Syntheses, crystal structure and luminescent properties of polyborates PbLnB7O13 (Ln = Gd, Sm) with a 2D [B7O13]∞ framework

• Published in: Journal of luminescence 2018-03, Vol.195, p.134-140
• Main Authors: Zhao, Dan, Ma, Fa-Xue, Liu, Bao-Zhong, Ma, Ming-Jie, Duan, Pei-Gao, Zhang, Li-Na, Zhang, Wei-Long
• Format: Article
• Language: English
• Subjects: Borate; Crystal structure; Phosphor; Photoluminescence; Rare earth
• ISSN: 0022-2313; 1872-7883
• DOI: 10.1016/j.jlumin.2017.10.016

Two new polyborates, PbLnB7O13 (Ln = Gd, Sm), have been prepared and their structures were determined by single crystal X-ray diffraction analysis. The results show that they are isostructure, crystallize in a non-centrosymmetric space group P21 and feature a 2D layer structure that is composed of [B7O13]∞ and [Ln]∞ layers. The [B7O13]∞ layer is constructed by BO3 triangles and BO4 tetrahedra with the fundamental building block of B7O17 (3∆4□: ∆). Moreover, a series of Sm-doped solid solutions PbGd1−xSmxB7O13 (x=0.005–1) were synthesized and their photoluminescence properties were studied. Under near-UV light (403nm) excitation, they exhibit intense orange emission centered at 602nm, due to the 4G5/2→6H7/2 transition of Sm3+ activator. We may expect that PbGd1−xSmxB7O13 could be used as a good orange phosphor pumped by near UV light LED chips. This work affords two new polyborates PbLnB7O13(Ln = Gd, Sm) that represent the first example of compound within PbO–Ln2O3–B2O3 ternary system. The structure features a 2D layer structure that is composed of [B7O13]∞ and [Tb]∞ layers stacking along the c-axis. Moreover, their solid solutions PbGd1−xSmxB7O13 (x = 0.005–0.12) were synthesized and the photoluminescence properties were studied. [Display omitted]