Y Tamgadge, V Pahurkar, A Sunatkari, S Talwatkar… – Macromolecular Symposia, 2016
In this paper, we present synthesis of amino acids (l-arginine and l-alanine) assisted surface modification of ZnO nanoparticles (NPs) using chemical precipitation method. Study emphasizes the utility of l-arginine over l-alanine in the synthesis process and ZnO NPs with average particle size of 18 nm have been successfully obtained using l-arginine. Structural properties were evaluated using powder X-ray diffraction (XRD) pattern, energy dispersive X-ray spectroscopy (EDAX) and transmission electron microscopy (TEM) that confirmed the purity, surface morphology and hexagonal wurtzite crystal structure of ZnO NPs. Linear optical studies using ultraviolet-visible (UV-vis) spectroscopy and Fourier transform infra-red (FT-IR) spectroscopy indicated the blue shift of excitons absorption wavelength and surface modification by amino acids. Blue shifting is more prominent for l-arginine and optical band gap of 3.48 eV has been achieved in the present case. Third order nonlinearity (nonlinear refraction and absorption) of ZnO NPs embedded in polyvinyl alcohol (ZnO-PVA colloidal suspension) was studied by Z-scan technique at wavelength 632.8 nm in continuous wavelength regime which shows negative nonlinearity with self-defocusing effect. Large value of n2 and β were obtained in case of ZnO NPs passivated by l-arginine and effect was attributed to thermal lensing. Thermally stimulated third order nonlinear susceptibility (x(3)) for ZnO-PVA colloids have also been calculated and presented.
… UV-vis spectroscopy was performed using UV-visible spectrophotometer (BLK-C-SR, StellarNet, USA) in the wavelength range 280–900 nm. Fourier transform infra-red (FT-IR) spectra were recorded using IR double beam spectrophotometer, Shimadzu, Japan. …
