title: Organic solid solution composed of two structurally similar porphyrins for organic solar cells.
abstract: A solid solution of a 75:25 mixture of tetrabenzoporphyrin (BP) and dichloroacenaphtho[q]tribenzo[b,g,l]porphyrin (CABP) forms when they are generated in a matrix of (dimethyl(o-anisyl)silylmethyl)(dimethylphenylsilylmethyl)[60]fullerene. This solid solution provides structural and optoelectronic properties entirely different from those of either pristine compounds or a mixture at other blending ratios. The use of this BP:CABP solid solution for organic solar cell (OSC) devices resulted in a power conversion efficiency (PCE) value higher by 16 and 300% than the PCE values obtained for the devices using the single donor BP and CABP, respectively, in a planar heterojunction architecture. This increase originates largely from the increase in short circuit current density, and hence by enhanced charge carrier separation at the donor/acceptor interface, which was probably caused by suitable energy level for the solid solution state, where electronic coupling between the two porphyrins occurred. The results suggest that physical and chemical modulation in solid solution is beneficial as an operationally simple method to enhance OSC performance.
authors.affiliation: Department of Chemistry, The University of Tokyo , 7-3-1 Hongo, Bunkyo-ku, Tokyo, 113-0033, Japan.
authors.forename: Yonggang
authors.initials: Y
authors.lastname: Zhen
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Tanaka
authors.forename: Koji
authors.initials: K
authors.lastname: Harano
authors.forename: Satoshi
authors.initials: S
authors.lastname: Okada
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Matsuo
authors.forename: Eiichi
authors.initials: E
authors.lastname: Nakamura