Synthesis, electrical and optical properties of poly[2-(2-ethylhexyloxy)-1,4-phenylenevinylene] and poly [2-bromo-5(2-ethylhexyloxy)-1,4-phenylenevinylene]

Abstract

The branched monoalkoxy-substituted poly[2-(2-ethylhexyloxy)-1,4-phenylenevinylene] (EH-PPV) was prepared in thin films via the water-soluble precursor technique and solution elimination method. Poly[2-bromo-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (BEH-PPV) was also prepared via the water-soluble precursor technique and thermal elimination method. These polymers were characterized using UV-visible, FT-IR spectroscopy and DSC, TGA thermal analyzer. These precursor polymer films could be stretched up to 8 times, and the drawn films of the EH-PPV and BEH-PPV could be doped with $I_2$ and $FeCl_3$ to give conductivities of $10^{-1}\sim10^{-4}$S/cm. The third-order nonlinear optical susceptibility of the EH-PPV was determined by using third harmonic generation (THG) method at 1907 nm, fundamental wavelength. Measured $\chi^{(3)}$(-3$\omega$ ; $\omega$,$\omega$,$\omega$) value was $3.8\times10^{-12}$ esu. The maximum emission wavelength of EH-PPV film in photoluminescence spectrum was 560 nm and in the case of BEH-PPV 562 nm The color of PL spectra of two materials was yellowish-red.