Effect of anchoring groups on electrochemical self-assembly of ZnO/xanthene dye hybrid thin films.

Three xanthene dyes with different anchoring groups, eosin Y (EY), dicarboxy-eosin Y (CEY) and sulfonated eosin Y (SEY) were employed to electrodeposit ZnO/dye hybrid thin films to study the effect of anchoring groups on the electrochemical self-assembly (ESA) of hybrid thin films. The adsorption stabilities of the dyes in oxidized form were in the order, CEY >> EY > SEY, as evaluated by Langmuir isothermal adsorption experiments. The reduction potential of dyes, the dependence on Zn(2+) concentration that reflects stabilities of complexes between reduced dyes and Zn(2+) ion, and the diffusion coefficients of dyes were determined by electrochemical measurements.