ABSTRACT
This research is mainly studied morphology and optical properties of copper nanoparticles prepared by pulsed laser ablation in distilled water. Colloidal copper nanoparticles were prepared by pulsed Nd:YAG laser with the fundamental frequency at 1064 nm in distilled water. Size and optical properties of the nanoparticles were characterized by Transmission Electron Microscopy (TEM) and UV/visible spectroscopy, respectively. The copper particles were rather spherical and the mean particles size about 381 nm. Surface plasmon resonance peak at 650 nm. The color of the colloidal solution is light green. It was concluded that the ablation of copper target in distilled water is a physical and flexible method for synthesis of copper nanoparticles.
KEY WORDS: Laser ablation; Copper nanoparticles; Colloids; Surface plasmon resonance
1. Introduction
The various methods of synthesis have great influence on size and shape of nanoparticles: hence, many techniques such as microemulsion, reverse micelles and reduction of copper salts have been developed to prepare copper nanoparticles [1-2]. Pulsed laser ablation was extensively used for many applications in the synthesis of nanostructured materials, among which nanoparticles formation, alloying, dissociation, fragmentation and size control of the particles are important [3]. Copper nanoparticles in distilled water by the pulsed laser ablation of a copper target.was focused on size, shape, composition and optical properties [4].
2. Experimental Procedures
Copper nanoparticles were prepared by pulsed laser ablation of a copper target. The target was 0.1 mm thickness. and filled 3ml of distilled water in glass vessel. A pulsed Nd:YAG laser with the fundamental wavelength at 1064 nm, energy of 50 mJ/pulsed, pulse length 50 μs were used for the laser ablation. After ablation, the sample was measured absorbance spectra by the UV-vis spectroscopy. Shape and size of nanoparticles were characterized by transmission electron microscopy (JEOL, JEM 2010, operated at 200kV). The specimen for TEM experiments were prepared by depositing a drop of copper nanoparticles onto carbon-coated copper grids.
3. Results and Discussion
The shape and size of copper nanoparticles in distilled water was characterized by transmission electron microscopy (TEM). It was shown in Figure 1.
(a)
Figure 1 (a) Typical TEM image and
(b) the selected area electron diffraction patterns of copper nanoparticles prepared in distilled water.
Figure 1a illustrates a typical bright-field TEM image of copper nanoparticles which were synthesized in distilled water. It imparts that the size of the particles is between 339 and 423 nm. Figure 1b show the selected area electron diffraction patterns of copper nanoparticles which were prepared in distilled water. The pattern consists of four resolved concentric rings, measured of fcc Cu (111), (200), (220) and (311) planes. Absorbance spectra of copper nanoparticles in water were shown in Fig. 2. It is clearly seen, the wavelength of maximum absorbance is 650 nm, which is related to the surface plasmon resonance of copper nanoparticles in distilled water.
Figure 2. absorbance spectra of colloidal copper nanoparticles synthesis in distilled water
4. Conclusions
In this work, copper nanoparticles were synthesis by pulsed Nd:YAG laser with the fundamental frequency at 1064 nm of copper target in distilled water. Transmission electron microscopy was employed for characterization of the size and shape of the nanoparticles. In distilled water the particles are rather spherical and the diameter of the nanoparticles is 381 nm and exhibit absorbance that is centered around 650 nm. The color of the copper nanoparticles is light green.
5. Acknowledgement
The authors would like to thanks Thailand International Development Cooperation Agency (TICA) for financial support.
6. References
[1] Environment protection agency, “Nanotechnology white paper”, 2007 [online]. Available: http://es.epa.gov/ncer/nano/publications/whitepaper12022005.pdf.
[2] L. Guo, Z.H. Wu, K. Ibrahim, T. Liu., Research of non linear optical properties copper nanoparticles, Eur. Phys. J. D, Vol. 9, 1999. pp.591-594.
[3] P.D. Townsend, R. Brooks, D.E. Hole, Z. Wu., Luminescence from copper nanoparticles, Apply. Phys. B Vol. 73, 2001. pp. 345-353 (2001).
[4] R.M. Tilaki, A. Iraji Zad, S.M. Mahdavi., Size composition and optical properties of copper nanoparticles prepared by laser ablation in liquids, Apply. Phys. A 88, 2007. pp. 415-419.
