Ag/PVP/PAN nanocomposites with triangular nanoprisms of silver synthesized by UV-induced polymerization: Morphology manipulation and optical properties tuning

Solid nanocomposite films of silver/polyvinylpyrrolidone/polyacrylonitrile were synthesized for the first time by means of UV-induced polymerization. Structural characterization carried out by transmission electron microscopy revealed the presence of triangular silver nanoprisms with an edge length of similar to 40 nm and a thickness of similar to 15 nm in addition to spherical nanoparticles. The nanoparticles shape evolution process during synthesis and storage has been monitored in detail by UV-VIS-NIR spectroscopy and plasma resonance bands depending on the shape of the silver nanoparticles have been identified. Unlike spherical nanoparticles, which absorb light at 420-450 nm, the triangular nanoprisms demonstrate a clear absorption in the red range of the spectrum. The optical spectra of the composite films with incorporated silver nanoprisms manifest an intense in-plane dipole plasmon resonance band at 585-650 nm, as well as a weak out-of-plane quadrupole resonance band at 340 nm.