1,720,965 research outputs found
Pulsed Laser Deposition of Carbon-Based Materials: A Focused Review of Methods and Results
No full textPulsed Laser Deposition (PLD) is a highly flexible experimental methodology for the growth of thin films of a broad variety of materials, based on the generation of laser-induced plasmas (LIP) with material ablated from a solid target and on the transfer of the ablated material to a substrate. This review is focused on carbon-based materials-specifically, diamond-like carbon (DLC), graphene and carbyne-and will both discuss the influence of the most critical experimental parameters on the obtained materials and present the experimental developments proposed in the recent literature to tailor the properties of the deposited films and optimize the standard PLD technique for production of various carbon-based materials
Editorial, LIBS 2022
No full textHeld in Bari (Italy) from September 5 through 9, 2022, LIBS 2022 was the twelfth international LIBS conference, and the first that took place in hybrid in-person/online mode after the SARS-CoV-2 pandemic forced the 2020 edition in 100% online mode. The conference was organized by the LIBS group of Bari (Italy), with Alessandro De Giacomo (University of Bari), Vincenzo Palleschi (CNR – ICCOM- Pisa) and Roberta Fantoni (ENEA-Rome) acting as General Chairs, supported by Program Chairs Marcella Dell’Aglio (CNR – NANOTEC-Bari), Antonio Santagata (CNR – ISM -Tito Scalo), Stefano Legnaioli (CNR – ICCOM- Pisa), and Violeta Lazic (ENEA- Rome)
Mechanisms and processes of pulsed laser ablation in liquids during nanoparticle production
Full text linkIn the last decade Pulsed Laser Ablation in Liquids (PLAL) has been widely investigated from the fundamental point of view, and various theories have been proposed. Although many important achievements have been obtained by the scientific community, many aspects still need to be clarified and many contradictions arise when comparing the interpretation of similar experiments carried out by different authors. In this paper we have reconsidered previous works focused on specific processes and stages of the PLAL, in order to outline a modern and comprehensive point of view of the overall physical aspects of PLAL. With this aim, several simultaneous diagnostic methods have been applied during the production of metallic nanoparticles (NPs), i.e. optical emission spectroscopy and fast imaging for the investigation of the laser-induced plasma, shadowgraph for the study of the cavitation bubble, and Double Pulse Laser Ablation in Liquid (DP-LAL) and laser scattering for the investigation of NPs location and mechanisms of release in solution. The connection between the various stages of the DP-LAL allows understanding the main characteristics of the produced NPs and the typical timescales of the basic mechanisms involved in PLAL
Plasma Parameters During Nanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy (NELIBS) in the Presence of Nanoparticle–Protein Conjugates
No full textNanoparticle-enhanced laser-induced breakdown spectroscopy (NELIBS) is an optical emission technique based on the laser-induced plasma (LIP) on a sample after the deposition of plasmonic nanoparticles (NPs) on its surface. The employment of the NPs allows an enhancement of the signal with respect to the one obtained with the conventional laser-induced breakdown spectroscopy (LIBS) enabling an extremely high sensitivity and very low limits of detection compared with the LIBS performance. Recently, NELIBS was used for monitoring the NP protein corona formation. As a matter of fact, the NPs in the presence of proteins adsorbed on the surface change their surface properties, therefore the sensing of protein corona formation was possible because of the strong dependence of NELIBS effects on the NP organization on the substrate, which in turn is deeply affected by the surface properties of the NPs. A correlation was found between NELIBS enhancement and the structure of the NP-protein conjugate in terms of protein content absorbed on the NP surface. An interesting question that was not yet exploited regards the role of LIP during the NELIBS when the NPs are covered with proteins. Since the presence of organic matter can strongly quench the LIP emission, the study of the LIP properties during protein corona sensing by NELIBS is of interest for two main reasons: (i) to understand whether the plasma parameters can vary in the presence of proteins adsorbed on the NP surface and (ii) to investigate how and if the plasma parameters themselves can influence the NELIBS processes. With this aim, the study of plasma parameters, i.e., electron densities and temperatures, during the sensing of NP protein corona by NELIBS is presented and discussed. The NPs used during these experiments were ultrapure gold NPs (AuNPs) produced by pulsed laser ablation in liquid, which are stable without any stabilizer. The human serum albumin protein is used to form AuNP-protein conjugates further deposited on a titanium target in NELIBS measurements. Dynamic light scattering, surface plasmon resonance spectroscopy, and laser Doppler electrophoresis for zeta-potential determination were employed to monitor the protein coverage of NP surface in the conjugate solutions before the NELIBS measurements
