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This work aims to serve as a comprehensive guide to properly characterize solid-contact ion-selective electrodes (SC-ISEs) for long-term use as they advance toward calibration-free sensors. The lack of well-defined SC-ISE performance criteria limits the ability to compare results and track progress in the field. Laser-induced graphene (LIG) is a rapid and scalable method that, by adjusting the CO2 laser parameters, can create LIG substrates with tunable surface properties, including wettability, surface chemistry, and morphology. Herein, we fabricate laser-induced graphene (LIG) solid-contact electrodes using different laser settings and subsequently convert them into ion-selective sensors using a potassium-selective membrane. We measure the aforementioned tunable surface properties and correlate them with resultant low-frequency capacitance and water layer formation in an effort to pinpoint their effects on the sensitivity (Nernstian response), reproducibility (E°' variation), and potential stability of the LIG-based SC-ISEs. More specifically, we demonstrate that the surface wettability of the LIG substrate, which can be tuned by controlling the lasing parameters, can be modified to exhibit hydrophobic (contact angle > 90°) and even highly hydrophobic surfaces (contact angle ≈ 130°) to help reduce sensor drift. Recommendations are also provided to ensure proper and robust characterization of SC-ISEs for long-term and continuous measurements. Ultimately, we believe that a comprehensive understanding of the correlation between LIG tunable surface properties and SC-ISE performance can be used to improve the electrochemical behavior and stability of SC-ISEs designed with a wide range of materials beyond LIG. [ABSTRACT FROM AUTHOR]

Laser scribing effectively reduces the energy loss of grain-oriented silicon steel in alternating and pulsating magnetic fields. This study focuses on the 27Q120 material, analyzes the macroscopic surface morphology and iron loss variations of grain-oriented silicon steel under the influence of two types of laser spots (circular spots without the application of a diffractive optical element (DOE) and rectangular spots formed by a DOE), laser power (600 W–2400 W), and scribing spacing (3.5 mm–7.5 mm) as process parameters. The relationship between magnetic domain width, stress, and iron loss was analyzed. The result shows that the iron loss improvement rates (β) achieved with circular and rectangular spot scribing were 16.054% and 17.116%, respectively. Corresponding magnetic domain widths were 0.17754 mm and 0.1636 mm, with hysteresis losses of 0.5114 W/kg and 0.5033 W/kg, respectively. Under the same laser power and scribing spacing, a lower energy density significantly reduced the damage to the surface macroscopic morphology by the laser, leading to improved iron loss. Furthermore, the iron loss of grain-oriented steel is positively correlated with the width of magnetic domains and negatively correlated with compressive stress.

Present study employes a picosecond laser (532 nm) for selective P1 laser scribing on the indium tin oxide (ITO) layer and subsequent fine‐tuning of P1 scribing conditions with machine learning (ML) techniques. Initially, the scribing is performed by varying different laser parameters and further evaluate them via an optical microscope and two probe resistivity measurements. The corresponding scribing width and sheet resistance data are used as input databases for ML analysis. The classification and regression tree (CART)‐based ML analysis revealed that median pulse energy <5.7 μJ insufficient to separate the adjacent scribing regions. While pulse energy >5.7 μJ, APL > 35%, LSO > 46%, and processing speed ≥1250 mm s−1 gives ≥16 μm of scribing width. Further, the decision tree (DT) analysis showed that pulse energy of ≥8.1 μJ, and LSO ≥ 37% are required for electrically isolated lines. The feature importance score suggests that laser fluence and pulse energy determined the scribing width, whereas electrical isolation strongly depends on LSO and processing speed. Finally, the ML achieved conditions experimentally validated and reassessed via scanning electron microscope, and atomic force microscopy aligns well with optical microscope measurements. [ABSTRACT FROM AUTHOR]

A novel, in situ, low-cost and facile method has been developed to fabricate flexible NO2 sensors capable of operating at ambient temperature, addressing the urgent need for monitoring this toxic gas. This technique involves the synthesis of highly porous structures, as well as the specific development of laser-induced graphene (LIG) and its heterostructures with SnO2, all through laser scribing. The morphology, phases, and compositions of the sensors were analyzed using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. The effects of SnO2 addition on structural and sensor properties were investigated. Gas-sensing measurements were conducted at room temperature with NO2 concentrations ranging from 50 to 10 ppm. LIG and LIG/SnO2 sensors exhibited distinct trends in response to NO2, and the gas-sensing mechanism was elucidated. Overall, this study demonstrates the feasibility of utilizing LIG and LIG/SnO2 heterostructures in gas-sensing applications at ambient temperatures, underscoring their broad potential across diverse fields. [ABSTRACT FROM AUTHOR]

Advanced manufacturing techniques offer tremendous potential in electronics, photonics, and biomedicine. Self‐assembly is a powerful strategy for creating three‐dimensional (3D) artificial structures, but existing thin film release techniques have limitations in the relatively complex processes. Herein, a localized laser scribing strategy is proposed to guide the self‐assembly of two‐dimensional thin films into 3D microstructures. It is revealed that laser‐induced heating and momentum can release thin films and roll them into various microstructures. Uniquely, this method allows accurate control of shapes, curvatures, orientations, and sizes for the fabricated rolls. This is a one‐step strategy with no pre‐patterning or post‐drying required. The proposed method represents a significant improvement over existing self‐assembly techniques and may enrich the thin film self‐assembly materials and applications. As proof of concept, the prepared gold micro‐rolls are demonstrated as implanted stents in porcine arteries with impressive flexibility. This study provides a new approach to creating 3D microstructures with simplicity and high repeatability and has significant implications for the future of advanced manufacturing, especially in emerging miniaturized applications, such as invasive robotics, minimized drug delivery, implanted batteries, and nanophotonics. [ABSTRACT FROM AUTHOR]

