Three Borates Belonging to the A(I)<sub>7</sub>Ae(II)Re(III)<sub>2</sub>B<sub>15</sub>O<sub>30</sub> Family as Promising Nonlinear Optical Crystals
Chengfa Wu, Yu Dang, Jianbang Chen, Xueling Hou, Hongsheng Shi
Abstract
High Resolution Image Download MS PowerPoint Slide Three borate crystals, namely, Rb 7 CaY 2 B 15 O 30, NaRb 6 CaY 2 B 15 O 30, and LiRb 6 CaY 2 B 15 O 30, belonging to the A(I) 7 Ae(II)Re(III) 2 B 15 O 30 family, were synthesized by the high-temperature solution method under open systems. The space groups of Rb 7 CaY 2 B 15 O 30 and NaRb 6 CaY 2 B 15 O 30 are both R 32, while the space group of LiRb 6 CaY 2 B 15 O 30 is C 222 1 . The anion frames are all zero-dimensional clusters composed of isolated [B 5 O 10 ] units. Mixed metallic elements with three distinct valence states fill the gaps between anion groups to balance charge and form overall three-dimensional structures. The ultraviolet cutoff edges are lower than 195, 185, and 200 nm for Rb 7 CaY 2 B 15 O 30, NaRb 6 CaY 2 B 15 O 30, and LiRb 6 CaY 2 B 15 O 30, respectively. The second-harmonic generation response of Rb 7 CaY 2 B 15 O 30 and NaRb 6 CaY 2 B 15 O 30 is 1.4 and 1.2 × KDP, which makes them promising candidates for nonlinear optical crystals. A detailed discussion of the correlation between the structure and optical properties is presented through first-principles calculations.