Low band-gap polymeric photovoltaic devices

摘要

We present results on photovoltaic devices based on novel thiophene-isothianaphthene copolymers (PDTI) with #pi#-#pi# band-gaps ranging from 1.2 eV to 1.8 eV. Single4ayer photovoltaic devices were fabricated from films of PDTI doped with a soluble fullerene derivative (6,6)-phenyl-C_(61)-butyric-acid-methyl-ester (PCBM) as the electron acceptor and Mended into poly(methyl methacrylate) to enhance the film quality. These devices exhibit spectral response extending into the infrared and are better matched to the solar spectrum as compared to standard PPV based ones. Such low band-gap materials also make possible the construction of dye-sensitized photovoltaic devices that take advantage of energy transfer from high energy absorbing dyes to the host polymer.