Achieving Large Second Harmonic Generation Effects via Optimal Planar Alignment of Triangular Units |
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Authors: | Xin-Yu Li Qi Wei Chun-Li Hu Jie Pan Bing-Xuan Li Zhen-Zhen Xue Xiao-Yu Li Jin-Hua Li Jiang-Gao Mao Guo-Ming Wang |
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Affiliation: | 1. College of Chemistry and Chemical Engineering, Qingdao University, Qingdao, 266071 P. R. China;2. State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, 350002 P. R. China |
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Abstract: | Trigonal planar units with large polarizability anisotropy and high physicochemical stability are ideal structural units for exploring nonlinear optical (NLO) materials. Integrating the merits of two types of triangular-like moieties, a family of second-order NLO-active hybrid halides, MATX (X = Cl (1), Br ( 2 ), and I ( 3 )), are achieved. MATX crystallizes in a nonpolar space group of 2c but exhibits the optimal spatial arrangement and superior NLO performance. The low coordination planar trigonal AgX3 units enable segregation in layers of the three-winged propeller-like Me3TPA units. All of the layers are packed in a perfect parallel fashion, making the functional materials exhibit superior NLO performances, including the phase matchable behavior with strong SHG responses (6.2/ 1 , 6.5/ 2, and 7.6/ 3 times that of potassium dihydrogen phosphate), large birefringence (0.232/ 1 , 0.252/ 2 and 0.260/ 3 at 1064 nm), high laser damage threshold, wide transparent window, and easiness of crystal growth. The first-principles calculations reveal that the coexistence of strong linear and nonlinear optical properties are ascribed to the synergistic effect of the trigonal moieties. This study points out a useful path for the rational design of excellent NLO materials. |
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Keywords: | noncentrosymmetric nonlinear optics second harmonic generation structure–property relationship triangular units |
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