Compatibility of C60 grafted polystyrene/P3OT: Towards the extrusion of photoactive materials. (November 2017)

• Record Type: Journal Article
• Authors: Nourdine, Ali; Perrin, Lara; Carrot, Christian; Baer, Eric; Flandin, Lionel; Alberola, Nicole
• Is Part Of: European polymer journal. Volume 96(2017)
• Page Start: 1
• Page End: 9
• Publication Date: 2017-11
• Subjects: Fullerene-grafted polystyrene -- Poly(3-octylthiophene) -- Extrusion -- Rheological properties; Polymers -- Periodicals; Polymerization -- Periodicals; Polymères -- Périodiques; Polymérisation -- Périodiques; Polymerization; Polymers; Periodicals; Electronic journals; 547.705
• DOI: 10.1016/j.eurpolymj.2017.09.001
• Languages: English
• ISSNs: 0014-3057

Abstract

Graphical abstract: Highlights: For the first time, extrusion processing compatibility of electron donor (D) and electron acceptor (A) polymers was investigated to elaborate active layers based on D/A bulk heterojunction for organic photovoltaic OPV cells. Commercial poly(3-octylthiophene) (P3OT) and a series of synthesized polystyrenes grafted by various fullerene C60 contents (PSNC60 MS) were chosen as donor and acceptor polymers. The rheological behaviors of a series of C60 grafted PS were investigated in order to optimize the grafted C60 content for a viscosity close to that of the P3OT (at 180 °C) required for OPV active layers extrusion. Complex viscosity versus shear frequency behaviors (t 180 °C) displayed by P3OT and PSNC60 MS polymers are found to be superimposed for a C60 content of 12 vol%. D/A Bulk-heterojunction based on donor and acceptor polymers for photovoltaic application is processable via extrusion process. The extrusion preliminary tests are under progress at the moment. Abstract: To develop a new solventless and environment-friendly processing method for large-scale production of organic photovoltaic cells, the processability by extrusion of two photoactive polymers was studied. Poly(3-octylthiophene) was chosen as donor polymer and polystyrene grafted by fullerene C60 as acceptor polymer. In the molten state, poly(3-octylthiophene) exhibits a similar behavior to that of typical flexible polymers and then could be processed by extrusion at temperatures above 180 °C. An appropriate range of grafted C60 (from 4 to 12 vol%) has been determined in previous works from functional properties, thermal behavior and morphology observations displayed by a series of polystyrenes grafted by various fullerene C60 contents. The rheological properties (storage and loss moduli, melt viscosity) of the synthesized C60 grafted polystyrenes series are investigated. Two successive transitions in the viscosity are observed at 3–4 and 12–13 vol% of grafted C60, related to the percolation of C60 molecules and to the formation, growth and percolation of C60 aggregates, respectively. For extrusion compatibility with poly(3-octylthiophene), the optimal content of grafted C60 ranges from 7 to 12 vol% according to the rheological behavior. Thus, the processing of donor/acceptor heterojunctions by extrusion could now be considered to produce active layers of photovoltaic organic solar cells.