Broad spectral sensitization of organic photovoltaic heterojunction device by perylene and C60

The characteristics of heterojunction devices consisting of indium-tin-oxide (ITO)/poly(3-alkylthiophene) (PAT)/N,N-'-diphenyl glyoxaline-3, 4, 9, 10-perylene tetracarboxylic acid diacidamide (PV)/Al, ITO/PAT-PV/PV/Al, and ITO/PAT-PV-C-60/PV/Al, which are typical photoinduced rectifiers, are reported. The device under dark conditions is almost insulating; however, when exposed to light marked rectification and strong photoresponse over a broad spectral range covering near-infrared to visible and UV wavelengths are observed. The effect of PV and C-60 doping as well as annealing on spectral photoresponse and photoelectric conversion was investigated. The results show that the efficient photoinduced electron transfer from PAT to PV and C-60 occurs at the interface between the composite and junction. (C) 2000 American Institute of Physics. [S0021- 8979(00)04624-7].