Flexible electronic products, with their characteristics of flexibility and wearability, have attracted significant attention and have become an important direction in the research and development of the electronics industry. Planar micro-supercapacitors (MSCs) with flexible composite electrodes can provide reliable energy support for these products, propelling their further development. The research employed a quick, effective, and environmentally friendly method of laser scribing to create shape-controllable flexible composite electrodes on composite films of Poly(3,4-ethylenedioxythiophene) and graphene oxide (PEDOT/GO), which were subsequently assembled into MSCs. An analysis of the composite electrode morphology, structure, and elemental distribution was conducted through the utilization of SEM, TEM, and XPS techniques. Following this, a comprehensive evaluation of the electrochemical performance of the flexible MSCs was carried out, which included cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and assessment of cyclic stability. The analysis of the CV results indicated that the MSCs achieved the areal capacitance of 5.78 mF/cm2 at 5 mV/s. After 5000 cycles at a current density of 0.05 mA/cm2, the capacitance retention rate was 85.4%. The high areal capacitance and strong cycle stability of MSCs highlight the potential of PEDOT/reduced graphene oxide (PEDOT/rGO) electrodes in electrode applications. [ABSTRACT FROM AUTHOR]

Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy.

A high‐throughput, single‐source laser scribing method exploiting a transparent conducting oxide (TCO) indirect liftoff mechanism is developed to produce serially interconnected perovskite solar modules. The TCO‐based indirect liftoff mechanism relies solely on laser absorption in the front transparent electrode material reducing thermal damage to the overlying layers and allowing for fast scribing speeds with low‐cost μs‐pulse duration fiber laser systems. Minimal resistive power losses are observed with the method compared to conventional ablative laser scribes, maintaining the power conversion efficiencies of small‐area devices (≈0.2 cm2) across significantly larger deposition areas (≈1 cm2). Demonstrating > 3 m s−1 processing speeds, TCO‐based liftoff provides the highest throughput laser scribing method for thin‐film photovoltaic devices produced on glass/TCO substrates, capable of processing large‐area perovskite solar modules at a manufacturing scale. [ABSTRACT FROM AUTHOR]

The pseudocapacitive performance of MnO2 is intrinsically determined by its electronic structure, especially the spin state. However, the correlation between the electrochemical behavior and the spin state of electrode materials remains ill‐defined, and efficient spin regulation strategies for MnO2 are thus lacking. Herein, the study reports laser thermal shock of electrochemically deposited MnO2 for efficient spin regulation. The combined use of theoretical calculation and experimental investigation indicates that the thermal shock induces oxygen vacancy in MnO2 to reduce spin polarization and delocalize electron distribution. As a result, the electrical conductivity largely increases and the Na+ adsorption is reasonably optimized. By lasering an integrated electrode for only 83 s, a 54% increase of the specific capacitance is observed. For the first time, the pseudocapacitive capability of MnO2 is revealed by in situ electron paramagnetic resonance where the enhanced redox pair is correlated with evolution of Mn2+ during charge/discharge. Moreover, the commercial‐level mass‐loaded electrode also offers a decent performance enhancement after laser treatment, indicating the great prospect of this technology for real applications. This work innovatively correlates the pseudocapacitive performance of MnO2 with its spin state and offers a new avenue to optimize the electrochemical capability through spin regulation. [ABSTRACT FROM AUTHOR]

Present study employes a picosecond laser (532 nm) for selective P1 laser scribing on the indium tin oxide (ITO) layer and subsequent fine‐tuning of P1 scribing conditions with machine learning (ML) techniques. Initially, the scribing is performed by varying different laser parameters and further evaluate them via an optical microscope and two probe resistivity measurements. The corresponding scribing width and sheet resistance data are used as input databases for ML analysis. The classification and regression tree (CART)‐based ML analysis revealed that median pulse energy 5.7 μJ, APL > 35%, LSO > 46%, and processing speed ≥1250 mm s−1 gives ≥16 μm of scribing width. Further, the decision tree (DT) analysis showed that pulse energy of ≥8.1 μJ, and LSO ≥ 37% are required for electrically isolated lines. The feature importance score suggests that laser fluence and pulse energy determined the scribing width, whereas electrical isolation strongly depends on LSO and processing speed. Finally, the ML achieved conditions experimentally validated and reassessed via scanning electron microscope, and atomic force microscopy aligns well with optical microscope measurements.

A simple and fast (<15 min), two‐step laser scribing of cardboard substrates is described as a method for fabricating carbon electrodes modified with metallic nanoparticles. The first scribing step patterned a cardboard substrate (promoting the formation of porous carbon electrodes). The second step was included to produce metallic nanoparticles via a chemical reduction process of cations from an aqueous solution. For these experiments, the effects of copper, silver, nickel, cobalt, zinc, and gold were evaluated considering their effect on the electrical properties and the composition of the carbon materials produced. These experiments revealed that, despite significant changes in resistance (from 138±7 Ω for plain electrodes to just 53±3 Ω for Au‐modified electrodes), only marginal changes were observed in the morphology or composition of the material produced (IG/ID ranged from 1.2±0.3 for the plain cardboard to 1.8±0.3 for the cobalt‐modified electrodes). To demonstrate the applicability of the proposed strategy, Au‐modified electrodes were assembled into electrochemical sensors and applied to measure the metabolic activity of live microorganisms in various commercial samples, requiring only 100 μL of sample and 10 min of incubation time. [ABSTRACT FROM AUTHOR]

