Fully solution processed p-i-n organic solar cells with an industrial pigment - Quinacridone

We report solution processed organic solar cells with quinacridone (QA), an industrial pigment, as the electron donor. Applying simple spin casting and thermal annealing, trilayer devices with a pure donor (p) layer, a bulk heterojunction (i) layer, and a pure acceptor (n) layer have been fabricated. Tert-butoxycarbonyl quinacridone (t-BOC QA), a soluble yellow precursor of industrial red pigment of quinacridone, was synthesized by replacing the H atom of the NH group on QA with a t-BOC group. Uniform thin films were prepared by spin casting t-BOC QA solutions, which could be converted into insoluble thin films by thermal treatment to remove the solubilizing groups. This conversion allowed for the subsequent depositions of multiple layers without the use of orthogonal solvents. The p-i-n devices showed much higher device performance than their bilayer and simple bulk heterojunction counterparts, exhibiting power conversion efficiencies (PCEs) as high as 0.83%. (C) 2011 Elsevier B.V. All rights reserved.