Luminescence Properties and Energy Transfer of Ce³⁺,Tb³⁺‐Coactivatedβ‐SiAlON Phosphors

Abstract

Using the solid-state reaction method, Ce 3+ ,Tb 3+ -coactivated Si 5 AlON 7 (Si 6Àz Al z O z N 8Àz , z = 1) phosphors were successfully synthesized. The obtained phosphors exhibit high absorption and strong excitation bands in the wavelength range of 240-440 nm, matching well with the light emitting-diode (LED) chip. The ET from Ce 3+ to Tb 3+ ions in Si 5 AlON 7 :Ce 3+ ,Tb 3+ has been studied and demonstrated by the luminescence spectra and decay curves. Moreover, the phosphors show tunable emissions from blue to green by tuning the relative ratio of the Ce 3+ to Tb 3+ ions. Thermal quenching properties of Si 5 AlON 7 :Ce 3+ ,Tb 3+ had also been investigated and the quenching temperature is 190°C. These results show that Si 5 AlON 7 :Ce 3+ ,Tb 3+ could be a promising candidate for a single-phased color-tunable phosphor applied in UV-chip pumped LEDs.

Synthesis of mono-phase La 2 Si 6 O 3 N 8 :Ce 3+ ,Tb 3+ blue-green phosphors with direct silicon nitridation and their photoluminescence properties

“…8 [20]. The most intense emission peak at 546 nm was due to the 5 D4-7 F5 transition, while the other peaks at 492, 592, and 626 nm were due to the transitions 5 D4-7 F6, 5 D4-7 F4, and 5 D4-7 F3, respectively [21]. The strong green emission at 546 nm, caused by excitation at 379 nm, demonstrates that these La2Si6O3N8:Tb 3+ phosphors are promising candidates for UV LED.…”

“…The energy levels in Fig. 10 The energy transfer efficiency (ηT) from the sensitizer (Ce 3+ ) to the activator (Tb 3+ ) can be expressed by the equation [21,32]: (2) where IS and IS0 are the luminescence intensities of the sensitizer (Ce 3+ ) with and without the activator (Tb 3+ ) present, respectively. The value of ηT for La1.8-ySi6O3N8:0.2Ce 3+ ,yTb 3+ (y = 0-0.5) is plotted as a function of y in Fig.…”

“…In the case of dipole-dipole interactions, the critical energy transfer distance from a sensitizer to an accepter is given by the formula [21]:…”