The copolymer, poly(3-methylthiophene-co-3-octylthiophene), was electrochemically synthesized from a mixture of 3-methylthiophene and 3-octylthiophene. Once the best condition for the copolymer formation was obtained a solid-state photoelectrochemical cell (PEC) was constructed and studied. The PEC contains the photoactive material poly(3-methylthiophene-co-3-octylthiophene), poly(3MT-co-3OT), coated on indium doped tin oxide (ITO) coated glass, an amorphous poly(ethylene oxide), POMOE, an ion conducting polymer electrolyte complexed with I3-/I- redox couple and an electrochemically polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) coated on ITO-coated glass as a counter electrode. An open-circuit voltage of 165 mV and a short circuit current of 0.21 µA cm-2 were obtained with light illumination of approximately 100 mW cm-2. Incident monochromatic photon-to-current conversion efficiency (IPCE%) of 0.51 for front side (ITO/PEDOT) illumination and 0.15 for backside (ITO/poly(3MT-co-3OT)) illumination at wavelength of 460 nm were obtained. In addition, dependence of the short circuit current and open circuit voltage on light intensity and time of illumination were studied.
electrochemical copolymerization; solid-state photoelectrochemical cell; poly(3-methylthiophene-co-3-octylthiophene); amorphous poly(ethylene oxide); I3-/I- redox couple
