A Study on the Luminescence Properties of CaAlBO[sub 4]:RE[sup 3+] (RE=Ce, Tb, and Eu) Phosphors

Wei-Ren Liu, Yi-Chen Chiu, Chien-Yueh Tung, Yao-Tsung Yeh, Shyue-Ming Jang, Teng-Ming Chen
2008 Journal of the Electrochemical Society  
A series of new phosphors of CaAlBO 4 :RE 3+ ͑RE = Ce, Tb, Eu͒ were synthesized by conventional solid-state reactions. The X-ray diffraction data indicate that a pure phase of CaAlBO 4 :RE 3+ can be successfully obtained. The photoluminescence ͑PL͒ spectra, quantum efficiency, and CIE coordinates of CaAlBO 4 :RE 3+ were investigated. The PL and PL excitation spectra indicate that the emission wavelengths of CaAlBO 4 :Ce 3+ are 372 and 398 nm ͑with full width at half maximum of 33 nm͒ attributed
more » ... f 33 nm͒ attributed to the 4f 6 5d-4f 7 transition of the Ce 3+ activator, respectively. CaAlBO 4 :Tb 3+ displays green emission at 483, 543, 584, and 620 nm, while CaAlBO 4 :Eu 3+ shows a dominating emission peak at 621 nm, which is attributed to the Eu 3+ 5 D 0 − 7 F 2 transition. The quantum efficiencies of optimized CaAlBO 4 :Ce 3+ , CaAlBO 4 :Tb 3+ , and CaAlBO 4 :Eu 3+ were found to be 43, 21, and 19%, respectively. The phosphors may provide a new kind of luminescent material under UV excitation. Recently, great interest in phosphors has resulted in rapid developments in the promising display and illumination technologies. For general lighting, photoluminescent ͑PL͒ materials including oxides, silicates, aluminates, aluminoborates, aluminosilicates, nitrides, borates, etc., play very important roles for potential applications in UV light-emitting diodes. Among these hosts investigated, borates are good candidates as host structure due to their low synthetic temperature, easy preparation, and high luminescent brightness. The luminescence properties of UV-excitable Eu 2+ -doped borate phosphors, such as O 9 X ͑M = Ca, Sr; X = Cl, Br͒, 7 have been reported in the literature. Apart from Eu 2+ -activated borates, several RE 3+ -doped borates have also been studied, such as BaAl 2 B 2 O 7 , 8 ͑Y,Gd͒BO 3 , 9 BaB 8 O 13 , 10 and CaAl 2 B 2 O 7 . 11, 12 Recently, the luminescent properties of RE 3+ -doped CaYBO 4 in the UV-vacuum UV spectral region have been reported by Wang and Wang 13 and Yang et al., 14 where RE is Eu 3+ , Tb 3+ , Gd 3+ , or Ce 3+ . To the best of our knowledge, the luminescence properties of rare-earth-ion-activated CaAlBO 4 are not reported yet. The aim of this work is to report our investigation results on the synthesis, PL, and color chromaticity of the new indigo-blue ͑CaAlBO 4 :Ce 3+ ͒, green ͑CaAlBO 4 :Tb 3+ ͒, and red phosphors ͑CaAlBO 4 :Eu 3+ ͒, and their corresponding spectroscopic properties under UV excitation. z
doi:10.1149/1.2953499 fatcat:r3fgme5ncjemjkgu4co4xx6fqa