Production of metal and metal-alloy nanoparticles with high repetition rate ultrafast pulsed laser ablation in liquids
First Claim
1. A method of producing nanoparticle colloids, comprising:
- generating ultrashort pulsed laser beams at a pulse repetition rate greater than 100 kHz, each pulsed laser beam having a pulse with pulse energy less than about 10 μ
Joules, and a pulse duration up to about 10 picoseconds (ps);
irradiating a target with said pulsed laser beams, said target being disposed in liquid that is substantially transparent at a wavelength of said pulsed laser beams, said target being a source material for production of metal or metal-alloy nanoparticles that result from target material modification, wherein said liquid is substantially free of any stabilizing chemical agents; and
imparting relative motion between said pulsed laser beams and said target with at least movement of the pulsed laser beams to limit heat accumulation and to substantially avoid blocking of laser pulses by scattering and absorption from nanoparticle colloids that are formed in said liquid at said repetition rate,wherein at said repetition rate above 100 KHz a size distribution dominated by nanoparticles results from fragmentation of particles in the laser plume, and highly stable nanoparticle colloids are produced with said steps of generating, irradiating, and imparting, notwithstanding said liquid being substantially free of any stabilizing chemical agents.
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Abstract
Various embodiments include a method of producing chemically pure and stably dispersed metal and metal-alloy nanoparticle colloids with ultrafast pulsed laser ablation. A method comprises irradiating a metal or metal alloy target submerged in a liquid with ultrashort laser pulses at a high repetition rate, cooling a portion of the liquid that includes an irradiated region, and collecting nanoparticles produced with the laser irradiation and liquid cooling. The method may be implemented with a high repetition rate ultrafast pulsed laser source, an optical system for focusing and moving the pulsed laser beams, a metal or metal alloy target submerged in a liquid, and a liquid circulating system to cool the laser focal volume and collect the nanoparticle products. By controlling various laser parameters, and with optional liquid flow movement, the method provides stable colloids of dispersed metal and metal-alloy nanoparticles. In various embodiments additional stabilizing chemical agents are not required.
50 Citations
23 Claims
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1. A method of producing nanoparticle colloids, comprising:
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generating ultrashort pulsed laser beams at a pulse repetition rate greater than 100 kHz, each pulsed laser beam having a pulse with pulse energy less than about 10 μ
Joules, and a pulse duration up to about 10 picoseconds (ps);irradiating a target with said pulsed laser beams, said target being disposed in liquid that is substantially transparent at a wavelength of said pulsed laser beams, said target being a source material for production of metal or metal-alloy nanoparticles that result from target material modification, wherein said liquid is substantially free of any stabilizing chemical agents; and imparting relative motion between said pulsed laser beams and said target with at least movement of the pulsed laser beams to limit heat accumulation and to substantially avoid blocking of laser pulses by scattering and absorption from nanoparticle colloids that are formed in said liquid at said repetition rate, wherein at said repetition rate above 100 KHz a size distribution dominated by nanoparticles results from fragmentation of particles in the laser plume, and highly stable nanoparticle colloids are produced with said steps of generating, irradiating, and imparting, notwithstanding said liquid being substantially free of any stabilizing chemical agents. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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Specification