Synthesis of Gd[sub 1−x]Eu[sub x]Al[sub 3](BO[sub 3])[sub 4] (0<x≤1) and Its Photoluminescence Properties under UV and Vacuum Ultraviolet Regions

Abstract

Single phase europium-activated gadolinium aluminum borate, Gd 1Ϫx Eu x Al 3 ͑BO 3 ) 4 (0 р x р 1) was obtained by the evaporation of its nitrate solution, and calcination at 900 to 1100°C in air. All the solid solution was identified as the isomorphs of huntite. Eu 3ϩ activated GdAl 3 ͑BO 3 ͒ 4 showed intense red emission with CIE chromaticity coordinates of ͑0.645, 0.330͒ under 147 nm excitation. According to the excitation and emission spectra, the red emission of Eu 3ϩ was decreased under excitation of the vacuum ultraviolet ͑VUV͒ region ͑158-160 nm͒, and increased under excitation UV region ͑258-260 nm͒ with the increase of Eu 3ϩ concentration. In comparison with the absorption data of borates, the 158 nm excitation peak was assigned to the energy level of BO 3 groups. In excitation spectra, the sharp 274 nm peak, corresponding to the 8 S 72 → 6 I 2/11 transition of Gd 3ϩ in addition to the f-f transitions of Eu 3ϩ were observed. Consequently, the emission of Eu 3ϩ was induced by the energy transfer of VUV excitation to the activator Eu 3ϩ ions via the co-activator Gd 3ϩ in GdAl 3 ͑BO 3 ͒ 4 .

Interpretation of europium(III) spectra

“…Recording an excitation spectrum is the preferred method for determining these energy levels in powder samples or in very diluted crystals or solutions, for which measurement of the absorption spectrum is difficult or even impossible. Measurement of the excitation spectrum is also the preferred method for determination of the energy levels of a lanthanide ion in the vacuum ultraviolet (VUV) region [446,[532][533][534][535][536][537][538][539][540]. The main disadvantage of an excitation spectrum is that it cannot be used for studies of intensities of f-f transitions.…”

Luminescence characteristics of undoped and Eu‐doped GdCa4O(BO3)3 single crystals and nanopowders

“…They show high ultraviolet (UV) transparency and nonlinear properties. In the past, many investigations have been made on borate complexes LnAl 3 (BO 3 ) 4 Eu 3+ (Ln = Gd 3+ Y 3+ ) under UV and vacuum ultraviolet (VUV) excitation [1][2][3][4]. Other interesting borate complex is gadolinium calcium oxoborate GdCa 4 O(BO 3 ) 3 (GdCOB).…”

Synthesis of Nanosized Luminescent Materials and Their Photoluminescence under VUV Excitation

“…All spectra in Fig. 10 consists of sharp lines ranging from 580 to 700 nm, which are associated with the transitions from the excited 5 3+ by adjusting the PH value. What is more, the PL properties could also be adjusted.…”

“…1). 5 The Specific emission process is not clear. So current research about VUV phosphor focus on these aspects: Improvement on traditional phosphors, development of new phosphors and investigation of luminescence mechanism.…”

“…One is the BO 3 group absorption (BA) band (peak at about 145 nm) and the other is the Eu 3+ 4f-5d transition band (peak at about 154 nm). 5 Fig. 16.…”