The all-solid-state electrochemical photovoltaic cell n-CdSe//high molecular weight (HMW) PEG-based copolymer (modified PEO)(12)-CsT/0.1 T-2//ITO was investigated. PEO is poly(ethylene oxide), CsT is 5-mercapto-1-methyltetrazole cesium salt, T-2 is di-5-(1-methyltetrazole) disulfide and ITO is indium tin oxide conducting glass. Electrodeposited polycrystalline CdSe electrodes were characterized using various techniques. X-ray diffraction data reveal growth of the hexagonal phase, whereas formation of the face-centered cubic structure is not excluded. Optical absorption studies demonstrate that CdSe possesses a direct bandgap energy of 1.75 eV. In the dark, the semiconductor/polymer electrolyte interface shows a rectifying behaviour typical of a non-ideal Schottky junction formed between a n-type semiconducting material and a metal or an electrolyte. Under white light illumination (A = 0.5 cm(2)) at an incident intensity of 100 mW cm(-2), the cell exhibits the following characteristics at 50 degrees C: short-circuit current density, i(sc) = 891 mu A cm(-2), open-circuit potential, V-oc = 0.52 V, fill factor, ff = 0.37 and cell energy conversion efficiency, eta = 0.17%. It was demonstrated that the n-CdSe/solid polymer electrolyte interface is not homogeneous.