This paper describes the design and the development of laser edge isolation (LEI) system for Si solar cells. It consists of a Q-switched 532 nm Nd:YVO4 laser source, an optical set up, a system motorized (X-Y) linear stages, a cell fixing system based on vacuum chuck, a camera to visualize the working zone and a He-Ne laser source for optical alignment. The command and control of the LEI system is ensured by a LabVIEW program and National Instruments (NI) devices. The designed system allows the positioning of the continuous isolation grooves very close to the edges leading to maximize the solar collection area and thus the efficiency. The proposed and developed approach consists to integrate a square shape unity file into the main program with a variable magnification factor, K. In order to demonstrate the operational and functional capabilities of the designed LEI system, series of experiments were conducted, scribing of continuous isolation grooves along four sides of multi crystalline Si solar cells with an area of 100 mm x 100 mm and a thickness of 320 µm to achieve electrical EI. It was shown that the grooves are well continuous and the measured values of continuous grooves lines width and depth are in the range of a typical groove dimensions. The voltage-current characteristics of the solar cells front side EI were analysed using a solar simulator. From our measurements result, we find that the best efficiency equal to 10.4 and the highest fill factor (FF) equal to 67 % ensure a satisfactory edge isolation (EI) of the solar cell. [ABSTRACT FROM AUTHOR]

Improvement of magnetic properties of electrical steel can be achieved by reduction the size of magnetic domains. The application of local stresses through laser scribing leads to reduced core losses. In order to determine the effect of laser refinement conditions of magnetic domains on the properties of the soft magnetic material, four samples with a thickness 0.23 mm were refined. The refinement of each sample was carried out using different line energies of the laser beam. Estimation of the magnetic domain size was performed using the Jeffries method, the magnetic viewer was used to reveal the domain structure. The measurement of the magnetic properties was performed at a frequency of 50 Hz and an induction of 1.5 T. The analyzed results presented in this work indicate impact of laser refining on magnetic properties of grain oriented electrical steel depending on used laser beam energy. [ABSTRACT FROM AUTHOR]

The conversion of metal-organic frameworks (MOFs) into advanced functional materials offers a promising route for producing unique nanomaterials. MOF-derived systems have the potential to overcome the drawbacks of MOFs, such as low electrical conductivity and poor structural stability, which have hindered their real-world applications in certain cases. In this study, laser scribing was used for pyrolysis of a Cu-based MOF ([Cu4{1,4-C6H4(COO)2}3(4,4′-bipy)2]n) to synthesize a Cu-CuO@C composite on the surface of a screen-printed electrode (SPE). Scanning electron microscopy, X-ray diffractometry, and Energy-dispersive X-ray spectroscopy were used for the investigation of the morphology and composition of the fabricated electrodes. The electrochemical properties of Cu-CuO@C/SPE were studied by cyclic voltammetry and differential pulse voltammetry. The proposed flexible electrochemical Cu-CuO@C/SPE sensor for the simultaneous detection of hydroquinone and catechol exhibited good sensitivity, broad linear range (1–500 μM), and low limits of detection (0.39 μM for HQ and 0.056 μM for CT). [ABSTRACT FROM AUTHOR]

This article presents a novel approach for evaluating laser scribing quality through cross-section profiles generated from a three-dimensional optical profiler. Existing methods for assessing scribing quality only consider the width and depth of a scribe profile. The proposed method uses a cubic spline model for cross-section profiles. Two quality characteristics are proposed to assess scribing accuracy and consistency. Accuracy is measured by the ratio of the actual laser-scribed area to the target area (RA), which reflects the deviation from the desired profile. The mean square error (MSE) is a measure of how close each scribed cross-section under the same scribing conditions is to the fitted cubic spline model. Over 1370 cross-section profiles were generated under 171 scribing conditions. Two response surface polynomial models for RA and MSE were built with 18 scribing conditions with acceptable scribing depth and RA values. Both RA and MSE were considered simultaneously via contour plots. A scatter plot of RA and MSE was then used for Pareto optimization. It was found that the cross-sectional profile of a laser scribe could be accurately represented by a cubic spline model. A multivariate nonlinear regression model for RA and MSE identified pulse energy and repetition rate as the two dominant laser parameters. A Pareto optimization analysis further established a Pareto front, where the best compromised solution could be found. [ABSTRACT FROM AUTHOR]

A novel, in situ, low-cost and facile method has been developed to fabricate flexible NO2 sensors capable of operating at ambient temperature, addressing the urgent need for monitoring this toxic gas. This technique involves the synthesis of highly porous structures, as well as the specific development of laser-induced graphene (LIG) and its heterostructures with SnO2, all through laser scribing. The morphology, phases, and compositions of the sensors were analyzed using scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy and Raman spectroscopy. The effects of SnO2 addition on structural and sensor properties were investigated. Gas-sensing measurements were conducted at room temperature with NO2 concentrations ranging from 50 to 10 ppm. LIG and LIG/SnO2 sensors exhibited distinct trends in response to NO2, and the gas-sensing mechanism was elucidated. Overall, this study demonstrates the feasibility of utilizing LIG and LIG/SnO2 heterostructures in gas-sensing applications at ambient temperatures, underscoring their broad potential across diverse fields.

Flexible electronic products, with their characteristics of flexibility and wearability, have attracted significant attention and have become an important direction in the research and development of the electronics industry. Planar micro-supercapacitors (MSCs) with flexible composite electrodes can provide reliable energy support for these products, propelling their further development. The research employed a quick, effective, and environmentally friendly method of laser scribing to create shape-controllable flexible composite electrodes on composite films of Poly(3,4-ethylenedioxythiophene) and graphene oxide (PEDOT/GO), which were subsequently assembled into MSCs. An analysis of the composite electrode morphology, structure, and elemental distribution was conducted through the utilization of SEM, TEM, and XPS techniques. Following this, a comprehensive evaluation of the electrochemical performance of the flexible MSCs was carried out, which included cyclic voltammetry (CV), galvanostatic charge/discharge (GCD), and assessment of cyclic stability. The analysis of the CV results indicated that the MSCs achieved the areal capacitance of 5.78 mF/cm2 at 5 mV/s. After 5000 cycles at a current density of 0.05 mA/cm2, the capacitance retention rate was 85.4%. The high areal capacitance and strong cycle stability of MSCs highlight the potential of PEDOT/reduced graphene oxide (PEDOT/rGO) electrodes in electrode applications.

