Effect of structural and Eu3+ amount in TiO2 semiconductor material on downconversion photoluminescence properties

Arantes, Danilo C.; Mayrinck, Caroline de; Santos, Jordana Dias dos; Maia, Lenize F.; Oliveira, Luiz Fernando Cappa de; Schiavon, Marco A.; Pasquini, Daniel; Lima, Ronaldo Cintra; Morais, Luiz C. de; Esbenshade, Jennifer; Ferrari, Jefferson Luis

doi:10.1016/j.optmat.2018.12.020

Cited by 8 publications

(2 citation statements)

References 27 publications

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“…ART of TiO 2 at high temperature could be controlled by the addition of metal ions, suitable chemical modifiers and an appropriate synthesis method [13]. Doping with metal ions is a one of the profitable ways to retard the ART [14,21,[23][24][25][26][27][28][29][30][31]. Metal ions could improve the thermal stability of TiO 2 through the reduction in contact points, and nucleation sites [32].Generally, doping of an element with higher oxidation state compared to Ti 4+ would improve charge carrier separation on the photocatalyst surface [33].…”

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Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

et al. 2020

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This work outlines an experimental and theoretical investigation of the effect of molybdenum (Mo) doping on the oxygen vacancy formation and photocatalytic activity of TiO 2 . Analytical techniques such as x-ray diffraction (XRD), Raman, x-ray photoelectron spectroscopy (XPS) and photoluminescence (PL) were used to probe the anatase to rutile transition (ART), surface features and optical characteristics of Mo doped TiO 2 (Mo-TiO 2 ). XRD results showed that the ART was effectively impeded by 2 mol% Mo doping up to 750°C, producing 67% anatase and 33% rutile. Moreover, the crystal growth of TiO 2 was affected by Mo doping via its interaction with oxygen vacancies and the Ti-O bond. The formation of Ti-O-Mo and Mo-Ti-O bonds were confirmed by XPS results. Phonon confinement, lattice strain and non-stoichiometric defects were validated through the Raman analysis. DFT results showed that, after substitutional doping of Mo at a Ti site in anatase, the Mo oxidation state is Mo 6+ and empty Mo-s states emerge at the titania conduction band minimum. The empty Mo-d states overlap the anatase conduction band in the DOS plot. A large energy cost, comparable to that computed for pristine anatase, is required to reduce Mo-TiO 2 through oxygen vacancy formation. Mo 5+ and Ti 3+ are present after the oxygen vacancy formation and occupied states due to these reduced cations emerge in the energy gap of the titania host. PL studies revealed that the electron-hole recombination process in Mo-TiO 2 was exceptionally lower than that of TiO 2 anatase and rutile. This was ascribed to introduction of 5s gap states below the CB of TiO 2 by the Mo dopant. Moreover, the photo-generated charge carriers could easily be trapped and localised on the TiO 2 surface by Mo 6+ and Mo 5+ ions to improve the photocatalytic activity. coatings [8,9]. The most commonly existing crystalline polymorphs of TiO 2 are anatase, rutile and brookite [10][11][12]. Anatase is accepted to be the more active phase of TiO 2 and is preferred by the ceramic industries to fabricate light active antimicrobial indoor building materials such as ceramics, glass, tiles and sanitary surfaces [13,14]. This requires thermal stability of the anatase phase under typical ceramic processing conditions. TiO 2 anatase is mainly fabricated at low calcination temperatures (∼500°C) to prevent the anatase to rutile phase transition (ART) [15][16][17], which produces the less photo-active rutile phase. The photo-activity of anatase arises from its appropriate band edge positions, electron affinity, ionisation potential, and the long lifetime of charge carriers [10,12,18]. Moreover, transient photo-conductance analysis has revealed that the electron-hole recombination phenomena in anatase (101) phase is much slower compared to rutile (110), which is credited in part to the indirect band gap of anatase [11,19].The unit cells of anatase and rutile phases are composed of TiO 6 octahedra with titanium atoms at the centre and oxygen atoms at the vertices [20]. Both anatase and rutile have a t...

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Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

et al. 2020

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“…Neste caso, o aumento da luminescência foi atribuído a colocação de íons de Er 3+ em sítios de baixa simetria dos nanocristais de TiO2; o aumento da temperatura favoreceu esta situação pois maior concentração de NPs de TiO2 foram criadas. Tal efeito foi também reportado para íons de Eu 3+ [44].…”

Section: Nanopartícula De Titâniaunclassified

Síntese e caracterização de compósitos metal-dielétrico com vidros TeO2-ZnO dopados com íons de Ho3+/Tm3+/Yb3+ e nanopartículas de TiO2 e Ag para dispositivos de luz sintonizáveis no visível e geração de luz branca.

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AgradecimentosÀ ilustríssima Prof. Dra. Luciana Reyes Pires Kassab pela paciência, dedicação, atenção e apoio dado ao longo deste trabalho.Ao Me José Augusto Martins Garcia, auxiliar docente do Laboratório de Materiais Fotônicos e Optoeletrônicos (LTMFO), pela ajuda e paciência. Agradeço pelos momentos de aula e filosofia que tivemos nesse último ano.À Me Camila Dias da Silva Bordon pelo auxílio em todas as caracterizações ópticas realizadas e pelos momentos de risadas. Ao Me. Daniel K. Kumada pela colaboração nas medidas de luminescência e momentos de risadas.Ao Mestre Marcos Nishimura, pelos momentos de descontração, auxílio e amizade.Ao Guilherme Mattos, pela parceria e apoio contínuo. Foi uma honra poder realizar o mestrado na mesma época.À FATEC-SP, pelo espaço cedido pelo Laboratório de Tecnologia em Materiais Fotônicos e Optoeletrônicos à pesquisa

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TiO2 doped with europium (Eu): Synthesis, characterization and catalytic performance on pesticide degradation under solar irradiation

et al. 2022

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Effect of structural and Eu3+ amount in TiO2 semiconductor material on downconversion photoluminescence properties

Cited by 8 publications

References 27 publications

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Síntese e caracterização de compósitos metal-dielétrico com vidros TeO2-ZnO dopados com íons de Ho3+/Tm3+/Yb3+ e nanopartículas de TiO2 e Ag para dispositivos de luz sintonizáveis no visível e geração de luz branca.

TiO2 doped with europium (Eu): Synthesis, characterization and catalytic performance on pesticide degradation under solar irradiation

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Effect of structural and Eu3+ amount in TiO2 semiconductor material on downconversion photoluminescence properties

Cited by 8 publications

References 27 publications

Mo doped TiO2: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO2: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Síntese e caracterização de compósitos metal-dielétrico com vidros TeO2-ZnO dopados com íons de Ho3+/Tm3+/Yb3+ e nanopartículas de TiO2 e Ag para dispositivos de luz sintonizáveis no visível e geração de luz branca.

TiO2 doped with europium (Eu): Synthesis, characterization and catalytic performance on pesticide degradation under solar irradiation

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Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity

Mo doped TiO₂: impact on oxygen vacancies, anatase phase stability and photocatalytic activity