Z-scan studies of Sn doped CuO nano-colloidal suspension

Abstract We report synthesis and characterization of l -valine capped Sn doped CuO nanoparticles (NPs). Pure and Sn doped CuO NPs were obtained by chemical co-precipitation method and were calcined at 500 °C for 2 h. X-ray diffraction (XRD) shows formation of crystalline CuO having monoclinic phase with average particle size of 8 nm. Utraviolet-visible (UV-vis) spectroscopy attests the formation of NPs and strong blue shift in the excitonic absorption has been observed for both uncalcined and calcined NPs. All samples show broad excitonic absorption in the wavelength range 351–654 nm due to inter band surface states transitions in CuO NPs. Fourier transform infra-red (FT-IR) spectroscopy confirms the role of l -valine as capping agent. Energy dispersive X-ray (EDX) spectroscopy confirms Sn doping into CuO. Transmission electron microscopy (TEM) attest the formation of CuO NPs having uniform near spherical shape. Third order NLO properties of undoped and Sn doped CuO NPs in the form of colloidal suspension have been investigated using Z-scan technique employing the fundamental wave at 1064 nm of a 7ns mode-locked Nd-YAG laser operating at 10 Hz. Sample with 5% Sn doping is found to possess strong nonlinear optical absorption and refraction due strong quantum confinement effect, TPA, ESA, etc. processess.