The development of thin-film photovoltaics has emerged as a promising solution to the global energy crisis within the field of solar cell technology. However, transitioning from laboratory scale to large-area solar cells requires precise and high-quality scribes to achieve the required voltage and reduce ohmic losses. Laser scribing has shown great potential in preserving efficiency by minimizing the drop in geometrical fill factor, resistive losses, and shunt formation. However, due to the laser induced photothermal effects, various defects can initiate and impact the quality of scribed grooves and weaken the module's efficiency. In this regard, much research has been conducted to analyze the geometrical fill factor, surface integrity, and electrical performance of the laser scribes to reach higher power conversion efficiencies. This comprehensive review of laser scribing of photovoltaic solar thin films pivots on scribe quality and analyzes the critical factors and challenges affecting the efficiency and reliability of the scribing process. This review also covers the latest developments in using laser systems, parameters, and techniques for patterning various types of solar thin films to identify the optimized laser ablation condition. Furthermore, potential research directions for future investigations at improving the quality and performance of thin film laser scribing are suggested. [ABSTRACT FROM AUTHOR]

Ultrafast laser scribing provides a new microscale materials processing capability. Due to the processing speed and high-quality requirement in modern industrial applications, it is important to measure and monitor quality characteristics in real time during a scribing process. Although deep learning models have been successfully applied for quality monitoring of laser welding and laser based additive manufacturing, these models require a large sample for training and a time-consuming data labelling procedure for a new application such as the laser scribing process. This paper presents a study on image-based characterization of laser scribing quality using a deep transfer learning model for several quality characteristics such as debris, scribe width, and straightness of a scribe line. Images taken from the laser scribes on intrinsic Si wafers are examined. These images are labelled in a large and a small dataset, respectively. The large dataset includes 154 and small dataset includes 21 images. A novel transfer deep convolutional neural network (TDCNN) model is proposed to learn and assess scribe quality using the small dataset. The proposed TDCNN is able to overcome the data challenge by leveraging a convolutional neural network (CNN) model already trained for basic geometric features. Appropriate image processing techniques are provided to measure scribe width and line straightness as well as total scribe and debris area using classified images with 96 percent accuracy. Validating model's performance based on the small data set, the model trained with the large dataset has a similar accuracy of 97 percent. The trained TDCNN model was also applied to a different scribing application. With 10 additional images to retrain the model, the model accuracy performs as well as the original model at 96 percent. Based on the proposed TDCNN classification of debris on a scribed image of straight lines, two algorithms are proposed to compute scribe width and straightness. The results show that all the three quality characteristics of debris, scribe width, and scribe straightness can be effectively measured based on a much smaller set of images than regular CNN models would require. [ABSTRACT FROM AUTHOR]

Abstract Increasing both clean water and green energy demands for survival and development are the grand challenges of our age. Here, we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane (3D-GCM) with active metal nanoparticles (AMNs) loading for simultaneously obtaining the water purification and clean energy generation, via a “green” one-step laser scribing technology. The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs, which exhibits high permeated fluxes (over 100 L m−2 h−1) and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving (0.1 bar). After adsorption saturating, the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis, and restores the adsorption capacity well for the next time membrane separation. Most importantly, the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation. Moreover, the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation, realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation. This “green” precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well.

The interaction between nanosecond laser and glass is complicated, and defects such as micro-cracks and fractures are prone to be generated during laser scribing. Acoustic emission (AE) technique is applied in this paper to monitor laser scribing of float glass. Strong consistency between AE signals and width of laser ablation area is found. With laser power increasing from 11.2 to 26.9 W, root mean square (RMS) values increase from 0.160 to 0.634 V, and width of heat affected zone (HAZ) increase from 12.396 to 53.711 μ m . Correlation between AE signals and laser scribing quality is investigated by characteristic analysis. When scanning speed is kept constant (200 mm/s) and laser power is gradually increasing from 11.2 to 24.2 W, RMS values and MARSE are increasing (0.3–1.2 V, 600–1500 correspondingly), and scribing quality is declining continuously ( W C W G increase from 0 to 0.343). Time-frequency spectrum analysis by CWT could be applied in defects diagnosis. Three prominent frequency bands contents (150 ~ 180 kHz, 200 ~ 250 kHz, and 280 ~ 320 kHz) were generated during laser scribing process. Higher frequency bands contents (200 ~ 250 kHz, and 280 ~ 320 kHz) are demonstrated to reflect defects by analyzing distribution characteristic of frequency contents. Intensity of higher frequency compositions is vigorous (≥ 0.5) when there are defects, while less than 0.5 with no defects. [ABSTRACT FROM AUTHOR]

The conversion of metal-organic frameworks (MOFs) into advanced functional materials offers a promising route for producing unique nanomaterials. MOF-derived systems have the potential to overcome the drawbacks of MOFs, such as low electrical conductivity and poor structural stability, which have hindered their real-world applications in certain cases. In this study, laser scribing was used for pyrolysis of a Cu-based MOF ([Cu4{1,4-C6H4(COO)2}3(4,4′-bipy)2]n) to synthesize a Cu-CuO@C composite on the surface of a screen-printed electrode (SPE). Scanning electron microscopy, X-ray diffractometry, and Energy-dispersive X-ray spectroscopy were used for the investigation of the morphology and composition of the fabricated electrodes. The electrochemical properties of Cu-CuO@C/SPE were studied by cyclic voltammetry and differential pulse voltammetry. The proposed flexible electrochemical Cu-CuO@C/SPE sensor for the simultaneous detection of hydroquinone and catechol exhibited good sensitivity, broad linear range (1–500 μM), and low limits of detection (0.39 μM for HQ and 0.056 μM for CT).

