title: α,α'-Diarylacenaphtho[1,2-c]phosphole P-oxides: divergent synthesis and application to cathode buffer layers in organic photovoltaics.
abstract: A divergent method for the synthesis of α,α'-diarylacenaphtho[1,2-c]phosphole P-oxides has been established; α,α'-dibromoacenaphtho[c]phosphole P-oxide, which was prepared through a Ti(II)-mediated cyclization of 1,8-bis(trimethylsilylethynyl)naphthalene, underwent a Stille coupling with three different kinds of aryltributylstannanes to afford the α,α'-diarylacenaphtho[c]phosphole P-oxides in moderate to good yields. X-ray crystallographic analyses and UV/Vis absorption/fluorescence measurements have revealed that the degree of π-conjugation, the packing motif, the electron-accepting ability, and the thermal stability of the acenaphtho[c]phosphole π-systems are finely tunable with the α-aryl substituents. All the P=O and P=S derivatives exhibited high stability in their electrochemically reduced state. To use this class of arene-fused phosphole π-systems as n-type semiconducting materials, we evaluated device performances of the bulk heterojunction organic photovoltaics (OPV) that consist of poly(3-hexylthiophene), an indene-C(70) bisadduct, and a cathode buffer layer. The insertion of the diarylacenaphtho[c]phosphole P-oxides as the buffer layer was found to improve the power conversion efficiency of the polymer-based OPV devices.
authors: Department of Molecular Engineering, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan. matano@scl.kyoto-u.ac.jp
authors: Yoshihiro
authors: Y
authors: Matano
authors: Arihiro
authors: A
authors: Saito
authors: Yuto
authors: Y
authors: Suzuki
authors: Tooru
authors: T
authors: Miyajima
authors: Seiji
authors: S
authors: Akiyama
authors: Saika
authors: S
authors: Otsubo
authors: Emi
authors: E
authors: Nakamoto
authors: Shinji
authors: S
authors: Aramaki
authors: Hiroshi
authors: H
authors: Imahori