Fabrication of Cu nanoparticles by high-intensity femtosecond laser irradiation of solution

Takahiro Nakamura, Y. Herbani, Shunichi Sato

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

We have recently demonstrated a method for the preparation of gold [1], platinum [2], and gold-silver alloy nanoparticles [3] by high intensity laser irradiation of metallic salts solution. The formation of metal nanoparticles in the absence of any reducing agent can be attributed to the active species generated by high-intensity laser irradiation of water molecules (i.e., H 2O aq-, H·, OH ·, etc.). Solvated electrons (aq-) and hydrogen radicals (H-) are known to act as strong reducing agents in the solution. Accordingly, metal ions in the solution are readily reduced to rezo-valent metal. This technique enables us to produce metal nanoparticles with a narrow size distribution as well as small particle size down to single nanometer and is applicable to a large number of metal solutions. However, for a copper solution, Cu2+ ion has an absorption peak around 800 nm, which corresponds to the wavelength of a Ti:sapphire laser beam. Therefore, photo-induced reduction can hardly occur at the focal point because the laser beam is absorbed by the solution and then the laser intensity is attenuated before reaching the focal point. When ammonia is added to a solution of Cu 2+ ion, complex tetraammine copper (II) is formed and the absorption peak of Cu ion moves to 600 nm. (e.g., CuSO4 + 4NH3 [Cu(NH3)4]2+ + SO42). In this study, we fabricate Cu nanoparticles by high-intensity laser irradiation using tetraammine copper (II) ions as precursors. Complex ion solution was prepared by dissolving the copper (II) sulfate pentahydrate (CuSO 45H2O) in 1.0 wt% NH3 solution with the concentration of 0.05 wt%. 2-propanol ((CH3)2CHOH) was added to the solution as a scavenger of hydroxyl radical (OH.) to promote the reduction process. A quartz glass cuvette was filled with the solution of 3 ml. Femtosecond laser beam (wavelength: 800 nm; pulse energy: 5 mJ; pulse width: 100 fs; repetition rate: 100 Hz) was tightly focused in the solution by an aspheric lens (focal length: 8 mm; numerical aperture: 0.5). The laser intensity was estimated to be 2.11014 W/cm2. The irradiation time was 1 hour in the experiment.

Original languageEnglish
Title of host publication2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011
DOIs
Publication statusPublished - 2011 Sep 6
Event2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011 - Munich, Germany
Duration: 2011 May 222011 May 26

Publication series

Name2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011

Other

Other2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011
CountryGermany
CityMunich
Period11/5/2211/5/26

ASJC Scopus subject areas

  • Electrical and Electronic Engineering

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    Nakamura, T., Herbani, Y., & Sato, S. (2011). Fabrication of Cu nanoparticles by high-intensity femtosecond laser irradiation of solution. In 2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011 [5943342] (2011 Conference on Lasers and Electro-Optics Europe and 12th European Quantum Electronics Conference, CLEO EUROPE/EQEC 2011). https://doi.org/10.1109/CLEOE.2011.5943342