[alpha],[alpha]'-Diarylacenaphtho[1,2-c]phosphole P-Oxides: Divergent Synthesis and Application to Cathode Buffer Layers in Organic Photovoltaics

• Published in: Chemistry, an Asian journal Vol. 7; no. 10; p. 2305
• Main Authors: Matano, Yoshihiro, Saito, Arihiro, Suzuki, Yuto, Miyajima, Tooru, Akiyama, Seiji, Otsubo, Saika, Nakamoto, Emi, Aramaki, Shinji, Imahori, Hiroshi
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley Subscription Services, Inc 01-10-2012
• Subjects: Chemistry
• ISSN: 1861-4728; 1861-471X
• DOI: 10.1002/asia.201200492

A divergent method for the synthesis of [alpha],[alpha]'-diarylacenaphtho[1,2-c]phosphole P-oxides has been established; [alpha],[alpha]'-dibromoacenaphtho[c]phosphole P-oxide, which was prepared through a TiII-mediated cyclization of 1,8-bis(trimethylsilylethynyl)naphthalene, underwent a Stille coupling with three different kinds of aryltributylstannanes to afford the [alpha],[alpha]'-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 [alpha]-aryl substituents. All the PO and PS 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-C70 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. [PUBLICATION ABSTRACT]