Synthesis and Photovoltaic Properties of Fluorene-Based Copolymers with Thiophene Heterocycle on the Side Chain

Abstract:

High molecular weight, readily soluable copolymer was prepared from 9,9-di (2-thienyl-hexyl) fluorene (TF) 2,7-bis(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)-9,9-di octyl fluorene and narrow band gap comonomer 2,3-dimethyl- 5,8-(5-bromo)-dithien-2-yl-quinoxalines (DTQU) using pallad- ium catalyzed Suzuki coupling methods. To compare the copolymer to this without thiophene in the C9 side chain of fluorene, the copolymer from DOF and DTQU was synthesized. The electrochemical, optical and photovoltaic properties of the copolymers were studied. The absorption spectra of the copolymers measured in thin films display two absorption peaks. The power conversion efficiency achieved in the device configuration ITO/PEDT/FT- DTQU:PCBM (1:2)/Al is 0.85% with open-circuit voltage (Voc) 0.8V. Further improvement by manipulating polymer/electrode interface and further investigation of more polyfluorene copolymers with narrow band gap aryl-hetero cycle units on the side chain is in progress.

• Periodical: Advanced Materials Research (Volumes 383-390)
• Pages: 7677-7681
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.383-390.7677
• Online since: November 2011
• Authors: Qiong Hou, Xiang Hua Zeng, Xin Xu, Ting Guo, Hong Yu Zhen, Guo Long Li
• Keywords: Fluorene, Side Chain, Solar Cell, Thiophene

References

[1] S. Günes, H. Neugebauer, N.S. Sariciftci, Conjugated Polymer-Based Organic Solar Cells, Chem. Rew, Vol. 107, 2007, pp.1324-1338.

DOI: 10.1021/cr050149z

[2] Q.M. Zhou, Q. Hou, G. Yu, Y. Cao, Fluorene Based Low Band Gap Copolymers for High Performance Photovoltaic Devices , Appl. Phys. Lett, Vol. 84, 2004, pp.1653-1655.

DOI: 10.1063/1.1667614

[3] S. Hongsuk, Y. Jin, K. Jinwoo, L. Kwanghee, Syntheses and Properties of Electroluminescent Polyfluorene-Based Conjugated Polymers, Containing Oxadiazole and Carbazole Units as Pendants, for LEDs, Polymer, Vol. 46, 2005, pp.12158-12165.

DOI: 10.1016/j.polymer.2005.10.080

[4] C.Y. Chuang, P.I. Shih, C.F. Shu, Bright-White Light- Emitting Devices Based on a Single Polymer Exhibiting Simultaneous Blue, Green, and Red Emissions, Macromolecules, Vol. 40, 2007, pp.247-252.

DOI: 10.1021/ma062192+

[5] J. Liu, L. Chen, S.Y. Shao, F.S. Wang, Highly Efficient Red Electroluminescent Polymers with Dopant/Host System and Molecular Dispersion Feature: Polyfluorene as the Host and 2, 1, 3-benzothiadiazole Derivatives as the Red Dopant, J. Mater. Chem Vol. 18, 2008, pp.319-327.

DOI: 10.1039/b712562c

[6] M. Ranger, D. Rondeäu, M.L. Leclerc, New Well-Defined Poly(2, 7-fluorene) Derivatives: Photoluminescence and Base Doping, Macromolecules, Vol. 30, 1997, pp.7686-7691.

DOI: 10.1021/ma970920a

[7] C. Kitamura, S. Tanaka, Y. Yamashita, Design of Narrow- Bandgap Polymers. Syntheses and Properties of Monomers and Polymers Containing Aromatic-Donor and o-Quinoid- Acceptor Units, Chem. Mater, Vol. 8, 1996, pp.570-578.

DOI: 10.1021/cm950467m

[8] M.S. Thomas, D.C. Liles, M. Landman, the Synthesis, Structural Features and Thermal Behaviour of Thiophene- Containing Dithiocarboxylate Complexes of Zinc(II), Polyhedron, Vol. 25, 2006, pp.3562-3568.

DOI: 10.1016/j.poly.2006.07.003

[9] C.J. Xia, R.C. Advincula, Decreased Aggregation Phenomena in Polyfluorenes by Introducing Carbazole Copolymer Units, Macromolecules, Vol. 34, 2001, pp.5854-5859.

DOI: 10.1021/ma002036h