Influence of Gold Nanoparticles on Luminescence of Eu³⁺ Ions Sensitized by Structural Defects in Germanate Films

Abstract

This investigation shows new possibilities of gold nanoparticles using for rise of Ln 3+ ions luminescence in oxide matrixes at ultra violet synhrotron's excitation on example of germanate films doped with Eu and Au. It has been established that formation of gold nanoparticles (AuNPs) in such films leads to the enhancement of the Eu 3+ ions luminescence intensity by many times at excitation in broad absorption bands having λ max about 120 and 180 nm. The discovered effect is explained by joint influence of the following factors: (1) rise in the nonbridging oxygen hole centers (NBOHC) concentration as a result of breakage of the O−Eu bonds in the ≡Ge−О−Eu= bridges by the forming AuNPs; (2) nonradiative transfer of excitations from excitons to these centers; (3) effective sensitization of the Eu 3+ ions luminescence by the centers via the charge transfer (CT) state of the O 2− +Eu 3+ complexes; (4) increase in the optical path of the exciting radiation due to the intensification of light scattering by the AuNPs, and, possibly,(5) promoting by the AuNPs of excitations transfer in the exciton−NBOHC−(O 2− +Eu 3+ ) system in the nanoparticles field as well as weakening of reverse passivation of the hole centers by the hydrogen atoms formed on the breakage of the end OH − groups under the action of UV radiation.

Influence of Golden Nanoparticles on the Incorporation of Eu2+ into BaI2 and Defect Concentration

“…In particular, the incorporation of Au ions into BaBrCl:Eu single crystals leads to the enhancement of photoluminescence intensity and reduces long afterglow. Similar improvement of luminescent properties has also been previously observed in Eu-activated germanate films with golden nanoparticles (GNPs) [24][25][26]. The co-doping with nanoparticles may also enable radiation absorption in other regions of the spectrum, while the exact absorption spectrum may be tuned by varying the size and surface morphology of the nanoparticles used [27,28].…”

Luminescence mechanisms in the 2V2O5-xLi2O-(98-x)B2O3 glass matrices developed for creation of efficient glass-ceramic materials

“…For all the applied excitations, intensity of luminescence is distinctively increased with increase of concentration of the Li 2 O component. Spectra of the La 0.3 Eu 0.7 VO 4 -doped samples contain also narrow lines in the 570-720 nm spectral range which correspond to the well-known emission of the Eu 3+ ions [30][31][32]. Peak intensity of the Eu 3+ emission is more than 10 times higher when compared with the wide band emission.…”

Pulsed laser deposition of the LaVO4:Eu, Ca nanoparticles on glass and silicon substrates

“…Comparing results of SEM study and optical metrology, we should conclude that in despite of higher thickness of films on glass substrates, they contain a lower density of agglomerated inclusions. Therefore, the PLD technology allows to obtain very thin films of good quality from the vanadate nanoparticles, especially if compare with such methods as sol-gel deposition, spincoating, reactive sputtering, and liquid phase epitaxy (Chukova et al, 2019b;Zhu et al, 2018;Malashkevich et al, 2016;Nakajima et al, 2008;Zorenko et al, 2005). Investigation of reflection and transmittance (for the samples on glass substrates) spectra was carried out to estimate contributions of the film layers in spectral properties of the obtained samples.…”

“…Thin films of oxide phosphors can be prepared by various methods such as chemical vapor deposition, sol-gel deposition, spin-coating, reactive sputtering, molecular beam epitaxy, liquid phase epitaxy, etc. (Higuchi et al, 2011;Inada et al, 2018;Malashkevich et al, 2016;Zorenko et al, 2005). A good way to save luminescent properties of vanadate nanoparticles is pulsed laser deposition (PLD) of films .…”