Ba2(Y,Sc)NbO6:Bi3+ solid solution nanocrystals: synthesis, photoluminescence properties, and white LEDs application

In the recent years, luminescent phosphor materials have contributed much to reduce the serious environmental problems such as environmental pollution, greenhouse effect, and energy crisis, but most of them commercially used for fabricating white LEDs are rare earth (RE) ions doped materials. Here, the non-RE Bi3+-doped Ba2(Y,Sc)NbO6 solid solution nanocrystals are prepared using a high temperature solid state route followed by a ball milling and griddle selection. Our experiments show that when the Y3+ ions are replaced by the Sc3+ ions, the obtained solid solution nanocrystals show a shift of X-ray reflection positions to higher angle, and the emission peaks from blue to blue-green. At the same time, a 1.35 time of PL intensity enhancement under 365 nm excitation is achieved in the Ba2(Y0.58,Sc0.4)NbO6:0.02Bi sample when compared to the Ba2Y0.98NbO6:0.02Bi sample. In addition, this optimal sample shows the quantum efficiency of 76% and good thermal stability with T50% value of 205 °C. By depositing the Ba2(Y0.58,Sc0.4)NbO6:0.02Bi and commercial red Sr2Si5N8:Eu2+ phosphors on a 365 nm UV LED chip at a driving current of 30 mA, a white LED device, with a CIE coordinates at (0.364, 0.379), a high color rendering index of 76.8 and luminous efficiency of 67 lm, and a low color temperature of 3469 K, is achieved.