Post-polymerization modification of phosphorus containing conjugated copolymers. (July 2018)

• Record Type: Journal Article
• Authors: Cao, Hongda; Bauer, Nicole; Bi, Sheng; Li, Dawen; You, Wei; Rupar, Paul A.
• Is Part Of: European polymer journal. Volume 104(2018)
• Page Start: 157
• Page End: 163
• Publication Date: 2018-07
• Subjects: Heterofluorene -- Phosphafluorene -- Inorganic-element containing polymer -- D-A conjugated copolymers -- Polymer solar cells; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2018.05.009
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: A new phosphafluorene monomer was designed and, copolymerized with benzodithiophene to form the donor-acceptor conjugated polymer PPF-BDTT. Post-polymerization modification of PPF-BDTT with easily accessible methods such as reduction, thiolation, and metal coordination produced the phosphine sulfide polymer PPF-BDTT-S and phosphine gold chloride polymer PPF-BDTT-Au. These three polymers were characterized optically and electrochemically to investigate the structure-property relationship. Organic solar cells were also fabricated and demonstrated the potential abilities of phosphafluorene containing polymers in optoelectronics application. Highlights: A novel phosphafluorene and its donor-acceptor conjugated polymers were prepared. Direct post-polymerization modification of the phosphorus centers was investigated. Organic solar cells using phosphafluorene-based polymers were fabricated. Abstract: A new phosphafluorene (PF) based monomer, featuring a phosphine oxide substituted with a dodecyl chain, was synthesized. PF was copolymerized with benzodithiophene (BDTT) to form the copolymer PPF-BDTT which has a donor (BDTT)–acceptor (PF) structure. For the first time, direct post-polymerization modifications were performed on the phosphorus center of phosphafluorene-containing conjugated polymers. With Lawesson's Reagent, PPF-BDTT was transformed from a phosphine oxide to a phosphine sulfide. Reduction of the phosphine oxide of PPF-BDTT with HSiCl3, followed by reaction with AuCl∙SMe2, produced PPF-BDTT-Au, which contains AuCl coordinated to the phosphafluorene moiety. PPF-BDTT, PPF-BDTT-S, and PPF-BDTT-Au were characterized optically and electrochemically and the results compared to related BDTT containing copolymers. PPF-BDTT and its derivatives were found to have high LUMO and HOMO levels and larger bandgaps compared to common donor-acceptor copolymers. Organic solar cells were fabricated from PPF-BDTT, PPF-BDTT-S, and PPF-BDTT-Au, although the performances of these devices were poor with power conversion efficiencies ranging from 0.13% to 0.60%.