Synthesis and luminescence properties of light emitting polymers

Abstract

Poly(2-methoxy-5-trimethylsilyl-1,4-phenylenevinylene) PMTSPV, was prepared as thin films via the water-soluble precursor route, and its electrical and optical properties were studied. The conductivity values of drawn ($L/L_0=7$) and undrawn $F_eCl_3$-doped PMTSPV films were 0.5 and 0.1 S $cm^{-1}$, respectively. Threshold voltage of the device was about 4 V and the emission maximum was at about 560 nm with quantum efficiency of $2×10^{-4}$% photons per electron, which corresponds to yellow light emission. The X(3) for the PMTSPV film was investigated by using third-harmonic generation method at 1907 nm fundamental wavelength, and found to be $1.0×10^{-11}$ esu. We report on the investigation of electroluminescence (EL) for a dye-doped polymer. This doping system consists of main chain conjugated poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and highly fluorescent dye rubrene. Low operation voltage and high electroluminescence efficiency were obtained simultaneously in the molecularly doped system. We made EL cells having 10 times higher EL efficiency than that of undoped MEH-PPV diode at nearly the same turn-on voltage. Poly[2-(5-cyclohexylmethoxy-pentyloxy)-5-methoxy-1,4-phenylenevinylene] (PMCYHPV) was synthesized through dehydrohalogenation polymerization. This polymer showed good solubility in common organic solvents. The absorption and photoluminescence (PL) emission maxima of PMCYHPV were 497 nm and 590 nm, respectively. The measured relative EL quantum efficiency of PMCYHPV was about 6 times higher than that of MEH-PPV. We also compared the relative PL quantum efficiency of PMCYHPV and MEH-PPV, respectively. The PL quantum efficiency of PMCYHPV was 15 % higher than that of MEH-PPV.Poly[4,4``-octafluorobiphenyldioxy-alt-(1,4-phenylenevinylene)-(2-trimethylsilyl-1,4-phenylenevinylene) -(1,4-phenylene)] (PFSi) was synthesized and characterized to investigate thermal, optical, electric and xerographic properties. LED (light emitting ...