Random fluorene copolymers with on‐chain quinoxaline acceptor units |
| |
| Authors: | Argiri Tsami Xiao‐Hui Yang Frank Galbrecht Tony Farrell Hongbo Li Sylwia Adamczyk Ralf Heiderhoff Ludwig Josef Balk Dieter Neher Elisabeth Holder |
| |
| Institution: | 1. Bergische Universit?t Wuppertal, Fachbereich C ‐ Mathematik und Naturwissenschaften, Fachgebiet Makromolekulare Chemie und Institut für Polymertechnologie, Gau?strasse 20, D‐42097 Wuppertal, Germany;2. Universit?t Potsdam, Institut für Physik, Physik weicher Materie, Am Neuen Palais 10, D‐14469 Potsdam, Germany;3. Present address: General Electrics, Plasticslaan 1, PO Box 117, NL‐4600 AC Bergen op Zoom, The Netherlands;4. Fachbereich Elektrotechnik, Informationstechnik, Medientechnik, Lehrstuhl für Elektronik und Institut für Polymertechnologie, Bergische Universit?t Wuppertal, Rainer‐Grünter‐Strasse 21, D‐42119, Wuppertal, Germany;5. Bergische Universit?t Wuppertal, Fachbereich C ‐ Mathematik und Naturwissenschaften, Fachgebiet Funktionspolymere und Institut für Polymertechnologie, Gau?strasse 20, D‐42097 Wuppertal, Germany;6. Bergische Universit?t Wuppertal, Fachbereich C ‐ Mathematik und Naturwissenschaften, Fachgebiet Funktionspolymere und Institut für Polymertechnologie, Gau?strasse 20, D‐42097 Wuppertal, GermanyBergische Universit?t Wuppertal, Fachbereich C ‐ Mathematik und Naturwissenschaften, Fachgebiet Funktionspolymere und Institut für Polymertechnologie, Gau?strasse 20, D‐42097 Wuppertal, Germany |
| |
| Abstract: | Two series of novel random polyfluorene copolymers containing quinoxaline units were prepared by stressing the coupling according to Yamamoto. The first series contains 2,3‐bis‐(4′‐tert‐butyl‐biphenyl‐4‐yl)benzog]quinoxaline and the second series 2,3‐bis‐(4′‐tert‐butyl‐biphenyl‐4‐yl)quinoxaline as energy accepting unit. The copolymers were identified by gel permeation chromatography, infrared spectroscopy, and nuclear magnetic resonance spectroscopy. Thermal properties were analyzed by thermal gravimetric analysis and differential scanning calorimetry revealing amorphous copolymers that are stable up to 430 °C. The morphology was investigated using atomic force microscopy. The optical properties in solutions and thin films were analyzed. Furthermore, the thin film electro‐optical properties were determined in monolayer polymer light‐emitting devices. Single layer devices were built with efficiencies ranging from 0.15 to 2.0 cd/A. For the random copolymers with 5 mol % benzog]quinoxazoline in the polyfluorene backbone some threefold efficiency enhancement from 1.1 to 3.0 cd/A was achieved by utilizing an ultra thin interlayer of poly(9,9‐di‐n‐octylfluorene‐2,7‐diyl)‐alt‐1,4‐phenylene‐(4‐sec‐butylphenylimino)‐1,4‐phenylene] between PEDOT:PSS and the emissive random copolymer layer. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 4773–4785, 2007 |
| |
| Keywords: | conjugated polymers devices energy transfer fluorene copolymers luminescence photophysics polymer light‐emitting diodes structure‐property relations UV‐vis spectroscopy |
|
|
