Up-conversion green emission of Yb 3+ /Er 3+ ions doped YVO 4 nanocrystals obtained via modified Pechini's method

Abstract A series of lanthanide doped yttrium vanadates were prepared by Pechini's method (sol-gel process). The as-prepared precursors, in the presence of citric acid, were calcined in the temperature range of 600–900 °C. The obtained products were composed of small nanoparticles, in the size range of 20–50 nm, depending on the annealing temperature, exhibiting a bright green up-conversion emission, under NIR laser irradiation, and emission lifetimes in the range of 4.7–18.3 μs. Their structural, morphological and spectroscopic properties were investigated in detail by XRD, HR-TEM including FFT analysis, EDX and spectroscopic techniques (emission, power dependence and emission kinetics). The luminescence quenching phenomenon, manifested in a decrease of up-conversion intensity and shortening of emission lifetime, was observed with increasing of the Yb 3+ ion concentration and decreasing the particle size. The optimal concentration of the Yb 3+ ions was found to be 15 mol% (YVO 4 : Yb 3+ 15 mol%, Er 3+ 2 mol%).