Photoelectrochemical properties of poly (3,4-ethylenedioxythiophene)

The photoelectrochemical properties of poly(3,4-ethylene dioxythiophene)/po ly(styrene sulfonate) in contact with an electrolytic solution containing a redox couple were studied using the theories for the semiconductor-electro lyte interface. When this polymer-electrolyte interface is illuminated with h nu > Eg (gap energy) it exhibits cathodic photocurrent typical of p-type semiconductors, and the flat band potential, density of majority carriers, and the depletion layer thickness can be determined. To complete the band energy diagram of this polymer-electrolyte interface we obtained the band g ap energy through the absorption and photocurrent spectra. The relatively l ow band gap energy (1.5 eV) and the photoeffects observed at the interface suggest its use as the absorbing material in photoelectrochemical cells.