Metallic Copper Colloids by Reductive Laser Ablation of Nonmetallic Copper Precursor Suspensions

Abstract

Pulsed laser ablation in liquids (PLAL) has developed to a convenient and efficient method for the synthesis of colloidal solutions. So far, in most cases, the laser pulse is focused on bulk targets like metal plates. An interesting alternative is the use of suspended μm-sized precursors. This leads to higher production rates and simpler setups. A thorough understanding of the mechanism is essential in order to gain control over the characteristics of the synthesized nanoparticles. Therefore, we investigated the formation of copper colloids by PLAL of CuO, Cu3N, Cu(N3)2, and Cu2C2 powders in organic liquids. Thus, we can compare copper precursors based on elements of the 4th, 5th, and 6th main group. The chemical composition of the resulting nanoparticles is revealed by electron energy loss spectroscopy (EELS). The presented investigations point to a reductive ablation process followed by laser-driven aggregation and coalescence steps instead of a simple fragmentation mechanism.

Fragmentation mechanism of the generation of colloidal copper(i) iodide nanoparticles by pulsed laser irradiation in liquids

“…13 This suggests that the formation of the CuI particles does not follow the ablation, nucleation, and coalescence mechanism found for the other copper precursors. This is a crucial difference compared to the irradiation of other copper compounds like CuO, Cu 3 N, Cu(N 3 ) 2 and Cu 2 C 2 where the laser irradiation always leads to metallic copper nanoparticles.…”

“…13 In the case of CuI, the size of the nanoparticles follows a log-normal distribution. The ablation of CuO, Cu 3 N, Cu(N 3 ) 2 and Cu 2 C 2 precursors results in a bimodal Gaussian like size distribution.…”

“…9 Thus, for applications where additives are not tolerable, PLAL is the superior alternative. 13 In the first step a plasma is formed at the mm-sized precursor powder and thereby the copper atoms are ablated. It further simplifies the experimental set-up and even leads to new materials.…”

Perspective of Surfactant‐Free Colloidal Nanoparticles in Heterogeneous Catalysis

“…reviewed complementary techniques in order to adjust the average particle size of gold nanoparticles during pulsed laser ablation in liquid in a size regime ranging from 2 nm to 100 nm . According to Figure , the most important laser‐based size adjustment methods are summarized as follows: I) in situ size quenching by ion adsorption with sub‐micromolar concentration (Figure a), II) in situ size quenching by supports (Figure b), III) pulsed laser fragmentation in liquid (LFL) and reactive laser fragmentation in liquids (Figure c) . However, the authors rarely address the width of the NP distributions during their discussion.…”

Role of Dissolved and Molecular Oxygen on Cu and PtCu Alloy Particle Structure during Laser Ablation Synthesis in Liquids

“…[27,28,29] Several groups have workedo nt he laser ablationo fC ui n liquids and have shown different, interesting results.M üller et al synthesized Cu nanoparticles by using PLAL (l = 355 nm) in water and obtainedamixture of metallic Cu and CuO nanoparticles. Intensives tudies on laser-fragmented mm-sized Cu precursors (suspension), such as CuO, Cu 3 N, Cu(N 3 ) 2 ,and Cu 2 C 2 werecarriedout by Schaumberg et al [32] They reportedt hat small metallic Cu nanoparticles were formed in several organic liquids, even if an oxide was used as ap recursor.T hey have attributed this observation to fact that chemical reduction takes place duringt he formation of primary particles by an ucleation process. Tyurnuna et al have reportedt hat ablationo fC ui nH 2 Ob y using alaser with awavelength of l = 1064 nm led to spherical CuO nanoparticles.…”