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Highly rapid direct laser fabrication of Ni micropatterns for enzyme-free sensing applications using deep eutectic solvent
Abstract
We carried out highly rapid laser-assisted deposition of conductive nickel microstructures on the surface of oxide glass from a deep eutectic solvent (DES). The implementation of deep eutectic solvents may significantly simplify the experimental procedure and drastically increase the deposition rate by more than 150 times in opposite to those observed for laser deposition from the aqueous solutions. It was shown that these structures exhibit promising electrocatalytic performance toward enzyme-free dopamine and acetaminophen sensing, including good sensitivity, low limit of detection and broad linear ranges.
... This approach effectively addresses critical challenges in electrochemical sensors, particularly in terms of reproducibility and reliability. Nickel nanoparticles synthesized by this method exhibit excellent electrocatalytic activity in the electrooxidation of dopamine-to-dopamine quinone [34] while providing a cost-effective alternative to noble metals. Furthermore, the incorporation of graphene into the composite system is expected to improve the overall performance of the synthesized electrode by exploiting the synergistic effects of different nanomaterials [35]. ...
... This approach effectively addresses critical challenges in electrochemical sensors, particularly in terms of reproducibility and reliability. Nickel nanoparticles synthesized by this method exhibit excellent electrocatalytic activity in the electrooxidation of dopamine-to-dopamine quinone [34] while providing a costeffective alternative to noble metals. Furthermore, the incorporation of graphene into the composite system is expected to improve the overall performance of the synthesized electrode by exploiting the synergistic effects of different nanomaterials [35]. ...
... The Nelder-Mead [34] method was used to optimize the laser fabrication process by systematically adjusting the synthesis parameters to achieve a high sensor response of the fabricated electrodes to the target analyte. The Nelder-Mead method works by maintaining a simplex-a geometric figure consisting of n + 1 vertices in an n-dimensional parameter space. ...
Deep eutectic solvents (DES) have emerged as versatile, sustainable media for the synthesis of nanomaterials due to their low toxicity, tunability, and biocompatibility. This study develops a one-step method to modify commercially available screen-printed electrodes (SPE) using laser-induced pyrolysis of DES, consisting of choline chloride and tartaric acid with dissolved nickel acetate and dispersed graphene. The electrodes were patterned using a 532 nm continuous-wave laser for the in situ formation of Ni nanoparticles decorated on graphene sheets directly on the SPE surface (Ni-G/SPE). The synthesis parameters, specifically laser power and graphene concentration, were optimized using the Nelder–Mead method to produce modified Ni-G/SPEs with maximized electrochemical response to dopamine. Electrochemical characterization of the developed sensor by differential pulse voltammetry revealed its broad linear detection range from 0.25 to 100 μM and high sensitivity with a low detection limit of 0.095 μM. These results highlight the potential of laser-assisted DES synthesis to advance electrochemical sensing technologies, particularly for the detection of biogenic amines.
... In this case, the average deposition rate is approximately 0.01 mm per second that results in an excessive duration of the deposition process. The main characteristics of the aforementioned methods are summarized in the table 1. [34] In contrast, in the current work, we used deep eutectic solvents (DESs) instead of solutions typically utilized in LCLD. As a result, it allows to significantly simplify the metal deposition procedure and increase the deposition rate of metals by more than a factor of 150. ...
... Therefore, DES can be considered as the promising solvents for the deposition of metals under the action of laser radiation. In our previous works, we optimized physical and chemical factors affecting the process of the formation of copper and nickel micropatterns [34]. It was shown that micropatterns with a high copper content can be fabricated using systems based on choline chloride, copper chloride and organic acids (citric or tartaric) [33]. ...
In this paper, we proposed rapid laser-induced synthesis of copper micropatterns on the surface of oxide glass from deep eutectic solvents (DESs) consisting of choline chloride, citric or tartaric acid and copper acetate as copper plating solutions. It was shown that upon irradiation with continuous-wave 532-nm laser radiation, it is possible to increase the deposition rate of copper and create micropatterns with a resistance close to the value of pure metal together with high adhesion to the substrate surface. This metallization method is favorable for the practical use of copper patterns, including in production of new printable microelectronic devices. Thus, we demonstrated the possibility of copper deposition on arbitrary three-dimensional surfaces. Moreover, the resulting copper micropatterns were tested as working electrodes for non-enzymatic glucose. Finally, the proposed technology can be successfully used for design and development of sensor platforms for the electrochemical analysis and microelectronic devices
... Therefore, DES can be considered as the promising solvents for the deposition of metals under the action of laser radiation. In our previous works, we optimized physical and chemical factors affecting the process of the formation of copper and nickel micropatterns [34]. It was shown that micropatterns with a high copper content can be fabricated using systems based on choline chloride, copper chloride, and organic acids (citric or tartaric) [33]. ...
