Optical Absorption of Polymer Films Doped with BEDT-TTF Polyiodides

Conducting reticulate doped polymeric films containing BEDT-TTF iodide crystalline network were annealed in order to transform the crystallites into crystal phases with metallic conductivity. Measured optical absorption spectra show that annealing shifts the absorption band to higher frequencies and increases the transparency of the films. This behavior corresponds to the transformation of the α-phase into the superconducting α$\text{}_{t}$-phase observed in (BEDT-TTF)$\text{}_{2}$I$\text{}_{3}$ single crystals.