Photovoltaic properties of a single layer poly [3-(4-octylphenyl)-2,2′-bithiophene] (PTOPT)

A Schottky contact is made from a single layer polymer poly [3-(4-octylphenyl)-2,2'-bithiophene] (PTOPT) in its neutral state and a low work function metal (Al). The electrical and optical properties have been investigated by means of I-V measurements in the dark and under illumination. Various parameters such as the reverse saturation current density, barrier height, and diode quality factor were determined from the I-V curves in the dark of Al/PTOPT/ITO sandwich structure using thermionic emission theory. Spectral response of the device was measured at various wavelengths giving a peak at 500 nm. The IPCE% was obtained for illumination through both the Al and ITO sides. By illuminating the diode with a monochromatic light of wavelength 500 nm, the open-circuit voltage, short-circuit current density, power conversion efficiency, and fill-factor (FF) were obtained. The dependence of photocurrent on light intensity was also recorded and analyzed. (C) 2002 Elsevier Science B.V. All rights reserved.