Perspective on the use of nanoparticles to improve LIBS analytical performance: nanoparticle enhanced laser induced breakdown spectroscopy (NELIBS)
No full textIn this paper, the new approach for Laser Induced Breakdown Spectroscopy (LIBS) based on nanoparticle
deposition on the sample surface is reviewed from both fundamental and application points of view. The
case of Nanoparticle-Enhanced LIBS (NELIBS) of metal samples is used for describing and discussing the
main causes of the emission signal enhancement. A set of test cases is presented, which shows
enhancements up to 1–2 orders of magnitude obtained using NELIBS with respect to LIBS. The feasibility
and potential of NELIBS are also discussed for several analytical applications, including analysis of
metallic samples, transparent samples and aqueous solution
An overall scientific investigation on pre and post Antoninian coins from Egnatia (Southern Italy)
No full textFeasibility of nanoparticle-enhanced LIBS (NELIBS) for the analysis of archaeological metallic artifacts: a critical assessment
No full textNanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy (NELIBS) is a LIBS variant that, in its original implementation, is based on intensifying the emission intensity of the sample under investigation by depositing nanoparticles on its surface. In this work, we evaluated the feasibility of this approach for the analysis of historical samples by carrying out NELIBS of a bronze archaeological object. Our purpose was exploiting the emission enhancement to perform single-shot analysis of ancient metallic samples and to improve the LOD (Limit Of Detection) of minor and trace elements while also reducing the sample damage. To this end, we carried out LIBS and NELIBS analysis of one bronze helmet fragment (VII century BCE), and we adopted two different analytical approaches i.e., calibration lines drawn with a set of copper-based standard alloys, and Calibration-Free (CF). When depositing NPs on the surface of the archaeological sample, some critical issues arose, which have the potential to limit the applicability of NELIBS to metallic samples with surfaces altered by corrosion and burial deposits, such as those of ancient artifacts. We discussed these issues and proposed experimental and analytical approaches to mitigate their detrimental effects on the analysis. Our results showed that the LOD decreased for all the elements analyzed in the standard alloys and in the archaeological sample, though not in the same extent, and confirmed that, while requiring some special care for experimental optimization and data analysis, NELIBS can be a powerful approach in heritage science studies
Fundamental study and analytical applications of nanoparticle-enhanced laser-induced breakdown spectroscopy (NELIBS) of metals, semiconductors and insulators
No full textNanoparticle-Enhanced Laser-Induced Breakdown Spectroscopy (NELIBS) is a recently proposed method to efficiently increase the LIBS emission signal of metals up to 2 orders of magnitude, by depositing metal nanoparticles (NPs) on the sample surface (De Giacomo A, Gaudiuso R, Koral C, Dell’Aglio M, De Pascale O Anal Chem 85). This considerable emission enhancement has been ascribed to two effects: (1) an improvement in the ablation effect, and (2) a more efficient production of seed electrons by field emission, in turn due to the enhancement of the laser electromagnetic field induced by the NPs themselves (De Giacomo A, Gaudiuso R, Koral C, Dell’Aglio M, De Pascale O Acta Part B, 98)
Reply to Comment on "nanoparticle Enhanced Laser-Induced Breakdown Spectroscopy for Microdrop Analysis at subppm Level"
Full text linkIn this paper, nanoparticle enhanced laser-induced breakdown spectroscopy (NELIBS) was applied to the elemental chemical analysis of microdrops of solutions with analyte concentration at subppm level. The effect on laser ablation of the strong local enhancement of the electromagnetic field allows enhancing the optical emission signal up to more than 1 order of magnitude, enabling LIBS to quantify ppb concentration and notably decreasing the limit of detection (LOD) of the technique. At optimized conditions, it was demonstrated that NELIBS can reach an absolute LOD of few picograms for Pb and 0.2 pg for Ag. The effect of field enhancement in NELIBS was tested on biological solutions such as protein solutions and human serum, in order to improve the sensitivity of LIBS with samples where the formation and excitation of the plasma are not as efficient as with metals. Even in these difficult cases, a significant improvement with respect to conventional LIBS was observed
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