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Analysis of alloy and solar cells with double-pulse calibration-free laser-induced breakdown spectroscopy
摘要： We applied variant of calibration free laser induced Breakdown Spectroscopy (CF-LIBS) approach for the compositional analysis of standard Gd/Ge/Si alloy and solar cells. The double pulse laser induced plasma was produced on the sample surface and the emission spectra were recorded at optimized interpulse delay and energy ratio. The Plasma temperature, determined using Boltzmann plot, was used to determine the concentration of all species present in a sample. The results are compared with reference values as well as conventional CF-LIBS results, which show that conventional and variant CF-LIBS results are similar and in close agreement to reference values. It is worth mention that the variant CF-LIBS results, but the approach is simpler and faster. Therefore, this approach was applied to three unknown polycrystalline silicon solar cells, which yield Al, C, Ca, Fe, In, Ti, Sb and Sn in the parts per million (ppm). This approach can potentially be applied for real-time trace monitoring in manufacturing processes of photovoltaic devices where conversion e?ciency depends strongly on impurities’ concentration.
关键词： Alloy and solar cells,Double pulse LIBS,Laser induced plasmas,Quantitative elemental analysis,Calibration free LIBS,Plasma parameters
更新于2025-09-23 15:21:01
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Detection of Nutrition and Toxic Elements in Pakistani Pepper Powders Using Laser Induced Breakdown Spectroscopy
摘要： In the current paper, we applied laser induced breakdown spectroscopy (LIBS) to determine the elemental distribution of nutritional and trace heavy metals in pepper powders available in Pakistan using standard calibration curve laser induced breakdown spectroscopy (CC-LIBS) technique. The samples were found to contained elements like K, Ca, Mg, Na, Fe, Zn, Al, Pb, Cu, and Cr. Additionally, we also identified the atmospheric H-alpha line of hydrogen in the spectra which was used to estimate the electron number density. To achieve a highly sensitive LIBS system to determine nutritional and trace amounts of toxic metals in pepper powders and to achieve the best limit of detection, the LIBS system was optimized by studying the dependency of LIBS signal intensity on laser irradiance, variation in spacing between the focusing lens and target as well on the gate width. To justify the results of LIBS study, we also determined the concentration of alike (duplicate) peppers by digesting samples in appropriate solvents using a standard method like inductively coupled plasma-optical emission spectrometry (ICP-OES). The minimum detection limit was recognized for trace heavy metals from calibration curves. The results of LIBS displayed noteworthy conformity with those acquired from the ICP-OES analysis. Results of both the techniques clearly revealed that K was the most abundant element in all the peppers followed by Ca, Mg, Na, Fe, Al, Pb, Zn, Cu, and Cr. The relative accuracy of our LIBS system for different species as compared with ICP technique was in the range of 0.08–0.3 at 2.5 % error confidence. Conclusively, the present work demonstrated the suitability of LIBS technique due to its rapid, non destructive and eco-friendly approach for food security.
关键词： ICP-OES,detection of heavy metals,peppers analysis,laser induced breakdown spectroscopy,plasma parameters,Health impacts of toxic metals,laser applications
更新于2025-09-23 15:21:01
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Electron dynamics in low pressure capacitively coupled radio frequency discharges
摘要： In low temperature plasmas, the interaction of the electrons with the electric field is an important current research topic that is relevant for many applications. Particularly, in the low pressure regime ((cid:1)10 Pa), electrons can traverse a distance that may be comparable to the reactor dimensions without any collisions. This causes “nonlocal,” dynamics which results in a complicated space- and time-dependence and a strong anisotropy of the distribution function. Capacitively coupled radio frequency (CCRF) discharges, which operate in this regime, exhibit extremely complex electron dynamics. This is because the electrons interact with the space- and time-dependent electric field, which arises in the plasma boundary sheaths and oscillates at the applied radio frequency. In this tutorial paper, the fundamental physics of electron dynamics in a low pressure electropositive argon discharge is investigated by means of particle-in-cell/Monte Carlo collisions simulations. The interplay between the fundamental plasma parameters (densities, fields, currents, and temperatures) is explained by analysis (aided by animations) with respect to the spatial and temporal dynamics. Finally, the rendered picture provides an overview of how electrons gain and lose their energy in CCRF discharges.
关键词： low pressure,particle-in-cell/Monte Carlo collisions simulations,electron dynamics,plasma parameters,capacitively coupled radio frequency discharges
更新于2025-09-23 15:21:01
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Spectral Characterization of Collinear Double-Pulse Laser Induced Breakdown Spectroscopy (DP-LIBS) for the Analysis of the Chinese Traditional Medicine <i>Artemisia annua</i>
摘要： A collinear dual-pulse laser induced breakdown spectroscopy (DP-LIBS) method was employed to analyze Chinese traditional medicine Artemisia annua. The spectral intensities and signal-to-background ratios of magnesium (II) 279.54 nm, CN 388.29 nm, calcium (II) 393.37 nm, and iron (II) 404.27 nm were used to evaluate the optical emission characteristics of A. annua induced by DP-LIBS. The temporal evolution characteristics, inter-pulse time, and laser energy values were optimized. In particular, the electron density and the temperatures of the plasma were reported as functions of the delay time. The results showed that the DP-LIBS had stronger intensity and better accuracy compared to single-pulse (SP) LIBS. The enhancement factors obtained using DP-LIBS for Mg, CN, Ca, and Fe were 7.2, 8.9, 13.8, and 3.4, respectively. This study provides important information about A. annua.
