Electrochromic properties of phenantrene centered EDOT polymers

A series of phenantrene centered donor-acceptor type electroactive 3,4-ethlenedioxythiophene (EDOT) monomers (EP-X) containing N, S and Se heteroatom on the bezophenantra-X-diazole acceptor unit have been synthesized by Stille coupling reaction. These monomers were electrochemically polymerized by potentiodynamic method to obtain electrochromic polymer films. Spectro-electrochemical properties were also investigated by UV-vis absorption connected with the cyclic voltammetry measurements. The polymer films exhibited a remarkable trend of visible color (yellow, orange, red) at the neutral state due to changing the central acceptor moiety. These polymer films have multielectrochromic properties by means of moderately changing the absorbance/transmittance at the visible regime upon applied positive potentials. The donor-acceptor interaction at the neutral state correlated by DFT calculations was also supported by the interesting trend in the colors of these polymers. Finally, the electrochromic performance of EP-X polymer films represented a high redox stability, reasonable contrast ratio, coloration efficiency and response times.