Acta Phys. -Chim. Sin. ›› 1993, Vol. 9 ›› Issue (05): 597-603.doi: 10.3866/PKU.WHXB19930506

• ARTICLE • Previous Articles     Next Articles

Spectroscopic Studies on Structure of Pyroelectric Langmuir-Blodgett Film

Wang Rong; Yang Jun; Dong Xi-Juan; Wang Hui; Tang Da-Xin; Jiang Lei; Li Tie-Jin; Zhang Bao-Wen   

  1. Institute of Atomic Molecular Physics, Chemistry Department, Jilin University, Changchun 130023; Institute of Photographic Chemistry Academia Sinica, Beijing 100101
  • Received:1992-03-20 Revised:1992-07-10 Published:1993-10-15
  • Contact: Yang Jun

Abstract: Azobenzene derivative (AD) was organized to form Z type polar films by Langmuir-Blodgett technique. The UV-VIS spectra show that the spectra of chloro-form solution exhibited a broad band with λ_(max) at 480 nm, corresponding to the mon-omer, while the spectra observed on AD film exhibited a sharp peak at 380 nm, corresponding to the absorption of the H-like aggregates. The 100 nm blue-shift of the absorption band from the monomer to the aggregates displays the existence of a high aggregate in the AD film. the linear dichroic FTIR spectra of AD film give informations on the molecular orientation of several main transition moments. The results show that the tilt angle of the axis of the hydrocarbon chain is 50° from the surface normal, and the tile angle of the azobenzene chromophore is 35°. The X-ray diffraction spectra display there are double long spacings of 3.5 nm and 3.1 nm respectively in the AD film. The further work of this system has been studied by temperature-changed UV-VIS spectra and infrared spectra.
According to the results mentioned above, the structure may play an important role in the high pyroelectric property owing to a contribution of the intermolecular additional dipole moments added to the spontaneous dipole moments.

Key words: LB film, Infrared spectra, UV-VIS spectra, Aggregation