title: A Study of Overheating of Thermostatically Controlled TiO2 Thin Films by Using Raman Spectroscopy.
abstract: In this study a classic Raman spectroscopy method is applied and the intensity ratio of Stokes and anti-Stokes peaks is used to measure the temperature of thermostatically controlled TiO2 thin films. In addition, three mathematical formulae are used and analyzed to estimate the temperature of the TiO2 thin films. Overheating of the samples above the thermostatically controlled temperature was observed while recording the Raman spectra, with a temperature increase of up to 30 K being detected. DFT-periodic calculations showed that the anatase (101) surface had a smaller band gap than bulk anatase. Thus, it can absorb the laser radiation with a wavelength of 532 nm that is used in the experimental setup. Part of the absorbed photon energy transfers into phonon energy, heating up the anatase phase, thus leading to the heating of the samples. Moreover, overheating of the samples indicates that the experimental method used in this study can lead to deviations in their real absolute temperature values.
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Juan Jesús
authors.initials: JJ
authors.lastname: Gallardo
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain. javier.navas@uca.es.
authors.forename: Javier
authors.initials: J
authors.lastname: Navas
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: David
authors.initials: D
authors.lastname: Zorrilla
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Alcántara
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Diego
authors.initials: D
authors.lastname: Valor
authors.affiliation: Departamento de Química Física, Facultad de Farmacia, Universidad de Sevilla, 41012, Sevilla, Spain.
authors.forename: Antonio
authors.initials: A
authors.lastname: Sánchez-Coronilla
authors.affiliation: Departamento de Física Aplicada I, Escuela Técnica Superior de Ingeniería Informática, av. Reina Mercedes, Universidad de Sevilla, 41012, Sevilla, Spain.
authors.forename: Norge Cruz
authors.initials: NC
authors.lastname: Hernández
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Concha
authors.initials: C
authors.lastname: Fernández-Lorenzo
authors.affiliation: Departamento de Química Física, Facultad de Ciencias, Universidad de Cádiz, 11510 Puerto Real, Cádiz, Spain.
authors.forename: Joaquín
authors.initials: J
authors.lastname: Martín-Calleja
keywords: Raman spectroscopy; TiO2; density functional calculations; nanoparticles; thin films