Enhancement of luminescence properties and the role of ZnO in Tb3+ ions doped zinc aluminum phosphate glasses

Abstract Terbium ion doped zinc aluminum phosphate (ZAP) glasses with composition (90− x )((90− y )P 2 O 5 –10Al 2 O 3 – y ZnO)– x Tb 2 O 3 ( x =0.5–9 in mol% and y =30, 35, 40 in mol%) have been prepared by melt quenching method, and the effects of the Tb 2 O 3 and ZnO content on the luminescence properties have been studied by photoluminescence spectroscopies. It was found that the green emission peaked at 544 nm is significantly enhanced under higher Tb 2 O 3 content, meanwhile the sensitization effect of ZnO content is confirmed from the enhanced main emission. The quenching effect attributed to the resonant energy transfer through the cross-relaxation mechanism is observed when Tb 2 O 3 concentration is beyond 2.5 mol% due to the fact that more Tb 3+ ions enhance the 4f→5d and 4f→4f electronic transitions through the dipole–dipole (d–d) interaction. Also, ZnO plays a role of the disperser to prevent non-radiative de-excitation process. A characteristic luminescence image of the (100− x )(60P 2 O 5 –10Al 2 O 3 –30ZnO)· x Tb 2 O 3 series glasses under UV excitation at 366 nm is presented for the first time, and the transition of luminescence suggests that the Tb 3+ -doped ZAP glasses are suitable for green and dual-color blue/green LED applications by modulation of Tb and ZnO composition.