Photovoltaic effect in Schottky junction of poly(3-alkylthiophene)/Al with various alkyl chain lengths and regioregularities

Photovoltaic effects of the Schottky junction cell consisting of indium tin oxide/poly(3-alkylthiophene) (PAT) films/Al have been studied as a function of alkyl chain length, regioregularity and film thickness. The photocurrents of the cell based on the excitation spectra with respect to their illumination sides were measured in order to elucidate the carrier generation mechanisms. It,vas found that the enhanced photocurrent is observed upon illumination of the At side for shorter alkyl side chain lengths and highly regioregular PAT. The results have been discussed through a model in which the carrier generation occurs predominantly at the depletion layer of the Schottky junction with a typical thickness of approximately 60 run.