nanocrystals. These are prepared in laboratory with initial doping concentrations of triethylamine in the range of 0.1-0.5 N/Ti molar ratio. Diffuse reflectance UV-vis spectra of N-doped samples present a significant absorption in the visible region. The flatband potential (Efb) of pure and nitrogen-doped TiO2 (-0.6 ± 0.2 V vs NHE) is determined by impedance spectroscopy (Mott-Schottky plots) and the quasi-Fermi level, nEF* (-0.67̄V vs NHE) by photovoltage measurements as a function of the suspension pH in the presence of an electrochemical probe (methylviologen, MV2+). Theoretical density of electronic states calculations, where several N doping versus vacancy combinations are taken into consideration, together with the optical and electrochemical experiments allow us to draw a detailed picture of the electronic features of the doped samples.
Electronic structure of Pure and N-doped TiO2 Nanocrystals by Electrochemical Experiments and First Principles Calculations / F. Spadavecchia, G. Cappelletti, S. Ardizzone, M. Ceotto, L. Falciola. - In: JOURNAL OF PHYSICAL CHEMISTRY. C. - ISSN 1932-7447. - 115:14(2011 Mar 10), pp. 6381-6391. [10.1021/jp2003968]
Electronic structure of Pure and N-doped TiO2 Nanocrystals by Electrochemical Experiments and First Principles Calculations
F. Spadavecchia;G. Cappelletti;S. Ardizzone;M. Ceotto;L. Falciola
2011
Abstract
Optical and electrochemical characterizations are carried out in conjunction with first-principles calculations on pure and N-doped titania nanocrystals. These are prepared in laboratory with initial doping concentrations of triethylamine in the range of 0.1-0.5 N/Ti molar ratio. Diffuse reflectance UV-vis spectra of N-doped samples present a significant absorption in the visible region. The flatband potential (Efb) of pure and nitrogen-doped TiO2 (-0.6 ± 0.2 V vs NHE) is determined by impedance spectroscopy (Mott-Schottky plots) and the quasi-Fermi level, nEF* (-0.67̄V vs NHE) by photovoltage measurements as a function of the suspension pH in the presence of an electrochemical probe (methylviologen, MV2+). Theoretical density of electronic states calculations, where several N doping versus vacancy combinations are taken into consideration, together with the optical and electrochemical experiments allow us to draw a detailed picture of the electronic features of the doped samples.File | Dimensione | Formato | |
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