Theoretical and experimental approach on dielectric properties of ZnO nanoparticles and polyurethane/ZnO nanocomposites J. Appl. Phys. 112, 054106 (2012); 10.1063/1.4749414 Carrier transport mechanisms of organic bistable devices fabricated utilizing colloidal ZnO quantum dotpolymethylmethacrylate polymer nanocomposites Appl. Phys. Lett. 97, 013304 (2010); 10.1063/1.3454774 High-density excitation effect on photoluminescence in ZnO nanoparticles Effect of annealing on the spectral and nonlinear optical characteristics of thin films of nano-ZnO J. Appl. Phys.

In this work we investigate the optical limiting property of polystyrene-zinc-oxide (ZnO) nanotop composite films, using an open aperture Z-scan technique. The nanocomposites are prepared for different loading concentrations of ZnO and are fabricated using spin and dip coating techniques. On exposing the films to a pulsed nanosecond laser at 532 nm, the nonlinear absorption (NLA) coefficient is found to be greater for spin-coated films compared to dip-coated films. The measured NLA coefficient is found to be enhanced with an increase in loading concentration of ZnO in the monomer for both spin- and dip-coated films.

We report an interesting switchover of optical nonlinearity from Reverse Saturable Absorption (RSA) to Saturable Absorption (SA) in polymer-Zinc Oxide (ZnO) nanotop composite films, investigated using the Z-scan technique. The nanocomposites have been prepared by in situ polymerization of the monomer in which ZnO nanotops are dispersed with the help of a dispersing agent. The films exhibit RSA for lower concentrations of ZnO nanotops, which changes to SA on increasing the loading concentration, irrespective of the monomer and dispersing agent used. These versatile films are good candidates for applications such as ultrafast optical switching and optical limiting.

No abstract

No abstract