Enhanced absorption of Sr3Lu2(BO3)4:Ce3+,Tb3+ phosphor with energy transfer for UV-pumped white LEDs

A series green emission phosphors Sr 3 Lu 2 (BO 3 ) 4 :Ce 3+ ,Tb 3+ (denoted as SLBO:Ce 3+ ,Tb 3+ ) with broad absorption band matching well with UV LED chip were synthesized by the solid–state reaction method. The phase and structure were analyzed with XRD , EDX , FT-IR measurements. The energy transfer between Ce 3+ and Tb 3+ in SLBO was proved by spectra and decay curves detailedly. The emission colors vary from blue to green by adjusting the ratio of Ce 3+ /Tb 3+ doped concentration. With temperature increasing, SLBO:Ce 3+ ,Tb 3+ phosphor shows well thermal stability that emission intensity retains 70% of its initial at 25 °C even temperature rising to 150 °C. The internal and external quantum efficiency of SLBO:3%Ce 3+ ,8%Tb 3+ are 77.5% and 34.8% under 340 nm excitation, respectively. Combining the as-synthesized SLBO:Ce 3+ ,Tb 3+ and red emission phosphor CaAlSiN 3 :Eu 2+ coated on a 365 nm UV chip, a warm white LEDs device with CRI of 83 was achieved. All the results indicate that the SLBO:Ce 3+ ,Tb 3+ phosphor has potential application in UV pumped white LEDs.