Photorefractive Performance of Hyperstructured Cyclotriphosphazene Molecular Glasses containing Carbazole Moieties


  • This work was supported by the National Natural Science Foundation of China through contract No.20274042, and by 2005HANCET-11 of Henan Province, P.R. China. The authors sincerely acknowledge Prof. Mingsheng Tang and Dr. Hongming Wang from Zhengzhou University, Prof. Jianguo Yu from Beijing Normal University, and Prof. Wenjian Liu from Peking University for their kind suggestions and great help in the computational analysis about the possible structure of the molecule M2.


Two hyperstructured photorefractive (PR) molecular glasses (M1 and M2) with a cyclotriphosphazene core are synthesized via nucleophilic substitution and an azo-coupling reaction. These molecules exhibit excellent solubility in common organic solvents and maintain a complete amorphous state in spite of their high glass-transition temperature. The nonlinear optical effects, two-beam coupling and four-wave mixing, respectively, are used to prove the PR performance in the optically transparent films of M1 and M2 doped with 30 % N-ethyl-carbazole. With no external electric field, a gain coefficient of 102 cm–1 and diffraction efficiency of 24 % are obtained in the composite made from M1, and an even higher gain coefficient of 214 cm–1 and diffraction efficiency of 31 % are obtained in the composite made from M2 owing to its higher chromophore loading.