Finding a promising material as an alternative resource to replace the consumption of fossil fuels is necessary as the depletion of fossil fuels is increasing annually. A novel approach was explored to produce graphene from natural renewable resources. In this work, a laser scribing technique was conducted to produce large-scale graphene from Empty Fruit Bunches (EFB) of oil palm lignin biopolymer by varying the laser power. The morphology, structure, and electrical conductivity of scribed graphene were investigated at different laser power. Herein, a porous form-like structure with multilayered graphene was obtained at a laser power of 75%. The crystallite size (La) of laser power 75% was 28.4nm which shows a higher degree of graphitization was formed as laser power rises. Furthermore, the resistance was lesser at 75% laser power compared to 50% laser power concluding that 75% laser power has better electrical conductivity than low laser power. Hence, lignin-based laser scribed graphene (LSG) can be a promising and sustainable green substrate material to be utilized in supercapacitor applications. [ABSTRACT FROM AUTHOR]

Highlights: A novel multifunctional three-dimensional graphene-metal frame film for the combination of water purification and hydrolysis hydrogen production, which has excellent purification efficiency and extremely low energy consumption. A “green” one-step laser scribing technology without any organic solvent in the whole preparation process. Metal nanoparticles as the active site can be loaded in a graphene film and wrapped by graphene, preventing undesirable aggregation and increasing catalytic active sites.Increasing both clean water and green energy demands for survival and development are the grand challenges of our age. Here, we successfully fabricate a novel multifunctional 3D graphene-based catalytic membrane (3D-GCM) with active metal nanoparticles (AMNs) loading for simultaneously obtaining the water purification and clean energy generation, via a “green” one-step laser scribing technology. The as-prepared 3D-GCM shows high porosity and uniform distribution with AMNs, which exhibits high permeated fluxes (over 100 L m−2 h−1) and versatile super-adsorption capacities for the removal of tricky organic pollutants from wastewater under ultra-low pressure-driving (0.1 bar). After adsorption saturating, the AMNs in 3D-GCM actuates the advanced oxidization process to self-clean the fouled membrane via the catalysis, and restores the adsorption capacity well for the next time membrane separation. Most importantly, the 3D-GCM with the welding of laser scribing overcomes the lateral shear force damaging during the long-term separation. Moreover, the 3D-GCM could emit plentiful of hot electrons from AMNs under light irradiation, realizing the membrane catalytic hydrolysis reactions for hydrogen energy generation. This “green” precision manufacturing with laser scribing technology provides a feasible technology to fabricate high-efficient and robust 3D-GCM microreactor in the tricky wastewater purification and sustainable clean energy production as well. [ABSTRACT FROM AUTHOR]

This article presents a novel approach for evaluating laser scribing quality through cross-section profiles generated from a three-dimensional optical profiler. Existing methods for assessing scribing quality only consider the width and depth of a scribe profile. The proposed method uses a cubic spline model for cross-section profiles. Two quality characteristics are proposed to assess scribing accuracy and consistency. Accuracy is measured by the ratio of the actual laser-scribed area to the target area (RA), which reflects the deviation from the desired profile. The mean square error (MSE) is a measure of how close each scribed cross-section under the same scribing conditions is to the fitted cubic spline model. Over 1370 cross-section profiles were generated under 171 scribing conditions. Two response surface polynomial models for RA and MSE were built with 18 scribing conditions with acceptable scribing depth and RA values. Both RA and MSE were considered simultaneously via contour plots. A scatter plot of RA and MSE was then used for Pareto optimization. It was found that the cross-sectional profile of a laser scribe could be accurately represented by a cubic spline model. A multivariate nonlinear regression model for RA and MSE identified pulse energy and repetition rate as the two dominant laser parameters. A Pareto optimization analysis further established a Pareto front, where the best compromised solution could be found.

Process online monitoring is a vital and integral part of high-speed laser scribing process in which speed and quality are paramount. In this study, a multi-sensory platform for real-time monitoring of the ultrafast pulsed laser engraving process has been developed. Four different sensors have been examined from various perspectives and the results have been analyzed and compared. The real-time monitoring system developed for this study consisted of IPG ytterbium pulsed fiber laser, scan head, illumination system, and four monitoring sensors, including a spectrometer, pyrometer, infrared (IR) camera, and high-speed camera. Various experiments were performed to evaluate the performance of the designed platform by applying each sensor to monitor a high-speed laser scribing process in real-time. The output of each sensor was analyzed by changing different laser and process parameters, such as laser power, focal position, beam speed, and pulse length. Strengths, weaknesses, and challenges of using each monitoring tool for the laser engraving process were discussed based on the obtained results.

The objective of this study was to develop a novel real-time monitoring and control method for ultra-fast laser scribing processes utilizing spectrometer. Adjustment of laser process parameters such as laser power with high precision in real-time is critical in the laser engraving process due to the premium quality and speed requirements of the process. An online monitoring system was established using the Ocean Optics spectrometer, IPG ytterbium pulsed laser, and PXIe-8880 industrial computer. An algorithm for real-time control of the laser scribing process was developed based on the monitoring outcomes using LabVIEWⓇ software. Experimental methods were performed to evaluate the reliability of the developed monitoring system and control algorithm. The sensitivity of the spectrometer was assessed by changing laser power, pulse length, and focal point position. A workpiece consisting of two different metals, including stainless steel SS304L and steel S355, was used to evaluate the performance of the developed algorithm when scribing moved from one material to another. Instant accurate setting of the laser power based on the variations in intensities of metals from 750 AU to 1400 AU validated the reliability of the algorithm.

