Optical and luminescence characteristics of Eu3+ doped zinc bismuth borate (ZBB) glasses for red emitting device

Abstract Zinc bismuth borate (ZBB) glasses with chemical composition of (60 − x ) B 2 O 3 : 30Bi 2 O 3 : 10ZnO: x Eu 2 O 3 for different Eu 2 O 3 concentrations of x = 1, 3, 5, 7 and 9 mol% were prepared by the conventional melt quenching technique. The density and molar volume of the glasses have been found to increase with Eu 2 O 3 concentration. The IR studies indicated that these glasses were made up of [BiO 3 ], [BO 3 ], [BO 4 ] and [BO] basic structural units. The absorption spectra had revealed two intense bands due to 7 F 0 → 7 F 6 (2076 nm) and 7 F 1 → 7 F 6 (2198 nm) transitions in the NIR regions. The fractional populations of the ( 7 F 0 ) and ( 7 F 1 ) ground state were 65% and 35% , respectively. Five luminescence bands were observed at 579 nm ( 5 D 0 → 7 F 0 ), 589 nm ( 5 D 0 → 7 F 1 ), 613 nm ( 5 D 0 → 7 F 2 ), 651 nm ( 5 D 0 → 7 F 3 ) and 696 nm ( 5 D 0 → 7 F 4 ), when excited by a 465 nm source, the most intense red emission was found at 613 nm. A shorter decay time of 5 D 0 excited state was found with increasing of Eu 3+ concentration as more asymmetries were created around Eu 3+ . For comparison, further investigations were carried out with two other glass structures; bismuth borate glass (BB) and zinc borate glass (ZB), doped with Eu 3+ in the same range. The ZBB glasses have exhibited with the highest emission intensity especially at 613 nm; the intensity for the ZBB was around 7 times of the ZB and twice of the BB glasses.