Polythiophene coated poly(methyl methacrylate) sheet as a new candidate for flexible organic electrode applications

Abstract

Poly(methylmethacrylate) (PMMA) is an amorphous, flexible and transparent polymer. We benefited these properties of PMMA to replace glass in solar cells. To replace rigid indium-tin oxide coated glass, PMMA sheet was coated by polythiophene. To achieve this goal, PMMA was in situ coated by FeCl3-catalyzed polymerization of thiophene in acetronitrile at room temperature. Different catalyst concentrations and reaction times were checked. The optimum catalyst concentration was found to be 1.8 g. Surface and cross-section morphologies of the coated layer were investigated using optical and scanning electron microscopes. At high catalysts concentration, a prolonged reaction time increased the polythiophene particles’ diameters, whereas at low catalyst concentrations longer reaction timeswere found to be almost of no effect on particles’ sizes. However, it was noted that the reaction time affects the thickness of the coated conductive layer on the substrate. The highest electrical conductivity was observed for a layer coated under optimized reaction conditions (that is, 1.8 g catalyst along with 20 min reaction time) with an electrical conductivity of 0.74 S/m and a conductive layer thickness of 37 micrometers. The prepared fully polymer electrode is supposed to replace ITO or FTO coated glasses in some applications such as solar windows.