LiB2O3F: A Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material Designed Based on a Boron-Rich Strategy
LiB2O3F: A Beryllium-Free Deep-Ultraviolet Nonlinear Optical Material Designed Based on a Boron-Rich Strategy
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LiB2O3F：基于富硼策略设计的无铍深紫外非线性光学材料
DOI：
10.1021/acs.chemmater.1c01369
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发表时间：
2021-06-14
影响因子：
8.6
通讯作者：
Mao, Jiang-Gao
中科院分区：
文献类型：
--
作者：
Hu, Chun-Li;Chen, Jin;Mao, Jiang-Gao
探索实用的深紫外（DUV）非线性光学（NLO）材料仍然是迫切需要和严峻的挑战。从理想的六方（BO）（无穷大）层状几何结构出发，我们采用富硼策略引入高比例的二次谐波产生（SHG）活性B-O（F）基团来设计潜在的DUV NLO材料。采用进化算法结合密度泛函理论方法预测了五种基于LiB2O3F（LBF）体系的新型非中心对称3D晶体结构。得益于高比例的B-O(F)活性基团和良好的排列，极性LBF-I和III晶体表现出最佳的综合性能，在所有指标上都超过了显着的KBe2BO3F2 (KBBF)：I的倍频系数d(11)为0.88 pm/V (III为0.74 pm/V)，几乎是KBBF (0.47 pm/V)的2倍，并且它们的带隙更宽，带隙更大。与 KBBF (161 nm) 相比，双折射导致相位匹配波长更短（I 为 154.0 nm，III 为 155.8 nm）。值得注意的是，由于相邻层之间的直接连接，分层生长习性（KBBF最严重的缺点）在LBF中可以得到有效改善。因此，LBF晶体将成为有前途的高性能深紫外非线性光学材料。深入的机理探索有力地证明了富B策略可以有效增强DUV NLO晶体的SHG效应和双折射，满足了我们材料设计的初衷。
Exploring practical deep-ultraviolet (DUV) non-linear optical (NLO) materials is still urgently required and severely challenging. Starting from an ideal hexagonal (BO)(infinity) layered geometry, we adopted a boron-rich strategy to introduce a high proportion of second harmonic generation (SHG)-active B-O(F) groups to design potential DUV NLO materials. Five novel noncentrosymmetric 3D crystal structures based on the LiB2O3F (LBF) system were predicted by employing the evolutionary algorithm combined with the density functional theory method. Benefiting from the high proportion of B-O(F) active groups and the favorable arrangements, the polar LBF-I and III crystals exhibit optimal comprehensive performances and surpass notable KBe2BO3F2 (KBBF) in all metrics: the SHG coefficient d(11) is 0.88 pm/V for I (0.74 pm/V for III), being nearly 2 times that of KBBF (0.47 pm/V), and their wider band gaps together with larger birefringence lead to the shorter phase-matching wavelength (154.0 nm for I and 155.8 nm for III) compared to KBBF (161 nm). Significantly, the layering growth habit, the most serious drawback of KBBF, can be effectively improved in LBF owing to the direct connection between neighboring layers. Therefore, the LBF crystals would be promising high-performance DUV NLO materials. The in-depth mechanism explorations strongly demonstrate that the B-rich strategy is effective in enhancing the SHG effects and birefringence of DUV NLO crystals, meeting the original intention of our material design.