关键词： signal enhancement,plasma parameters,double-pulse laser induced breakdown spectroscopy (DP-LIBS),Artemisia annua
更新于2025-09-23 15:21:01
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Evaluation of electron temperature and electron density of laser-ablated Zr plasma by Langmuir probe characterization and its correlation with surface modifications
摘要： The plasma parameters of laser-ablated Zirconium (Zr) using a Langmuir probe technique have been investigated by employing a Q-switched Nd:YAG laser (532 nm, 6 ns) at various irradiances ranging from 8.6 to 15.5 GW/cm2. All the measurements have been performed under an ultra-high vacuum condition while keeping the probe at a fixed distance of 4 mm from the target. By varying the biasing voltages from 1 to 75 V, the corresponding values of electric currents are measured by the probe on the oscilloscope. Laser-induced Zr plasma parameters such as electron temperature, electron number density, plasma potential, Debye length, and thermal velocity have been evaluated from I–V characteristic curves of Langmuir probe data. It is found that both the electron temperature and thermal velocity of Zr plasma reveal an increasing trend from 18 to 41 eV and 2.8 × 108 to 4.3 × 108 cm/s, respectively, with increasing laser irradiance which is attributed to more energy deposition and enhanced ablation rate. However, the electron number density of Zr plasma exhibits a non-significant increase from 6.5 × 1014 to 6.7 × 1014 cm?3 with increasing irradiance from 8.6 to 10.9 GW/cm2. A further increase in irradiance from 12 to 15.5 GW/cm2 causes a reduction in the number density of Zr plasma from 6.1 × 1014 to 5.6 × 1014 cm?3 which is attributed to the formation of thick sheath, ambipolar electric field, and laser-supported detonation waves (Shock front). Scanning electron microscope analysis has been performed to reveal the surface morphology of irradiated Zr. It reveals the formation of cracks, ridges, cones, and grains. It was observed at high irradiances the ridges are vanished, whereas cones and cracks are dominant features. By controlling plasma parameters, surface structuring of materials can be controlled, which has a vast range of applications in the industry and medicine.
关键词： electron temperature,Langmuir probe,laser-produced plasma,plasma parameters,Electron number density
更新于2025-09-23 15:19:57
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Quantitative analysis of saindha salt using laser induced breakdown spectroscopy and cross-validation with ICP-MS
摘要： Saindha salt is considered to be more advantageous than the other edible salts for the patients suffering from diabetes, blood pressure and kidney diseases. To explore the constituent elements of this salt, laser induced breakdown spectroscopy (LIBS) has been exploited for its qualitative and quantitative analysis. The third harmonic (355 nm) of a Q-switched Nd:YAG laser has been used to produce the saindha salt plasma and the time integrated optical emission spectra were registered using a set of six miniature spectrometers covering the spectral range of 230–805 nm. The spectroscopic analysis of the emission spectra predominately revealed numerous neutral or singly ionized emission lines of Ca, Mg, Na, K, Fe, Sr, Si, Li and Al. The laser produced plasma was characterized by calculating the electron temperature from the Boltzmann plots and the electron number density from the Stark broadened line profile as a function of laser irradiance and distance from the target sample. The relative concentration of the constituent elements was extracted by the integrated line intensities of the strongest spectral line of each element using the self-calibration-LIBS (SC-LIBS) and one-line calibration free-LIBS (OLCF-LIBS) methods. For cross-validation, the LIBS results have been compared with that obtained from the inductively coupled plasma-mass spectroscopy (ICP-MS) showing good agreement.
关键词： inductively coupled plasma-mass spectroscopy,saindha salt,elemental analysis,one-line calibration-free LIBS,self-calibration-LIBS,plasma parameters
更新于2025-09-19 17:13:59
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Determination of Major Inorganic Nutrients in Maize Tissues by Calibration-Free Laser Induced Breakdown Spectroscopy
摘要： The quality of the available food is the main issue in the developing countries and maize is one of the commonly used foodstuffs in these countries. Laser-induced breakdown spectroscopy (LIBS) was employed to characterize the presence of the major inorganic nutrients in the maize samples. Each of the samples was shown to contain following elements: K, Ca, Mg, Fe, Na, Si, Li, Sr, Ti, Al, and C while Cr was only detected in the seeds. The electron number density was evaluated by the use of the Stark broadened profile of calcium line and the plasma temperatures have been determined using the Boltzmann plot method. Calibration-free LIBS (CF-LIBS) has been used for the quantitative elemental analysis of the samples. The consistency of the concentrations determined by CF-LIBS was validated using inductively coupled plasma – optical emission spectroscopy (ICP-OES).
关键词： calibration-free laser–induced breakdown spectroscopy (CF-LIBS),Maize,Plasma parameters,inductively coupled plasma–optical emission spectroscopy (ICP-OES)
更新于2025-09-12 10:27:22
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Quantification of copper remediation in the Allium cepa L. leaves using electric field assisted laser induced breakdown spectroscopy
摘要： We present trace constituents of three plants of Onion (Allium Cepa L.), grown in the prepared soil containing varying concentration of copper under controlled environment to check its remediation capacity using Laser Induced Breakdown Spectroscopy (LIBS). The quantitative analysis of the samples was performed using Atomic Absorption Spectroscopy (AAS). The deduced concentration of copper was 0.05, 0.085 and 0.17 ppm for different leaves samples prepared with 10, 20 and 30 mg/L copper dose added in the germination soils through water. The limit of detection (LOD) of copper (Cu) in the samples has been improved to about 0.028 ppm using the electric field assisted LIBS technique.
关键词： Plasma parameters,Emission Spectroscopy,LOD,LIBS,Cu
更新于2025-09-12 10:27:22