Influence of fullerenol dopant on light absorption by polyvinyl alcohol-based composite films
The study of the effect of fullerenol (С60 (ОН)44) dopant of different concentrations on the optical properties of polyvinyl alcohol (PVA) films has been presented. The addition of even a small concentration of fullerenol was found to lead to significant light absorption in the UV spectral range. As the concentration of fullerenol increased from 1 to 10 wt.%, the light transmission edge of the PVA: С60 (ОН)44 composite films shifted from 230 to 440 nm. The dependences of the extinction coefficient (EC) on the fullerenol concentration in the films were calculated for several wavelengths; these curves decreased with С60 (ОН)44 concentration increasing from 1 to 3 wt.%, but then EC values stopped decreasing. The light absorption in the studied samples was shown to cause by the fullerenol molecules' excitation during indirect HOMO → LUMO transitions. The Eg value estimated from their spectra, was 2.2±0.3 eV and depended little on the fullerenol concentration.