The photoelectrical properties of the system ITO/poly(4,4"-dipenthoxy-3'-dodecyl-2,2':5',2"-terthiophene)/aluminium are strongly dependent on the electrochemical preparation parameters of the polymer. In particular the polymerization temperature has a significant influence on the photoelectronic characteristics of polymer. The best properties were attained with polymers prepared at higher temperatures (32-40 degreesC).