The optical properties of manganese-activated zinc silicate Zn2(~_~/Mn2=SiQ are investigated using pulse selective photon excitation. The light response due to the 4T~g -~Alg transition is directly ]inked to the relative concentration of isolated Mn 2 § and Mn 2 § pairs in this structure. The decay curves can be fitted by a diffusion-limited relaxation mechanism by considering two typ.es of centers with radiative lifetimes T0 equal to 15 and 1.75 ms, respectively.

No abstract

No abstract

Luminescence, energy transfer, and upconversion mechanisms of nanophosphors (Y2O3 : Eu3+,Tb3+,Y2O3 : Tm3+,Y2O3 : Er3+,Yb3+) both in particle and colloidal forms were studied. The structure, phase, and morphology of the nanopowders and nanocolloidal media were determined by high-resolution TEM and X-ray diffraction. It was shown that the obtained nanoparticles have a round-spherical shape with average size in the range of 4 to 20 nm. Energy transfer was observed forY2O3 : Eu3+,Tb3+colloidal and powders, upconversion transitions were observed for bothY2O3 : Er3+andY2O3 : Er3+,Yb3+nanophosphors. The dependence of photoluminescence (PL) spectra and decay times on doping concentration has been investigated. The infrared to visible conversion of emission inY2O3 : Er3+,Yb3+system was analyzed and discussed aiming to be applied in the photonic technology.