The ESR Study on Langmuir-Blodgett Films Layered with Ammontum-TCNQ Anion Radical Salts

Abstract Ammonium TCNQ anion radicals are formed with a TCNQ anion radical and an ammonium halide. Octadecylviologen-(TCNQ)2 shows a very interesting UV-visible spectrum in chloroform-acetonitrile mixture and in Langmuir-Blodgett films. The ESR characteristics of the N-docosylquinolinium-TCNQ films and octadecylviologen-(TCNQ)2 powder and films were studied to understand conducting mechanism and structure of LB films. The ESR spectra infer that the N-docosylquinolinium-TCNQ LB films exhibit anisotropic property. In other words, the LB films show angular dependence. Rotating the LB films around magnetic field results in a minimum band width at an angle close to the magic angle 54°. This results was due to the dipole-dipole interaction. The ESR spectra of octadecylviologen-(TCNQ)2 powders exhibit a narrow line at g=2 together with symmetrical structure of a triplet state arising from a dimeric species, genetic species. The LB films and powder do not show angular dependence. In the course of temperature incr...