Laser scribing is developing rapidly in industrial applications as a method of material processing, especially in areas that require high levels of precision. This technology provides functionality and efficiency improvements in the manufacturing of solar panels. Due to the premium quality and speed requirements of the laser scribing technology, monitoring of this process in real-time is critical in order to promptly detect defects in the manufacturing process. However, common monitoring systems have been developed for other laser processes, like laser welding, which are noticeably slower than the laser scribing process. The goal of this research was to investigate the possibility of using photodiodes for real-time monitoring of the laser scribing process for Copper Indium Gallium Selenide (CIGS) solar panels. Various monitoring setup configurations were designed, developed, and examined to determine the viable option for implementation as a defect detection platform. Using different photodiode positions, the intensity of the light and the photodiode induced voltage for diffuse and specular reflections were tested, and the practical pros and cons of applying each configuration were analyzed. The capability of the monitoring system to distinct the different layers of the scribed CIGS cell was also examined to assess the penetration depth of the scribe. In addition, by performing several experiments with different scribe thicknesses and analyzing oscilloscope measurements, the optimal placement of the photodiode for accurate tracing of the scribing path was determined and verified. Key aspects of development of such monitoring system for solar panel applications were identified through this research.

In highly porous carbon electrodes, a large fraction of pores can be inaccessible to the electrolyte, which translates into lower specific capacitances. This is accentuated at high current densities. To circumvent this, channels can be opened to enhance ionic diffusion. In this work, ionic channels were created using a pulsed laser. Nine sets of laser-scribing parameters (pulse fluence and spot spacing) were applied on two sets of carbon-based supercapacitor electrodes: K-bar hand-coated electrodes (“K”) and screen-printed electrodes (“SP”). Profilometry and scanning electron microscopy revealed that, before laser-scribing, the latter already had several holes and trenches, whilst the former were compact films. Electrochemical measurements in Na2SO4 indicate improvements in the rate capability of the laser-scribed SP electrodes, namely an up to 50% reduction of the rate at which energy density decreases as power densities increase. For laser-scribed K electrodes, the slope of the Ragone plot only decreased by ca. 20% in the best set of conditions. However, for both sets of electrodes, a negative trade-off is observed: laser processed electrodes seem to have a lower specific capacitance. This might be caused by the entrapment of debris in the laser-drilled holes, which could lead to the overestimation of the active mass. Moreover, X-ray Photoelectron Spectroscopy analysis suggests that this may also be explained by the decrease in the oxygen functionalities and by its impact on the electrodes’ wettability. On the other hand, for electrodes tested in an organic electrolyte (tetrabutylammonium perchlorate in acetonitrile), the specific capacitance at 2 A/g was up to 66% higher for laser-scribed electrodes and an energy density of 13 Wh/kg was achieved even at 2.8 kW/kg.

The development of thin-film photovoltaics has emerged as a promising solution to the global energy crisis within the field of solar cell technology. However, transitioning from laboratory scale to large-area solar cells requires precise and high-quality scribes to achieve the required voltage and reduce ohmic losses. Laser scribing has shown great potential in preserving efficiency by minimizing the drop in geometrical fill factor, resistive losses, and shunt formation. However, due to the laser induced photothermal effects, various defects can initiate and impact the quality of scribed grooves and weaken the module’s efficiency. In this regard, much research has been conducted to analyze the geometrical fill factor, surface integrity, and electrical performance of the laser scribes to reach higher power conversion efficiencies. This comprehensive review of laser scribing of photovoltaic solar thin films pivots on scribe quality and analyzes the critical factors and challenges affecting the efficiency and reliability of the scribing process. This review also covers the latest developments in using laser systems, parameters, and techniques for patterning various types of solar thin films to identify the optimized laser ablation condition. Furthermore, potential research directions for future investigations at improving the quality and performance of thin film laser scribing are suggested.

The ultraviolet nanosecond laser processing of microgrooves was conducted on A-, C-, and M-plane sapphire sheets along different crystal orientations. The influences of crystal orientation on the mechanical cleaving of sapphire sheets containing laser-processed microgrooves were investigated. Experimental results revealed that laser-induced cracks within the microgrooves, ablation threshold, and material removal rate of sapphire were closely related to crystal orientation. The removal energies of aluminum and oxygen ions per unit length along different crystal orientations were theoretically calculated; the difference in material removal rates along different crystal orientations was explained. Mechanical cleaving indicated that sapphire sheets could be separated along the A-M, C-A, C-M, and M-A orientations, whereas cleaving sapphire along A-C and M-C orientations was difficult. Moreover, the changes in the structure of laser-processed sapphire were also analyzed. [ABSTRACT FROM AUTHOR]

Here, we successfully synthesize polyaniline (PANI)-modified laser-scribed graphene (LSG) composite electrodes for high-performance microsupercapacitors (MSCs). The three-dimensional (3D) porous LSG is directly patterned on a transparent polyethersulfone (PES) film via one-step laser irradiation. PANI is then electrodeposited on the LSG conductive skeletons to obtain LSG/PANI hybrid electrodes. As expected, the fabricated LSG/PANI-40 based MSC offers an outstanding areal capacitance of 129.51 mF cm−2, which is far larger than that of pure LSG-based MSC (0.58 mF cm−2). Therefore, this study demonstrates the significant application potential of LSG/PANI composite electrodes in high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

