ELECTROCHEMICAL STUDIES OF MOLECULAR ELECTROCHROMISM

Characteristics of newly developed electrochromic organic thin films prepared by the vacuum evaporation technique are described. ECDs (electrochromic displays) of the three primary colors (RGB) were obtained with 2,4,5,7-tetranitro-9-fluorenone (tetraNF) for red, 2,4,7-trinitro-9-fluorenylidene malononitrile (TNF-MN) for green and tetracyanoquinodimethane (TCNQ) for blue. Use of a co-evaporated film of TCNQ and tetrathiofulvalene (TTF)-TCNQ complex was found to increase the stability, because of the dispersion of TCNQ in the matrix of the TTF-TCNQ complexes, and the number of TCNQ molecules which take part in the redox reaction was also found to be greater in these films. By using polarized FT-IR and Raman spectroscopy, the structure and orientation of tetraNF and TNF-MN were found to be planar and oriented parallel to the electrode in both the oxidized and the reduced state, respectively. Moreover, the process for making a RGB matrix pattern by the vacuum evaporation technique is also described.