Influence of Annealing on Europium Photoexcitation Doped into Nanocrystalline Titania Film Prepared by Magnetron Sputtering

Abstract

Nanocrystalline TinormalO2 films doped by Eu were obtained by low-pressure hot target reactive sputtering at different annealing temperatures and then characterized both structurally and optically. Strong emission assigned to europium ions was observed in the visible range. No emission related to the TinormalO2 matrix was detected, indicating an efficient excitation transfer from the matrix to the ions under nonresonant excitation. Europium emission strongly depends on the annealing temperature and reaches a maximum intensity for the sample annealed at 670K before dropping sharply at higher temperatures. Emission, absorption, and photoluminescence excitation measurements indicate that this effect results from the influence of defect formation at higher temperatures.

Influence of europium on structure modification of TiO2 thin films prepared by high energy magnetron sputtering process

“…The maximum of light emission at a wavelength of about 620 nm (red color) corresponds to Eu 3+ ions and is typical for most films doped with this rare element [36,[43][44][45]. We can observed also a peak split effect (two PL maxima at 615 nm and 622 nm, corresponding to 5 D 0  7 F 2 transitions) due to nanocrystalline surrounding of Eu 3+ ions [44]. Besides, at the PL -spectrum also four other emission lines (at 575 nm, 598 nm, 660 nm and 715 nm) related to the electron transitions between 5 D 0 and 7 F 0,1,3,4 levels of ions Eu 3+ can be seen.…”

“…% of the dopant. Most probably, this fact is related to greater efficiency of non-radiative recombination process via defect states of the titania matrix [44].…”

Influence of neodymium concentration on excitation and emission properties of Nd doped gallium oxide nanocrystalline films

“…Is this a direct excitation energy transfer from the grains to the lanthanide ions 4 or is this a defect mediated process? 8 For the latter one, two main processes can be responsible for the energy transfer mediated by the defect states, namely nonradiative dipole-dipole energy transfer ͑Förster-Dexter͒ ͑Ref. 26͒ or charge ͑electron/hole͒ transfer from donor/acceptor states to Nd ions.…”

Deposition Hydroxyapatite /Titania Composite on Ti-6Al-7Nb Alloy for Human Body Implants

“…At frequency domain 100 kHz -100 mHz, the measurement was carried out and the results are shown as bode plots of electrodes as represented in Fig. (4a-b).The electrochemical impedance spectroscopy result are shows equally and phase angle is a sensitive index to phenomena of surface occurred at electrolyte /electrode interface [3,13]. As it is represent, the spectra in Fig(4b) shows high capacitive worthy belong to typical of passive materials, as represented with angle phase a remain for wide range close to 90 o from medium to low frequencies.…”