New photoactive oligo- and poly-alkylthiophenes

• Published in: Polymer (Guilford) Vol. 49; no. 23; pp. 4942 - 4948
• Main Authors: Lanzi, Massimiliano, Paganin, Luisa, Caretti, Daniele
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 30.10.2008; Elsevier
• Subjects: Applied sciences; Conjugated polymers; Energy; Exact sciences and technology; Heterojunction polymer solar cells; Natural energy; Oligothiophene derivatives; Organic polymers; Photovoltaic conversion; Physicochemistry of polymers; Polymers with particular properties; Preparation, kinetics, thermodynamics, mechanism and catalysts; Solar cells. Photoelectrochemical cells; Solar energy; Oligothiophene derivatives; Conjugated polymers; Heterojunction polymer solar cells; Electrical conductivity; Short circuit currents; Electrical properties; Molecular structure; Thiophene copolymer; Experimental study; Oligomer; Fill factor; Open circuit voltage; Photovoltaic cell; Conjugated copolymer; Preparation; Aromatic copolymer; Oxidative polymerization; Thiophene derivative copolymer; Melting point
• ISSN: 0032-3861; 1873-2291
• DOI: 10.1016/j.polymer.2008.09.013

A new type of ω-methoxy-functionalized oligo-(OCT) and poly-(PQ) hexylthiophene characterized by a tetrameric repeating unit was synthesized and characterized. The configurational regularity and the mean degree of functionalization per thiophenic ring, lower than in commonly synthesized PATs, permitted the obtainment of more ordered chain conformations especially in the solid (film) state. Solar cells based on OCT and PQ films (as p-donor polymeric layer) mixed with Single-walled Carbon Nanotubes (SWCNTs, used as electron-acceptor system) were prepared and investigated. A power conversion efficiency of 0.52% with a fill factor of 0.42, an open-circuit voltage of 0.48V and a short-circuit current of 1.93mA/cm2 under 70mW/cm2 white light illumination is reported for the polymeric sample. The obtained performance is comparable with that of devices made with regioregular P3HT but the easiness of the monomer synthesis and polymer preparation, giving OCT and PQ with good yields, as well as the enhanced workability and filmability of the latters from diluted solutions of common organic solvents together with their low sensitivity to the environmental conditions (air oxygen, moisture, temperature) makes the synthesized materials very promising for the set-up of polymer photovoltaic cells. [Display omitted]