In this paper, we proposed rapid laser-induced synthesis of copper micropatterns on the surface of oxide glass from deep eutectic solvents (DESs) consisting of choline chloride, citric or tartaric acid, and copper acetate as the copper plating solutions. It was shown that upon the 532-nm continuos wave laser irradiation, it is possible to increase the deposition rate of copper and create micropatterns with a resistance close to the value of pure metal together with high adhesion to the substrate surface. This metallization method is favorable for the practical use of copper patterns, including in the production of new printable microelectronic devices. Thus, we demonstrated the possibility of copper deposition on arbitrary three-dimensional surfaces. Moreover, the resulting copper micropatterns were tested as working electrodes for non-enzymatic glucose. Finally, the proposed technology can be successfully used for the design and development of sensor platforms for the electrochemical analysis and microelectronic devices.
Graphical abstract
... Previously, the physico-chemical factors affecting the formation of copper and nickel micropatterns have been optimized. In (Levshakova et al. 2022), it was shown that nickel micropatterns can be fabricated using systems based on choline chloride, nickel chloride or acetate and citric acid. It was demonstrated that the synthesized nickel micropatterns exhibit promising electrocatalytic characteristics for enzyme-free detection of dopamine (DA). ...
In this work, we proposed a rapid single-stage laser-induced fabrication of bimetallic micropatterns on the oxide glass surface using deep eutectic solvents (DESs) consisting of choline chloride, citric acid along with nickel, copper and cobalt acetates as metallization solutions. The resulting bimetallic micropatterns were tested as working electrodes for non-enzymatic determination of dopamine. The linear range for dopamine detection was found to be 1–500 µM, with sensitivity of 340.4 µA mM− 1 and 615.2 µA mM− 1 and detection limit of 0.36 µM and 0.51 µM for Ni-Cu and Ni-Co sensor, respectively. For the first time, bimetallic Ni-Cu and Ni-Co structures have been obtained from DESs for high-performance dopamine detection with great potential for further application in non-enzymatic sensing and biosensing.
... been optimized. In(Levshakova et al. 2022) it was shown that nickel micropatterns can be fabricated using systems based on choline chloride, nickel chloride or acetate and citric acid. It was shown that thesynthesized nickel micropatterns exhibit promising electrocatalytic characteristics for enzyme-free detection of dopamine (DA). ...
In this work, we proposed a rapid single-stage laser-induced fabrication of bimetallic micro-patterns on an oxide glass surface using deep eutectic solvents (DESs) consisting of choline chloride, citric acid along with nickel, copper and cobalt acetates as metallization solutions. The resulting bimetallic micropatterns were tested as working electrodes for non-enzymatic determination of dopamine. The linear range for dopamine detection was found to be 1–500 µM, with a sensitivity of 340.4 µA mM ⁻¹ and 615.2 µA mM ⁻¹ and a detection limit of 0.36 µM and 0.51 µM for Ni-Cu and Ni-Co sensor, respectively. For the first time, bimetallic Ni-Cu and Ni-Co structures have been obtained from DESs for high-performance dopamine detection with great potential for further application in non-enzymatic sensing and biosensing.
... DESs are inexpensive, eco-friendly solutions, which have the ability to dissolve metal salts in high concentrations and at significantly higher boiling points than water and common organic solvents [33][34][35]. The combination of these exceptional properties is heavily exploited for the synthesis of various functional materials [36][37][38], including the laser-assisted fabrication of copper and nickel electric contacts onto glass substrates [39,40]. Regarding chemical deposition with CW lasers, DESs based on choline chloride and organic acid have dramatically accelerated scanning rates (more than two orders of magnitude), compared to the regular aqueous solution (from 2.5 µm/s for water-based systems to~2 mm/s for DES) [41]. ...
In this study, we developed a method for the fabrication of electrically conductive copper patterns of arbitrary topology and films on dielectric substrates, by improved laser-induced synthesis from deep eutectic solvents. A significant increase in the processing efficiency was achieved by acceptor substrate pretreatment, with the laser-induced microplasma technique, using auxiliary glass substrates and optional laser post-processing of the recorded structures; thus, the proposed approach offers a complete manufacturing cycle, utilizing a single, commercially available, pulsed Yb fiber laser system. The potential implications of the presented research are amplified by the observation of laser-induced periodic surface structures (LIPSSs) that may be useful for the further tuning of tracks’ functional properties.
