Synthesis and properties of partially conjugated hyperbranched light‐emitting polymers

Via A₂ + B₄ and A₂ + B₃ [where A₂ is 1,4‐distyrylol‐2,5‐butoxybenzene, B₃ is 1,1,1‐tris‐(p‐tosyloxymethyl)‐propane, and B₄ is pentaerythritol tetra(methyl benzene sulfonate)] approaches, we synthesized two kinds of partially conjugated hyperbranched polymers, hyperbranched polymer with 3 arms (HP1) and hyperbranched polymer with 4 arms (HP2), which had rigid conjugated segments [oligo‐poly(phenylene vinylene)] and flexible, nonconjugated spacers arranged alternately through ether bonds in the skeleton. The conjugated segments were modified by pendant butoxy groups, which imparted the resulting polymers with excellent solubility in common organic solvents and excellent film‐forming abilities. Fourier transform infrared and nuclear magnetic resonance spectroscopy were used to identify the structure of the monomers and polymers. Thermal property investigations showed that two polymers both had good thermal stability with their decomposition temperatures in the range 396–405°C and high glass‐transition temperatures, which are of benefit to the fabrication of high‐performance light‐emitting devices. The photophysical properties were studied, and the relative photoluminescence quantum efficiencies of HP1 and HP2 in dilute chloroform solution amounted to 56.8 and 49.3%, respectively. A brief light‐emitting diode device with a configuration of indium tin oxide/HP1/Ca/Al was fabricated, and its electroluminescence performance was studied. The brightness of the device reached an optimistic maximum of 190 cd/m² at 8.2 V. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010