Luminescence properties and determination of optimal RE3+ (Sm3+, Tb3+ and Dy3+) doping levels in the KYP2O7 host lattice obtained by combustion synthesis
Abstract
The β-KYP2O7 powders doped with Sm3+, Tb3+ and Dy3+ were obtained using a one-step urea-assisted combustion method. Their structural properties were characterized by X-ray diffraction (XRD) whereas spectroscopic properties like excitation, emission and luminescence kinetics were investigated at room temperature. β-KYP2O7 doped with Sm3+ and Dy3+ showed concentration quenching above 2 mol% of dopants whereas Tb3+ containing materials could be doped with higher concentrations. The main mechanisms of concentration quenching were identified as dipole–dipole for Sm3+ and Dy3+. Both dopants due to the abundant energy levels are strongly prone to quenching due to the non-radiative CR process whose efficiency strongly increases with the concentration of optically active ions. In the case of Tb3+ emission from both 5D3 and 5D4 levels was recorded. The 5D3 level vastly depopulates due to the CR process upon increase of the Tb3+ content whereas the slight 5D4 emission remains stable up to 5 mol%.