K+ and Ce3+ co-doped Ba2.96P4O13:0.04Eu2+ white light emitting phosphor: Crystal phase transformation analysis and luminescence properties

In this work, a tunable white light-emitting Ba 2.96–2 x K x Ce x P 4 O 13 :0.04Eu 2+ ( x = 0.00–0.16) phosphor was synthesized via solid-state reactions. The phosphor phase selection depends on Ce 3+ doping concentration in Ba 3 P 4 O 13 host. Under 340 nm excitation, Ba 2.96 P 4 O 13 :0.04Eu 2+ phosphor exhibits a broad asymmetric cyan emission centered around 450 nm in the absence of Ce 3+ doping‌. However, when Ce 3+ ions are introduced, the emission spectrum of Ba 2.96 P 4 O 13 :0.04Eu 2+ phosphor becomes broader and the maximum emission peak shifts to 550 nm. This phenomenon is attributed to the phase transition of Ba 2.96 P 4 O 13 :0.04Eu 2+ from low-temperature phase to high-temperature phase. Temperature-dependent photoluminescence measurements reveal that low-temperature phase phosphors exhibit superior thermal stability compared to high-temperature phase phosphors. Eventually, a white light-emitting diode device was fabricated by combining the Ba 2.64 Ce 0.16 K 0.16 P 4 O 13 :0.04Eu 2+ phosphors with 365 nm light-emitting diode (LED) chip, which exhibits a high color rendering index of 91.61 and a low correlated color temperature of 4230 K. As reported, white-emitting Eu 2+ and Ce 3+ co-doped phosphors have potential applications in solid-state lighting. The crystal-phase engineering approach provides a guide for optimizing and designing novel single composition white-emitting phosphor materials.