Synthesis of New Conjugated Polyfluorene Derivatives Bearing Triphenylamine Moiety through a Vinylene Bridge and Their Stable Blue Electroluminescence

Citations Over TimeTop 1% of 2006 papers

Abstract

Two new conjugated polyfluorene derivatives bearing triphenylamine moiety through a vinylene bridge, PDPF and PBPF, have been successfully synthesized according to the Suzuki coupling method. The structures and properties of the monomers and the resulting conjugated polymers were characterized by using 1H NMR, 13C NMR, FT-IR, elemental analysis, GPC, TGA, DSC, UV−vis absorption spectroscopy, photoluminescence (PL) spectroscopy, and cyclic voltammetry (CV). The obtained polymers possess excellent solubility in common organic solvents, good thermal stability with 5% weight loss temperature of 415−448 °C, and relatively high glass transition temperature (Tg) at about 91−159 °C. The weight-average molecular weight (Mw) of PDPF and PBPF were 5.79 × 104 and 1.68 × 104 with the polydispersity index (PDI) of 2.75 and 2.69, respectively. The two-dimensional conjugated system of PFs can effectively suppress π-stacking/aggregation, improve hole injection, and facilitate intramolecular energy transfer. Single-layer PLED devices using PDPF and PBPF with the configuration of ITO/PEDOT:PSS/polymer/Ca/Al were fabricated. The maximum electroluminescence (EL) efficiency of the single-layer PLEDs based on PDPF and PBPF was about 0.19 and 0.51 cd/A, respectively. Meanwhile, the PLEDs with the optimized configuration of ITO/PEDOT:PSS/polymer/Alq3/Al showed greatly improved performance. The double-layer device based on PDPF emitted very stable greenish blue light with a low turn-on voltage of 3.6 V and showed the maximum luminance of about 2930 cd/m2 at 21.0 V. The maximum EL efficiency of the double-layer PLEDs based on PDPF and PBPF was both about 2.08 cd/A.

Related Papers

• → Polyfluorene Homopolymers: Conjugated Liquid-Crystalline Polymers for Bright Blue Emission and Polarized Electroluminescence(2001)830 cited
• → Synthesis and Characterization of Spiro-Triphenylamine Configured Polyfluorene Derivatives with Improved Hole Injection(2006)56 cited
• → Synthesis and tunable electrical behavior of polyfluorene functionalized with triphenylamine and (3-methyl-1-imidazolium-yl)hexyl side chains(2016)12 cited
• → Synthesis of polyfluorene-polytriarylamine block copolymers with light-emitting benzothiadiazole moieties: effect of chromophore location on electroluminescent properties(2017)5 cited
• Progress on the Optimization of Electroluminescent Properties for Polyfluorene Derivatives by Modification on its Molecular Structure(2006)