Syntheses and nonlinear optical property of poly (2-methoxy-5-methylsulfinyl -1,4-phenylenevinyl-ene) (PMMSPV) and its copolymers

Abstract

Electron-donor and acceptor substituted Poly (2-methoxy-5-methylsulfinyl -1,4-phenylenevinylene) and its copolymers were synthesized through water soluble precursor route. These polymers were characterized with UV-visible, IR and thermogravimetric analysis (TGA). The conductivity of those polymers were measured with four-probe apparatus. The conductivities of $FeCl_3$-doped PMMSPV shows $1.4\times10^{-4}$ $Scm^{-1}$ and its copolymers with PPV ranged $10^{-4}\sim10^{-1}$ $Scm^{-1}$ according to the draw ratio and the copolymer composition. These results show that the electron-withdrawing groups, methylsulfinyl groups, raise the bandgap energy of PPV backbone. Photoluminescence of PMMSPV shows slightly blue-shifted emission maximum compared with that of PPV. The observed PL emission maximum at 520nm corresponds to the green light. Due to the possession of electronic dipole, the polymer was expected to show second order nonlinearity if optimal poling was performed. Second order nonlinear optical coefficient of the polymer was characterized with the second harmonic generation method. The measured $d_{33}$ value of PMMSPV was 1.5pm/V.