title: A new UV nonlinear optical material CsZn2B3O7: ZnO4 tetrahedra double the efficiency of second-harmonic generation.
abstract: A new noncentrosymmetric borate CsZn2B3O7 was synthesized by the solid-state reaction techniques. The crystals were obtained by flux method and are of block shape without layering tendency. Single-crystal X-ray diffraction analysis reveals that the crystal structure is composed of [Zn2BO5]∞ two-dimensional layers that are bridged by [B3O6](3-) groups to form a three-dimensional framework with one-dimensional channels occupied by Cs(+) cations along the a and c axes. Thermal analysis indicates that CsZn2B3O7 melts incongruently. UV-visible-near-IR diffuse reflectance spectrum gives a short absorption edge at 218 nm. CsZn2B3O7 is phase-matchable, with a powder second-harmonic generation (SHG) efficiency of 1.5 × KDP (KDP, potassium dihydrogen phosphate) at 1064 nm, based on the Kurtz-Perry method. These results show that CsZn2B3O7 may have prospects as a UV nonlinear optical material. Interestingly, the SHG efficiency of CsZn2B3O7 is about twice that of γ-KBe2B3O7, a structurally analogous alkaline and alkaline earth borate. First-principles calculations combined with atom-cutting analysis reveal that the ZnO4 tetrhedral groups in CsZn2B3O7 account for the SHG enhancement.
authors: Key Laboratory of Optoelectronic Materials Chemistry and Physics, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences , Fuzhou, Fujian 350002, China.
authors: Sangen
authors: S
authors: Zhao
authors: Jia
authors: J
authors: Zhang
authors: Shu-quan
authors: SQ
authors: Zhang
authors: Zhihua
authors: Z
authors: Sun
authors: Zheshuai
authors: Z
authors: Lin
authors: Yicheng
authors: Y
authors: Wu
authors: Maochun
authors: M
authors: Hong
authors: Junhua
authors: J
authors: Luo