Narrow Energy Gap Polymers with Absorptions up to 1 200 nm and their Photovoltaic Properties

• Published in: Macromolecular rapid communications. Vol. 29; no. 22; pp. 1804 - 1809
• Main Authors: Yi, Hunan, Johnson, Richard G., Iraqi, Ahmed, Mohamad, David, Royce, Richard, Lidzey, David G.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY‐VCH Verlag 19.11.2008
• Subjects: charge transport; conjugated polymers; fullerenes
• ISSN: 1022-1336; 1521-3927
• DOI: 10.1002/marc.200800440

A series of donor/acceptor carbazole copolymers comprising alternating 6,7‐diphenyl‐4,9‐bis‐(thiophen‐2‐yl)‐[1,2,5]thiadiazolo[3,4‐g]quinoxaline and 3,6‐dimethyl‐9‐alkyl‐9H‐carbazole repeat units (P1), or 3,6‐dimethyl‐9‐triarylamino‐9H‐carbazole repeat units (P2), or 9‐triarylamino‐9H‐carbazole repeat units (P3) has been prepared following Suzuki polymerization procedures. P3 absorbs light up to 1 200 nm and has an energy gap of 1.1 eV, while P1 and P2 have energy gaps of 1.3 and 1.25 eV, respectively. Photovoltaic cells with ITO/PEDOT:PSS/P3:PCBM (1:1 w/w)/Ca showed an open‐circuit voltage of 0.4 V under white light illumination, power conversion efficiency of 0.61%, and short‐circuit current of 5.2 mA · cm−2.