Synthesis and optical properties investigation of blue-excitable red-emitting K2Bi(PO4) (MoO4):Pr3+ powders

A series of K2Bi(PO4) (MoO4) samples doped with 0.5%–50% Pr3+ was synthesized by a solid state synthesis method. The crystal phase was monitored by powder X-ray diffraction (XRD) and morphological characteristics were investigated by scanning electron microscopy (SEM). The luminescence properties: photoluminescence excitation and emission spectra, thermal quenching, and fluorescence lifetime values of Pr3+- doped samples were evaluated. The samples showed orange-red luminescence under near-UV excitation. It turned out that the profile of Pr3+ emission spectra is concentration and temperature dependent. Concentration quenching was observed in samples with higher than 1% Pr3+ concentration. Moreover, the calculated color coordinates showed good thermal stability in the 77–500 K temperature range. Based on the obtained results it can be concluded that prepared samples can be used in luminescent security pigments.