文摘
We present two D-蟺-A organic cationic core structures leading to highly efficient nonlinear optical (NLO) salts (E)-2-(4-(dimethylamino)styryl)-1,1,3-trimethyl-1H-benzo[e]indol-3-ium iodide (P鈥揃I) and (E)-2-(2-(5-(dimethylamino)thiophen-2-yl) vinyl)-1,1,3 -trimethyl-1H-benzo[e]indol-3-ium iodide (S鈥揃I). Single crystals of the above two materials were successfully obtained by the slow evaporation method. Two different polymorphic crystals of both P鈥揃I and S鈥揃I were obtained from different polar solvents. Kurtz powder tests revealed that the maximum second harmonic generation (SHG) efficiency of P鈥揃I with monoclinic space group P21 is 1.14 times the benchmark DAST(4-N,N-dimethylamino-4,-N,-methylstilbazolium tosylate). Bulk single crystals of P鈥揃I were obtained with size of up to 17.0 脳 6.0 脳 2.0 mm3 without using seed crystals. This demonstrates that this material exhibits great crystal growth ability along with a high second-order optical nonlinearity, making it a very attractive candidate for NLO applications such as electro-optics and THz-wave generation.
