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

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≈1.01 eV) was synthesized by Stille coupling reaction, which absorbs the light from 330–1220 nm 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 0.83 mA/cm2, open current voltage of 0.35 V, and photocurrent spectra response from 330 to 1100 nm under AM 1.5 simulator (100 mW/cm2). [ABSTRACT FROM AUTHOR]