Poly(N-vinyl-2-pyrrolidone) cluster-assembled nanostructured films prepared by low energy cluster beam deposition

Poly(N-vinyl-2-pyrrolidone) (PVP) cluster-assembled nanostructured films have been prepared by low energy cluster beam deposition method. TEM micrographs show that the films are assembled by spherical particles, which are distributed uniformly and randomly in the films. The pressure of helium carrier gas has a significant effect on the particle sizes and their distribution. Fourier transform infra-red and UV–Vis absorption spectra measurement have been performed so as to determine the structures and analyze the optical properties of the films. It is shown that the structural units of the nanoparticles of PVP cluster-assembled films are almost the same as that of original PVP. When compared to the original PVP casting film, PVP cluster-assembled film has 18 nm blue shift of maximum absorption and 0.67 eV blue shift of band gap.