Utilizing the energy transfer mechanism to realize color tunable luminescence.

Bi 3+ /Eu 3+ co-doped phosphors can realize multi-color luminescence by adjusting the concentration ratio, which makes it possible to manually control the emission color. On this basis, a series of Bi 3+ /Eu 3+ co-doped phosphors SrLaGa 3 O 7 : x Bi 3+ , y Eu 3+ were prepared. The existence of energy transfer from Bi 3+ to Eu 3+ was verified by spectral analysis. The emission spectra of SrLaGa 3 O 7 : x Bi 3+ show a wide-band peaking at 472 nm. For SrLaGa 3 O 7 : x Bi 3+ , y Eu 3+ , the Bi 3+ → Eu 3+ energy transfer occurs and a series of sharp emitting peaks of Eu 3+ can be observed simultaneously. The relative luminescence intensity of Bi 3+ and Eu 3+ can be modulated by changing the relative concentrations of Bi 3+ and Eu 3+ . Using this mechanism, the color tunable luminescence of SrLaGa 3 O 7 : x Bi 3+ , y Eu 3+ from cyan, through white to orange, and finally to red is realized. By using a 320 nm UV chip and SLG:0.06Bi 3+ ,0.07Eu 3+ white phosphor, a white light-emitting diode (WLED) lamp was fabricated with chromaticity coordinates of (0.3199, 0.3083) and a color rendering index R a of 82. This indicates that the prepared sample is a very promising candidate in the LED field.