Here, one-step synthesis of Zn/ZnO hollow nanoparticles along with solid nanoparticles is reported using the laser ablation in liquid (LAL) technique. Laser radiation of the 1064 nm wavelength is emitted from a Q-switched Nd:YAG laser and is incident on a solid zinc target kept in a water medium. The as-obtained hollow and solid particles are characterized by transmission electron microscopy (TEM) and UV-visible absorption spectroscopy. Hollow nanoparticles are produced by the laser generated bubbles produced in water. The surface of a hollow nanoparticle is assembled from smaller solid nanoparticles. A strong laser-particle interaction is also observed when laser ablation is carried out for a longer time duration. Photoluminescence (PL) emission measurements at room temperature show that all samples exhibit PL emission in the UV-visible region. A reduction in size and an increase in concentration of the synthesized nanoparticles is observed with increasing laser ablation time.

Copper (Cu) nanoparticles of average sizes (radius in nm) varying between 1.7 and 6 nm have been prepared by 1,064 nm Nd:YAG laser ablation of solid copper target in water medium. The nanostructures of the samples have been characterized using high-resolution transmission electron microscopes (HRTEM). The UVvisible absorption spectra obtained with a UV-visible spectrophotometer show sharp absorptions in the ultraviolet region and visible region due to the interband transition and surface plasmon resonance (SPR) oscillations in Cu nanoparticles, respectively. The increase in the linewidth of the SPR absorption peaks with the reduction in particle sizes are observed due to the intrinsic size effects. The behaviour of the UV-visible spectra associated with the Cu nanoparticles is studied as a function of laser fluence and laser ablation time.

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Gold nanoparticles of average size varying between 1.1 and 3.3 nm are prepared by 1064 nm Nd:YAG laser ablation of solid gold target kept in ethylene glycol medium. The measured UV-Visible absorption spectra showed the presence of sharp absorption peaks in the UV and in the visible regions due to the interband transition and surface plasmon resonance (SPR) oscillations in Au nanoparticles, respectively. The increase in linewidth of the SPR peaks with the reduction in particle sizes is observed due to intrinsic size effects. The prepared samples exhibit photoluminescence (PL) emissions in the UV-Visible region peaked at ∼354 nm due to the recombination of electrons with holes from sp conduction band to d-band of Au. The peak PL intensity in the sample prepared with 60 minutes of laser ablation time is enhanced by a factor of ∼2.5 compared to that obtained in the sample prepared with a laser-ablation time duration of 15 minutes.