Fluorene-based conjugated poly(arylene ethynylene)s containing heteroaromatic bicycles: preparation and electro-optical properties
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A series of high molecular weight fluorene-based soluble poly(arylene ethynylene)s (PAEs) have been prepared and characterized. The polymers consist of 2,5-bis(3-tetradecylthiophen-2-yl)-3a,6a-dihydrothieno[3,2-b]thiophene, 2,5-bis(3-tetradecylthiophen-2-yl)-3a,6a-dihydrothiazolo[5,4-d]thiazole, or 4,7-bis(3-tetradecylthiophen-2-yl)benzo[c] [1, 2, 5] thiadiazole unit with an electron donor 9,9-bis(2-ethylhexyl)-9H-fluorene unit connected via electron accepting ethynylene linkage. The molecular weights (M w) of the polymers were found to be in the range of 103600–179000 g/mol with polydispersity index (PDI) of 3.9–5.0. Optical and redox properties have been investigated by UV–visible, fluorescence spectroscopy, and cyclic voltammetry (CV) measurements. Combination of experimental and density functional theory (DFT) calculations indicated that the benzothiadiazole unit incorporated polymer has lowest band gap with most stable lowest unoccupied molecular orbital (LUMO) energy level. Polymer light emitting diode properties have been investigated for the polymer having highest molecular weight with device configuration ITO/PEDOT:PSS/Polymer/LiF/Al. Well-behaved diode characteristics with EL maxima at 600 nm were observed.
KeywordsHigh Occupied Molecular Orbital Lower Unoccupied Molecular Orbital Lower Unoccupied Molecular Orbital Energy Benzothiadiazole Lower Unoccupied Molecular Orbital Energy Level
The authors thank M. N. Kamalasanan and R. Srivastava from NPL, New Delhi for their help in PLED device fabrication and characterization. The authors would also like to thank Professor Seungmoon Pyo, Konkuk University, Seoul, Republic of Korea and Professor Soonmin Jang, Sejong University, Seoul, Republic of Korea for their help in DFT calculations.
- 11.Krebs FC, Jørgensen M, Norrman K, Hagemann O, Alstrup J, Nielsen TD, Fyenbo J, Larsen K, Kristensen J (2009) A complete process for production of flexible large area polymer solar cells entirely using screen printing-first public demonstration. Sol Energy Mater Sol Cells 93:422–441CrossRefGoogle Scholar
- 12.Sandstorm A, Dam HF, Krebs FC, Edman L (2012) Ambient fabrication of flexible and large-area organic light-emitting devices using slot-die coating. Nat Commun 3:1002. doi: 10.1038/ncomms2002
- 13.Egbe DAM, Neugebauer H, Sariciftci NS (2011) Alkoxy-substituted poly(arylene-ethynylene)-alt-poly(arylene-vinylene)s: synthesis, electroluminescence and photovoltaic applications. J Mater Chem 21:1338–1349Google Scholar
- 25.Zheng H, Zheng Y, Liu N, Ai N, Wang Q, Wu S, Zhou J, Hu D, Yu S, Han S, Xu W, Luo C, Meng Y, Jiang Z, Chen Y, Li D, Huang F, Wang J, Peng J, Cao Y (2013) All-solution processed polymer light-emitting diode displays. Nature Commun 4:1971, doi: 10.1038/ncomms2971
- 32.Poul B, Kap-soo C, Gilles D, Nicolas D, Serge T, David PW, Li W (2011) Photovoltaic cell with benzodithiophene-containing polymer. WO/2011/085004Google Scholar
- 37.Zhan X, Liu Y, Yu G, Wu X, Zhu D, Sun R, Wang D, Epstein AJ (2001) Synthesis and electroluminescence of poly(aryleneethynylene)s based on fluorene containing hole-transport units. J Mater Chem 11:1606–1611Google Scholar
- 38.Mishra SP, Javier AE, Zhang R, Liu J, Belot JA, Osaka I, McCullough RD (2011) Mixed selenium-sulfur fused ring systems as building blocks for novel polymers used in field effect transistors. J Mater Chem 21:1551–1561Google Scholar