Increased Efficiencies of the Copolymers with Fluoro Groups in Vinylene Units

详细信息    查看全文

• 作者：Youngeup Jin ; Kwanghyun Kim ; Sung Heum Park ; Suhee Song ; Jaehong Kim ; Jaeyeon Jung ; Kwanghee Lee ; Hongsuk Suh
• 刊名：Macromolecules
• 出版年：2007
• 出版时间：September 18, 2007
• 年：2007
• 卷：40
• 期：19
• 页码：6799 - 6806
• 全文大小：469K
• 年卷期：v.40,no.19(September 18, 2007)
• ISSN：1520-5835

文摘

New electroluminescent copolymers with fluoro groups in the vinylene unit, poly(9,9-di-hexylfluorene-2,7-vinylene-co-p-phenylenedifluorovinylene) (PFVPDFV), have been synthesized by the GILCHpolymerization. The fluoro groups were introduced on vinylene units to increase the electron affinities of thecopolymers. The PFVPDFVs exhibit absorption spectra with maximum peaks at 371-413 nm. The maximumabsorption peak at 413 nm of PFVPDFV1 was blue-shifted with a larger amount of the PDFV. In the PL spectraof PFVPDFVs, as the PDFV content increases up to 50% in the copolymer system, the fwhm was decreased by4-38 nm as compared to PFV. The HOMO energy levels of the copolymers were about 5.25-5.50 eV, and theLUMO energy levels were about 2.67-2.97 eV. The polymer LEDs (ITO/PEDOT/polymer/Al) of PFVPDFVsshowed emission with maximum peaks at around 472-538 nm. By adjusting the feed ratios of PDFV in thecopolymers, it was possible to tune the emission colors from greenish yellow to orange depending on the obtainedCIE coordinates. The luminescence efficiencies of the copolymers at room temperature are about 0.1-1.47 cd/A.PFVPDFV3 showed the maximum brightness of 4870 cd/m² and the highest luminescence efficiency of 1.47cd/A. The introduction of up to 50% of PDFV in PFVPDFVS can enhance the device performance to result inhigh current density, brightness, and efficiency due to the increased electron injection ability caused by the presenceof fluoro groups in the vinylene units.