Organic small molecule solar cells with a homogeneously mixed copper phthalocyanine:: C60 active layer

An efficient organic solar cell with a vacuum codeposited donor-acceptor copper phthalocyanine (CuPc):C-60 mixed layer is described. A device with a structure of indium tin oxide/330 Angstrom CuPc:C-60(1:1)/100 A C-60/75 A 2,9-dimethyl-4,7-diphenyl-1,10-phenanthroline/Ag has a series resistance of only R-S=0.25 Omega cm(2), resulting in a current density of similar to1 A/cm(2) at a forward bias of +1 V, and a rectification ratio of 10(6) at +/-1 V. Under simulated solar illumination, the short circuit current density increases linearly with light intensity up to 2.4 suns. The maximum power conversion efficiency is eta(P)=(3.6+/-0.2)% at 0.3 suns (AM1.5G simulated solar spectrum) and eta(P)=(3.5+/-0.2)% at 1 sun. Although the fill factor decreases with increasing intensity, a power efficiency as high as eta(P)=(3.3+/-0.2)% is observed at 2.4 suns intensity. (C) 2004 American Institute of Physics.