Cyclopentadithiophene-benzothiadiazole oligomers and polymers; synthesis, characterisation, field-effect transistor and photovoltaic characteristics

Horie, M., Kettle, J., Yu, C.-Y., Majewski, L. A., Chang, S.-W., Kirkpatrick, J., Tuladhar, S. M., Nelson, J., Saunders, B. R. and Turner, M. L. (2012) Cyclopentadithiophene-benzothiadiazole oligomers and polymers; synthesis, characterisation, field-effect transistor and photovoltaic characteristics. Journal of Materials Chemistry, 22(2), pp. 381-389. (doi: 10.1039/C1JM12449H)

Abstract

Conjugated oligomers with various ratios of cyclopentadithiophene (CPDT) to benzothiadiazole (BT) repeating units are reported. These oligomers can be polymerised to high molecular weight polymers (Mn > 100k) by oxidative polymerisation using iron(III)chloride. The electronic properties of these materials were examined by cyclic voltammetry and UV-vis spectroscopy and the results compared to those calculated using density functional theory (DFT). Polymers with optimum ratios of CPDT : BT (2 : 1) units show hole mobilities in excess of 10−2 cm2 V−1 s−1 as the active layer in organic field effect transistors (OFETs). Bulk heterojunction organic photovoltaic (OPV) devices of these polymers with PCBM as the electron acceptor show a power conversion efficiency of 2.1% when processed in the absence of any additives. The reported OFET performance is significantly higher than the parent PCPDTBT alternating copolymer (CPDT : BT = 1 : 1) and also shows a moderate improvement in OPV performance.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Kettle, Professor Jeff
• Authors: Horie, M., Kettle, J., Yu, C.-Y., Majewski, L. A., Chang, S.-W., Kirkpatrick, J., Tuladhar, S. M., Nelson, J., Saunders, B. R., and Turner, M. L.
• College/School: College of Science and Engineering > School of Engineering > Electronics and Nanoscale Engineering
• Journal Name: Journal of Materials Chemistry
• Publisher: Royal Society of Chemistry
• ISSN: 0959-9428
• ISSN (Online): 1364-5501
• Published Online: 03 November 2011