A Promising Deep Ultraviolet Nonlinear Optical Crystal Activated by the Ordered Structure Design
Haonan Liu, Xuming Zhai, Xinru Li, Hongping Wu, Zhanggui Hu, Jiyang Wang, Yicheng Wu, Hongwei Yu
Abstract
Abstract Deep‐ultraviolet nonlinear optical (DUV NLO) crystals play a vitally important role in many scientific and technological fields, yet their rational design remains an ongoing challenge. Here, through utilizing the ordered structure design, a new KBe 2 BO 3 F 2 ‐like DUV transparent NLO crystal Cs 2 KY(B 3 O 6 ) 2 has been successfully designed and synthesized, in which we first use the largest π ‐conjugated B 3 O 6 functional groups to substitute the BO 3 to maximize the second‐harmonic generation (SHG) response and utilize the K/YO 6 connecting groups to replace two BeO 3 F groups to optimize the layer connections. Eventually, Cs 2 KY(B 3 O 6 ) 2 exhibits not only the largest SHG responses in KBe 2 BO 3 F 2 ‐like DUV borates but also the best growth rate along c axis (the strong layer‐habit along c axis has been being the greatest obstacle to prohibit the practical application of KBe 2 BO 3 F 2 and its derivative). Clearly, the substitution from BO 3 triangles to similar topological B 3 O 6 groups and from (BeO 3 F) 2 groups to similar topological K/YO 6 octahedra can better modulate the functional properties of materials in the larger scale. That results in the superior comprehensive properties of Cs 2 KY(B 3 O 6 ) 2 and makes it a promising DUV NLO crystal. Therefore, the ordered structure design provides some new insights for assembling the functional and connecting groups to rationally design materials with high‐performance.