A novel single-phase Na3.6Y1.8(PO4)3:Bi3+,Eu3+ phosphor for tunable and white light emission

A new type of Bi3+,Eu3+ single- and co-doped Na3.6Y1.8(PO4)3 phosphate phosphors were manufactured using conventional high-temperature solid-state reaction technique to explore their application for solid-state lighting. The crystal structure, luminescent properties, luminescent mechanism and quantum efficiency were thoroughly explored. Results show that there are two crystallization sites for Bi3+ and Eu3+ ions. Upon the excitation of 342 and 373 nm, Bi3+ single-doped phosphors exhibit green and blue emission, derived from the 3P1 to 1S0 transition of Bi3+ located in different occupancy sites. Thanks to radiative energy transfer process from Bi3+ to Eu3+, adjustable emission could be acquired by altering Eu3+ content in co-doped phosphors. Pure white-light emission with quantum efficiency value of 22.9% can be realized in Na3.6Y1.8(PO4)3:0.01Bi3+,0.1Eu3+ sample and the integrated intensity of white light emission at 417 K remains 85% of that at room temperature. Our results indicate that Na3.6Y1.8(PO4)3:Bi3+,Eu3+ phosphors have feasible application in high-power ultraviolet driven solid-state lighting.