Given the outstanding progress in research over the past decade, perovskite photovoltaics (PV) is about to step up from laboratory prototypes to commercial products. For this to happen, realizing scalable processes to allow the technology to transition from solar cells to modules is pivotal. This work presents all‐evaporated perovskite PV modules with all thin films coated by established vacuum deposition processes. A common 532‐nm nanosecond laser source is employed to realize all three interconnection lines of the solar modules. The resulting module interconnections exhibit low series resistance and a small total lateral extension down to 160 μm. In comparison with interconnection fabrication approaches utilizing multiple scribing tools, the process complexity is reduced while the obtained geometrical fill factor of 96% is comparable with established inorganic thin‐film PV technologies. The all‐evaporated perovskite minimodules demonstrate power conversion efficiencies of 18.0% and 16.6% on aperture areas of 4 and 51 cm2, respectively. Most importantly, the all‐evaporated minimodules exhibit only minimal upscaling losses as low as 3.1%rel per decade of upscaled area, at the same time being the most efficient perovskite PV minimodules based on an all‐evaporated layer stack sequence. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synchronous preparation of cobalt nanoparticles decorated graphene electrodes through laser scribing. • A novel approach to fabricate metal particles decorated LIG electrodes for flexible MSCs. • The optimized MSCs exhibit dramatically improved electrochemical performance. • The devices exhibit outstanding potential for practical applications. • DFT calculations theoretically illustrate the influence of cobalt decoration. Transition metal nanoparticles-graphene nanocomposites incorporate the advantages of graphene and metal nanoparticles, which arouse extensive attention. Here, we design a novel, facile and versatile method for in-situ synthesis of laser-induced porous graphene (LIG) decorated with cobalt particles (Co). The LIG/Co nanocomposites are fabricated through one-step laser direct scribing on a customized film composed of polyimide (PI) powder, polyvinyl alcohol (PVA), and cobalt chloride (CoCl 2 ·6H 2 O) precursors. Benefiting from the unique properties of Co nanoparticles embedded LIG, the obtained optimal in-plane micro-supercapacitors (IMSC) based on LIG/Co-1.5 possesses an excellent areal capacitance of 110.11 mF cm−2 and a superior energy density of 9.79 μWh cm−2, which are about 79 times that of pure LIG-based IMSCs. Simultaneously, the LIG/Co-1.5 MSCs also present good cycling stability, remarkable modular integration capability, and outstanding mechanical flexibility, showing potential for practical applications. Additionally, the density functional theory (DFT) calculations indicate that the decorating of cobalt particles elevates electron transfer. Moreover, the interaction between electrolyte and electrodes is also improved with the introduction of cobalt particles. Therefore, this strategy offers a new avenue for facile and large-scale manufacturing of various metallic atoms in-situ decorating in porous graphene. [ABSTRACT FROM AUTHOR]

In order to solve the problems of multiple process parameters, difficult control and high process requirements in laser first/second scribing of aerospace chemical milling thin-wall parts, a laser scribing depth model based on thermal energy balance was established, and the relationship between laser power and speed was established with scribing depth as a target. Using AC850 laser scribing maskant as coating material, the effects of laser power, scribing speed, laser frequency, forward angle and side slope angle on the scribing depth were studied by single factor experiment. Experimental results show that the theoretical model is in good agreement with experimental data. The laser scribing depth is positively proportional to the laser power and inversely proportional to the laser speed and has little relationship with the laser frequency. The predicted accuracy of the mathematical equations regarding the laser power density and scribing depth, calculated by the laser power, speed and scribing depths experimental data, are 88.53% and 90.79%. The laser scribing depth at a forward angle of 6° and a side slope angle of 7° is deeper compared with the vertical incident scribing depth, and the angle is also the recommended angle of laser scribing. Based on the simplified regression model, the laser scribing depth model can be directly used in the laser NC system to realize the adaptive adjustment and accurate control of laser energy according to the actual laser speed. [ABSTRACT FROM AUTHOR]

In this work, a facile growing laser-scribed graphene (LSG) process is successfully demonstrated, which can pattern in situ sulfur (S)-doped porous graphene electrodes on a flexible sodium lignosulfonate (SLS)-coated polyethersulfone (PES) film. The typical microsupercapacitors (MSCs) based on S-doped porous graphene deliver an ultrahigh areal capacitance of 55.4 mF cm−2, and have good long-term cycle stability with 85.2% capacitance retention after 10000 cycles. Moreover, these devices exhibit superb mechanical flexibility and outstanding modular integration capability. This novel fabrication approach can be extended to other heteroatom-doped electrode materials for application in high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

In recent times, there has been a great increase in the demand of flexible micro-supercapacitors for use in many commercial applications. Flexible capacitors have the potential to replace conventional batteries as they can provide competitive energy storage while being much smaller in size and having greater lifetime than average lithium-ion batteries. The most used design for in-plane flexible micro-supercapacitors is the interdigitated design. However, from findings of various recent studies, it is believed that the capacitance of in-plane EDLC micro-supercapacitors can further be improved by changing electrode designs. Different fractal designs have shown great promise to enhance the electrochemical performance of in-plane micro-supercapacitors by maximizing the active surface area and minimizing the energy lost during ion-transport. In this work, we successfully fabricate graphene-based, laser-scribed flexible micro-supercapacitors and study the effects of change in geometry parameters on total capacitance. Four different geometries for electrode were designed i.e., (1) interdigitated design, (2) fractal F1 (Hilbert) design, (3) fractal F2 (Peano) design, and (4) fractal F3 (Moore) design, and were patterned onto the thin layer of graphene oxide using laser scribing technique. Detailed analysis was presented for the change in capacitance using cyclic voltammetry, galvanic charge-discharge, electrochemical impedance spectroscopy and electrostatic simulation using COMSOL Multiphysics. It was found that fractal design micro-supercapacitors give better performance with higher capacitance and energy density values in comparison to conventional design interdigitated micro-supercapacitors. Among all, Fractal F3 design showed the highest capacitance and energy density value in comparison to other devices. It was found that there were two factors affecting the performance of devices, i.e., (1) a higher active surface area for fractal designs as compared to interdigitated designs with the same unit area, and (2) in addition to electric double layer capacitance, there was also electric field being generated on the edges of electrodes, defined as edging effect. Among both factors, the latter was the major enhancer of capacitance in the fractal design devices.

