Emission color variation of Sr_3Si0_5:Ce~(3+), Li~+ phosphor for near-UV light-emitting diodes by co-doping with Mg~(2+) and Ba~(2+)

摘要

This paper reports the spectral variation of Sr_3Si0_5:Ce~(3+), Li~+ phosphor. It was synthesized by the conventional solid state method. The effects of calcining temperature and codoption of Mg~(2+) and Ba~(2+) on phase composition, structure, photoluminescence and thermal stability were firstly investigated in detail. Under the near-UV excitation of 415 nm,Sr_3Si0_5:Ce~(3+), Li~+ emits a bright greenish-yellow color centered at 532nm, which originates from 5d to 4f (~2F_(7/2) and ~2F_(5/2)) transition of Ce~(3+). The PL spectra show the different emission color variation with substituting Sr~(2+) cations with smaller Mg~(2+) or larger Ba~(2+), which makes it be applied as a color-tunable phosphor for LED based on near-UV chip/phosphor technology. Simultaneously, the thermal stability of (Sr,Ba)_3Si0_5:Ce~(3+), Li~+ phosphor is improved markedly.