Realization of warm white light emitting in single phase Gd(PxV1−x)O4:y at% Sm3+,1 at% Bi3+ phosphor

A series of single phase, warm white light emitting phosphors, Gd(PxV1–x)O4:y at% Sm3+, with 1 at% Bi3+ doping concentration were synthesized by high temperature solid state method in this work. The experimental results indicate broadband cyan emission of Bi3+ and characteristic orange-red emission of Sm3+ can be effectively tuned by changing the ratios of PO43−/VO43− in Gd(PxV1–x)O4:1 at% Sm3+,1 at% Bi3+, and the energy transfer process among VO43−, Sm3+, Bi3+ also can be adjusted. Based on this, warm white light emitting can be realized by further optimizing the doping concentration of Sm3+ in the phosphors. At 423 K, the PL intensity of Gd(P0.7V0.3)O4:2 at% Sm3+,1 at% Bi3+ remains ～84.3% of the initial value at 293 K, while the measured quantum efficiency is 67.8%. EL spectrum analysis results of the fabricated white light emitting diode (wLED) based on a 310 nm UV-chip and Gd(P0.7V0.3)O4:2 at% Sm3+,1 at% Bi3+ phosphors imply low correlated color temperature (3132 K) and appropriate color-rending index (Ra = 82.7). These results demonstrate that Gd(P0.7V0.3)O4:2 at% Sm3+,1 at% Bi3+ is a good candidate for manufacturing UV-activated warm white light emitting diodes.