Photocurrent response wavelength up to 1.1μm from photovoltaic cells based on narrow-band-gap conjugated polymer and fullerene derivative

Abstract
An extremely narrow-band-gap conjugated polymer poly(5,7-bis(4-decanyl-2-thienyl)thieno[3,4-b]diathiazole-thiophene-2,5) (PDDTT) (Eg≈1.01eV) was synthesized by Stille coupling reaction, which absorbs the light from 330–1220nm in solid thin film and shows good solution processibility. The polymeric photovoltaic cells based on PDDTT/[6,6]-phenyl-C61-butyric acid methyl ester blend show the short circuit density of 0.83mA∕cm2, open current voltage of 0.35V, and photocurrent spectra response from 330to1100nm under AM 1.5 simulator (100mW∕cm2).