Tetrahedron-based deep-ultraviolet nonlinear optical crystal with optimized KBeBOF-like structure and disordered cations

• Published in: New journal of chemistry 2023-04, Vol.47 (16), p.7521-7526
• Main Authors: Xu, Junxin, Sha, Hongyuan, Shang, Yanran, Wang, Zujian, Su, Rongbing, He, Chao, Yang, Xiaoming, Long, Xifa
• Format: Article
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/d3nj01114c

On account of the development of deep-ultraviolet (DUV) nonlinear optical (NLO) crystals, tetrahedron-based compounds have attracted more and more attention, due to their large band gap. Thus, it is urgent to study a lot of these crystals for conducting structural optimization to achieve a balance of optical properties. Thus, this paper designs and obtains the Li 2 NH 4 Rb(SO 4 ) 2 crystal, an alkali metal sulfate, which is composed of an optimized KBe 2 BO 3 F 2 -like structure and disordered Rb and [NH 4 ] cations. It exhibits a strong second-harmonic generation (SHG) response of 2 × KH 2 PO 4 , a large band gap of 7.56 eV and a favorable growth habit to large crystals, simultaneously. Thus, the Li 2 NH 4 Rb(SO 4 ) 2 crystal is a typical tetrahedron-based DUV NLO example. The coordination of the optimized KBe 2 BO 3 F 2 -like structure and the disordered cations results in the strong SHG response. This structural design strategy will facilitate the exploration of novel DUV NLO crystals. The Li 2 NH 4 Rb(SO 4 ) 2 crystal exhibits a strong second-harmonic generation response of 2 × KH 2 PO 4 and a large band gap of 7.56 eV.