Flexible pressure sensors play a vital role in wearable devices, human physiological activity monitoring, smart robots and other fields. However, current flexible piezoresistive sensors typically have the disadvantages of complex preparation processes, inability to take into account sensitivity and pressure response range, and poor cycle stability. Herein, a novel flexible asymmetric pressure sensor has been proposed by adjusting sensing material and optimizing the structure of electrode. As a crucial piezoresistive material, MXene/reduced graphene oxide (MXene/rGO) nanocomposite with a layer by layer stacked structure is developed by an efficient and precise one-step laser scribing technology. Benefit from this designed layer by layer crosslinked structure, the proposed flexible MXene/rGO asymmetric pressure sensor exhibits excellent pressure-sensing performances, such as high sensitivity of 2.25 kPa−1 (0 – 200 Pa), low detection limit of about 2.5 Pa, fast responsive recovery, and long cycle durability. So that our flexible MXene/rGO asymmetric pressure sensor can detect subtle body physiological motions in real time, such as wrist pulse, vocal vibration, finger movement, and breath. Additionally, the as-prepared sensor array integrated by $4\times 4$ identical MXene/rGO asymmetric pressure sensors exhibits good multi-touch function. Therefore, such conspicuous sensing performances endow our MXene/rGO asymmetric pressure sensor for widespread practical applications in future flexible wearable electronics. [ABSTRACT FROM AUTHOR]

Improving the performance of electrical steels within the magnetic circuits is essential to save energy. The domain refinement through local surface treatment by laser is an effective technique to reduce the iron losses in grain-oriented iron silicon steels. To interpret the mechanism of this technique, we have quantitatively studied the impact of nanosecond pulse laser treatment on the magnetic properties of grain-oriented Fe(3%wt)Si sheets. We measured the total power loss and apparent permeability of the samples using a Single-Sheet Tester (SST). The laser treatment resulted in a loss reduction of up to 24% compared to the average power loss of standard samples at 50 Hz. At mid-induction levels, the reduction was also accompanied by an improvement in apparent permeability. A dynamic magnetic behavior law was used to identify a dynamic property A including information on density, surface area and wall mobility and another internal permeability property Λ representative of static field and magnetization characteristics. Lastly, we presented the behavior of these properties under different laser treatment. [ABSTRACT FROM AUTHOR]

Electric Double Layer Capacitor (EDLC) holds the highest share of commercial supercapacitor market. However, it has been proven that current Helmholtz, Gouy-Chapman and Stern models do not provide comprehensive explanation for energy storage mechanism in EDLC. In this work the effects of interdigitated EDLC design on capacitance of flexible laser scribed interdigitated microsupercapacitor (LSG-MSC) are studied. Three design parameters are tested, (1) current collector-electrode interaction, (2) electrode aperture, and (3) distance between parallel electrodes. Noticeable change was observed in the total capacitance upon change in LSG-MSC design which was analyzed in detail using cyclic voltammetry, electrochemical impedance spectroscopy and electrostatic simulation using COMSOL Multiphysics. It was found that in addition to electric double layer capacitance, an electric field was generated between electrodes and between electrode and current collector which led to small electrostatic capacitance between them. This electric field was also found to cause disturbance in double layer formation at the electrode thus causing change in the overall capacitance as the design parameters were varied.

In-plane microsupercapacitors (MSCs) hold great promise for microscale power source, due to the extremely high power density and ultra-long cycling life. However, the scalable fabrication of flexible MSCs with high energy density remains a major challenge. Here, we demonstrate the fabrication of vanadium carbide/reduced graphene oxide (V 8 C 7 /rGO) MSCs via laser scribing on ammonium metavanadate/graphene oxide (NH 4 VO 3 /GO) films, prepared by efficient continuous centrifugal casting method. More than 20 MSCs can be produced on a flexible substrate in 30 min, showing the potential for scalable fabrication. The laser-induced V 8 C 7 /rGO shows highly porous microstructure, where vanadium carbide nanoparticles are in-situ synthesized and uniformly decorated on graphene nanosheets. The well-defined architecture endows V 8 C 7 /rGO MSCs with excellent electrochemical performance. The areal capacitance of these devices can be as high as 49.5 mF cm−2, 11 times higher than that of rGO MSCs. The volumetric energy density and power density can be up to 3.4 mWh cm−3 and 401 mW cm−3, respectively, competitive with the commercially available energy storage devices and most reported MSCs. In addition, V 8 C 7 /rGO MSCs show excellent flexibility and integrability, as well as long cycling life, promising for practical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

The development of miniaturized energy storage components with high areal performance for emerging electronics depends on scalable fabrication techniques for thick electrodes and an in‐depth understanding of the intrinsic properties of materials. Based on the coprecipitation behavior of electrically exfoliated graphene and reduced graphene oxide–templated polyaniline (PANi) nanoflake, this work develops a simple, green, low‐cost, and scalable drop‐casted technique to easily fabricate uniform thick electrodes (up to 80 μm) on various substrates. Through using a direct laser writing process, planar microsupercapacitors can be readily attained. As‐fabricated flexible all‐solid‐state microsupercapacitors exhibit an ultrahigh areal capacitance of 172 mF cm−2 at 0.1 A cm−2 and excellent cycling stability of 91% capacitance retention over 2000 cycles at a high current density of 1.0 A cm−2. Furthermore, based on the electrochemical quartz crystal microbalance research result, the pseudocapacitance contribution is mostly provided by the adsorption/desorption of SO42− anions during the protonation process of PANi. This work offers a simple strategy toward superior‐performance micro‐sized energy devices and a new perspective to understand the origin of the capacitance of composites and heterostructures.

Laser scribing has been proposed as a fast and easy tool to reduce graphene oxide (GO) for a wide range of applications. Here, we investigate laser reduction of GO under a range of processing and material parameters, such as laser scan speed, number of laser passes, and material coverage. We use Raman spectroscopy for the characterization of the obtained materials. We demonstrate that laser scan speed is the most influential parameter, as a slower scan speed yields poor GO reduction. The number of laser passes is influential where the material coverage is higher, producing a significant improvement of GO reduction on a second pass. Material coverage is the least influential parameter, as it affects GO reduction only under restricted conditions. [ABSTRACT FROM AUTHOR]