Nanocrystalline titanium dioxide films: Influence of ambient conditions on surface- and volume-related photoluminescence

Abstract

Magnetically doped semiconducting topological insulators J. Appl. Phys. 112, 063912 (2012) Effect of the thickness of the MoO3 layers on optical properties of MoO3/Ag/MoO3 multilayer structures J. Appl. Phys. 112, 063505 (2012) Local conductivity and the role of vacancies around twin walls of (001)−BiFeO3 thin films We report on systematic study of photoluminescence properties of nanocrystalline titanium dioxide films consisting of predominantly anatase nanoparticles with diameters larger than 13 nm. We measured photoluminescence under two selected excitation wavelengths ͑325 nm/442 nm, i.e., above/below band gap excitation͒, under different values of ambient air pressure ͑5-10 5 Pa͒, and in the temperature interval 10-300 K. On basis of our results, we are able to distinguish two different processes leading to photoluminescence: the exciton recombination and the recombination of carriers in the energy states related to the surface of nanocrystals. We propose microscopic models describing well the effects of temperature and ambient conditions on photoluminescence of nanocrystalline titanium dioxide films.

Photoluminescence of nanocrystalline titanium dioxide films loaded with silver nanoparticles

“…17,18 The PL of nc-TiO 2 is influenced by the addition of noble metal nanoparticles. 17,18 The PL of nc-TiO 2 is influenced by the addition of noble metal nanoparticles.…”

Comparative optical study of colloidal anatase titania nanorods and atomically thin wires

“…Size and doping effects on the absorption and emission properties of colloidal TiO 2 nanoparticles have been studied in detail by Serpone and co-workers, 16,17 and have been interpreted in terms of the co-existence of the band-edge 18 (or self-trapped exciton 19 ) recombination and the recombination involving midgap energy levels originating from oxygen vacancies (F-type color centres). 20,21 Recent studies by Knorr, McHale and co-workers [22][23][24] addressed the origin of the trap-related emission in nanocrystalline TiO 2 , classifying it into contributions from two spatially isolated trap-state distributions, resulting in recombination of trapped electrons or holes with oppositely charged mobile charge carriers in the valence or conduction band, respectively.…”

Clocking the Ultrafast Electron Cooling in Anatase Titanium Dioxide Nanoparticles

“…Our aim is to determine whether radiative (bimolecular) recombination processes take place at room temperature within the first 100 ps and, in this case, to evaluate the effective photoluminescence (PL) quantum yield for such processes. In the past, a number of works studied the radiative decay in anatase TiO 2 single crystals, thin films and NPs, both at low and room temperature [14][15][16][17][18][19][20]71]. Since anatase TiO 2 is an indirect bandgap insulator, band-to-band radiative recombination processes are unlikely, as the photoluminescence process requires phonon emission to conserve momentum.…”