An experimental and theoretical study on the electronic and structural properties of CdSe@TiO2 nanotube arrays

Autor(es)

Freitas, R. G. ; Lucas, F. W. S. ; Santanna, M. A. ; Mendes, R. A. ; Terezo, A. J. ; de Souza, G. L. C. ; Mascaro, L. H. ; Pereira, E. C.

• Tipo de documento: Artigo Científico
• Fonte: Physical Chemistry Chemical Physics; v. 18, n. 38, p. 26885-26893, OCT 14 2016.
• Citações Web of Science: 5

Resumo

In this work, the effects of the structural (crystallite size, stress) and electronic parameters (band gap, lifetime) on the photoelectrocatalysis and electron transport over CdSe electrodeposited inside TiO2-nanotubes (CdSe@TiO2NT) were investigated. Density functional theory (DFT) calculations of TiO2 were used to elucidate the electronic band structure and to correlate with experimental values. CdSe was grown by pulsed electrodeposition into previous and late thermal-treated TiO2NT (Sample-PTT and Sample-LTT, respectively) without blocking the nanotube's entrance. The Rietveld refinement method was used to obtain information from crystallographic data of each photoelectrode. The lattice strains calculated from the Rietveld analysis for Sample-PTT and Sample-LTT were 0.472 and 0.540, and the average volume of the TiO2-anatase unit cell increased from 133.235(0) angstrom(3) to 136.950(6) angstrom(3), respectively. Sample-PTT exhibited higher experimental electron lifetime, larger than 1.0 order of magnitude compared to Sample-LTT photoanodes. The band structures and DOS obtained by computational modelling showed theoretical band gap values of 2.54 eV and 2.75 eV, which were close to the experimental values. All studies evidenced a strong dependence of the electronic properties of the CdSe@TiO2 samples on their morphology, and, consequently, on their photoelectrochemical activity in water splitting. (AU)

• Processo FAPESP: 12/06778-0 - Investigação da formação eletroquímica de nanotubos-TiO2 e sua dopagem anódica
• Beneficiário: Milli Aline Sant Anna
• Modalidade de apoio: Bolsas no Brasil - Iniciação Científica
• Processo FAPESP: 10/05555-2 - Investigação da formação eletroquímica de nanotubos-TiO2 e sua aplicação em sistemas conversores de energia nanoarquiteturados
• Beneficiário: Renato Garcia de Freitas Sobrinho
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 12/10947-2 - Obtenção e caracterização de filmes finos de calcogenetos do tipo MBS (M = Ag ou Cu; B = In, Ga, Sb ou Tl; e S = S ou Se ) para aplicação em células fotovoltaicas
• Beneficiário: Francisco Willian de Souza Lucas
• Modalidade de apoio: Bolsas no Brasil - Doutorado