Luminescent properties of Eu3+-activated lithium rare earth borates and oxyborates

• Published in: Journal of luminescence 2003, Vol.101 (1-2), p.1-10
• Main Authors: JUBERA, V, CHAMINADE, J. P, GARCIA, A, GUILLEN, F, FOUASSIER, C
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Material chemistry; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Other solid inorganic materials; Photoluminescence; Physics
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/S0022-2313(02)00335-6

The luminescence characteristics of Eu3+ in the borates Li6Y(BO3)3 and Li3La2(BO3)3 and the recently discovered oxyborates LiLa2O2BO3, LiLn6O5(BO3)3 (Ln=Y,Gd) and Li2Lu5O4(BO3)3 have been investigated and compared to those in the borates LnBO3 (Ln=La,Y) and the oxyborates “Ln3BO6” (Ln=La,Gd). The probability of electric dipole f–f transitions is generally markedly higher in oxyborates than in borates. This is ascribed to the highly anisotropic environment of rare earth ions and the low position of the charge transfer states. Consequently, the Eu3+-activated oxyborates are characterized by a deeper red emission and faster decay. The luminescence characteristics of Eu3+ in the borates Li6Y(BO3)3 and Li3La2(BO3)3 and the recently discovered oxyborates LiLa2O2BO3, LiLn6O5(BO3)3 (Ln=Y,Gd) and Li2Lu5O4(BO3)3 have been investigated and compared to those in the borates LnBO3 (Ln=La,Y) and the oxyborates “Ln3BO6” (Ln=La,Gd). The probability of electric dipole f–f transitions is generally markedly higher in oxyborates than in borates. This is ascribed to the highly anisotropic environment of rare earth ions and the low position of the charge transfer states. Consequently, the Eu3+-activated oxyborates are characterized by a deeper red emission and faster decay.