Investigation on the structural and nonlinear optical properties of Pt doped TiO2 nanoparticles

Abstract

Pt doped TiO2 nanoparticles with different concentrations of Pt were prepared by sol–gel method. X-ray diffraction (XRD) study reveals that the samples have a homogeneous anatase phase tetragonal system and the lattice parameter analysis indicates that Pt ions substitute into the lattice of TiO2. The addition of dopant increases the growth of TiO2 grains, agglomerates them and shifts the absorption band of TiO2 from ultraviolet to visible region. The incorporation of Pt in TiO2 is also confirmed by fluorescence quenching and the fluorescence lifetime decreases as the volume fraction of Pt dopant increases. Open aperture Z-scan measurements done at 532nm using 7ns laser pulses show nonlinear absorption which arises from an effective two photon absorption process. The nonlinear optical properties are characterized by using fluence dependent transmittance measurements in order to reveal the optical limiting effects. It is found that the optical limiting performances of nanoparticles were greatly enhanced with increased concentration of Pt.