Structural and Optical Properties of New Poly vinyl Alcohol Grafted Methyl Red (PVA-g-MR)

Abstract

New polymeric dye films have been synthesised by condensation polymerization and reaction polyvinyl alcohol with methyl red dye to produce a new  graft copolymer (PVA-g-MR) .The structural properties of these samples were investigation by FTIR and XRD .The FTIR spectra  indicated the important functional groups for polymer and dye ,The peak at 1708cm^-1 related to carbonyl groups indicated  the correct reaction between PVA and dye. XRD investigation indicated  the crystalline  structure to new polymer .Optical parameters have been studied by preparing thin films on glass substrates using cast technique. Many optical  parameters have been calculated depending  on absorption and reflective  spectra  in the wavelength range (300-1000)nm , such as  refraction index   n(1.58) , absorption coefficient  α , optical energy gap E_g  (2.05eV), dielectric constant (2.52), Urbach tail (186meV)  and real and imaginary part of dielectric constant , Surface energy(SELF)  and volume energy loss(VELF) were also investigated by depending on real and imaginary parts of dielectric constant .It is clear that the value of  VELF greater than the peak of SELF ,it is also clear that  of SELF and VELF around  energy region 2.35eV and 2.5eV respectively. Optical ,electrical conductivities (σ_opt , σ_e ) were also investigate , σ_opt  increasing by increased the photon energy related to strong absorption .The results satisfied Wimple –Dideminco formula .Optical parameters of  (PVA-g-MR)   are useful to make the materials  a prominent one for  solar cell applications.