上海科技大学知识管理系统

Exploring new materials and enhancing their optical properties is an endeavor of great significance. Combining different types of optical functional groups, such as borate and tellurite anions, into the same compound can produce a new material of novel structure with enhanced optical performance. In the RE(iii)-Te(iv)-B-O system, a borate tellurite, namely, beta-LaTeBO5 (beta-LTBO) and a series of lanthanide borotellurites, namely, RETeBO5 (RE = Y, Gd, Tb), have been successfully synthesized by using a high-temperature solution method. beta-LTBO crystallizes in the space group of P21/c (no. 14) and its structure features [LaTeO3]infinity layers composed of La3+ cations and [TeO3]2- anions, where these layers are interconnected by 1[BO2]infinity chains consisting of [BO3]3- planar triangles to form a novel 3D structure. RETeBO5 (RE = Gd, Tb, Y) features 0D [Te2B2O10]6- clusters in which a central [Te2O6]4- dimer connects with two [BO3]3- groups on both sides of the dimer via Te-O-B bridges, and these 0D [Te2B2O10]6- clusters are interconnected by lanthanide ions to form the 3D structure. A phase transition from the beta phase to the alpha phase was observed at 700 degrees C for LaTeBO5 based on DSC and temperature-dependent XRD studies. Excitingly, the birefringence of beta-LTBO of 0.134@546 nm is much larger than that of RETeBO5 (RE = Y, Gd) (0.08, 0.074@546 nm), which is the largest in the borate tellurite system. Theoretical calculations indicate that the 1[BO2]infinity chains make a considerable contribution to the enhanced birefringence of beta-LaTeBO5. Furthermore, the luminescent and magnetic properties of RETeBO5 (RE = Y, Gd, Tb) were also studied. The present study proposes that the investigation of the metal-Te(iv)-B-O system may potentially result in the identification of numerous novel multifunctional materials.