The use of photons to directly or indirectly drive chemical reactions has revolutionized the field of nanomaterial synthesis resulting in appearance of new sustainable laser chemistry methods for manufacturing of micro‐ and nanostructures. The incident laser radiation triggers a complex interplay between the chemical and physical processes at the interface between the solid surface and the liquid or gas environment. In such a multi‐parameter system, the precise control over the resulting nanostructures is not possible without deep understanding of both environment‐affected chemical and physical processes. The present review intends to provide detailed systematization of these processes surveying both well‐established and emerging laser technologies for production of advanced nanostructures and nanomaterials. Both gases and liquids are considered as potential reacting environments affecting the fabrication process, while subtractive and additive manufacturing methods are analyzed. Finally, the prospects and emerging applications of such technologies are discussed.
The development of renewable and efficient electrocatalysts for hydrogen evolution reaction (HER) is energetic for clean and green hydrogen production. Herein, we prepared the nanocomposites of narthangai leaves-derived activated carbon decorated-NiO (NiO/AC) by using the deep eutectic solvents (DES) process. The prepared nanocomposites showed an aggregated structure of AC-decorated NiO nanoparticles with a high specific surface area (118.6 m²/g) and large porosity. When utilizing the NiO/AC nanocomposite as an HER catalyst, the catalyst showed an excellent HER electrocatalytic behavior i.e., low overpotential (385 mV), very lower Tafel slope (127 mV/dec), and long-term stability. These owing HER features are considered accrediting to the coactive properties of the material active surface of NiO nanoparticles and the high conductivity of the AC nanoflakes. The results suggested that the DES-supported synthesized NiO/AC nanocomposites could play a significant role in electrocatalytic performance for wastewater treatment.
We investigated the influence of morphology of Ni microstructures modified with Au and Pt on their cell biocompatibility and electrocatalytic activity toward non-enzymatic glucose detection. Synthesis and modification were carried out using a simple and inexpensive approach based on the method of laser-induced deposition of metal microstructures from a solution on the surface of various dielectrics. Morphological analysis of the fabricated materials demonstrated that the surface of the Ni electrode has a hierarchical structure with large-scale 10 μm pores and small-scale 10 nm irregularities. In turn, the Ni-Pt surface has large-scale cavities, small-scale pores (1–1.5 μm), and a few tens of nanometer particles opposite to Ni-Au that reveals no obvious hierarchical structure. These observations were supported by impedance spectroscopy confirming the hierarchy of the surface topography of Ni and Ni-Pt structures. We tested the biocompatibility of the fabricated Ni-based electrodes with the HeLa cells. It was shown that the Ni-Au electrode has a much better cell adhesion than Ni-Pt with a more complex morphology. On the contrary, porous Ni and Ni-Pt electrodes with a more developed surface area than that of Ni-Au have better catalytic performance toward enzymeless glucose sensing, revealing greater sensitivity, selectivity, and stability. In this regard, modification of Ni with Pt led to the most prominent results providing rather good glucose detection limits (0.14 and 0.19 μA) and linear ranges (10–300 and 300–1500 μA) as well as the highest sensitivities of 18,570 and 2929 μA mM–1 cm–2. We also proposed some ideas to clarify the observed behavior and explain the influence of morphology of the fabricated electrodes on their electrocatalytic activity and biocompatibility.
In the current study, the method of Selective Surface Activation Induced by Laser (SSAIL) was used for the fabrication of metallic and bimetallic structures based on copper and gold on the surface of glass and glass-ceramics. It was shown that the fabricated electrodes are suitable for non-enzymatic detection of biologically essential analytes such as glucose. The implemented approach allows performing high-rate metallization of various dielectrics. Voltammetric methods were applied to evaluate the electrocatalytic activity of the obtained structures, which were used as working electrodes. The most promising results were revealed by copper-gold electrode structures manufactured on glass-ceramics. For these structures, sensitivity towards glucose sensing was 3060 μA mM-1 cm-2. The linear range of glucose detection varied between 0.3 and 1000 μM. Besides, the manufactured electrodes exhibited high selectivity and long-term stability.
In this work, the method of selective laser reductive sintering was used to fabricate the sensor-active copper and nickel microstructures on the surface of glass-ceramics suitable for non-enzymatic detection of glucose. The calculated sensitivities for these microsensors are 1110 and 2080 μA mM−1·cm−2 for copper and nickel, respectively. Linear regime of enzymeless glucose sensing is provided between 0.003 and 3 mM for copper and between 0.01 and 3 mM for nickel. Limits of glucose detection for these manufactured micropatterns are equal to 0.91 and 2.1 µM for copper and nickel, respectively. In addition, the fabricated materials demonstrate rather good selectivity, long-term stability and reproducibility.
Photonic curing has shown great promise in maintaining the integrity of flexible thin polymer substrates without structural degradation due to shrinkage, charring or decomposition during the sintering of printed functional ink films in milliseconds at high temperatures. In this paper, single-step photonic curing of screen-printed nickel (Ni) electrodes is reported for sensor, interconnector and printed electronics applications. Solid bleached sulphate paperboard (SBS) and polyethylene terephthalate polymer (PET) substrates are employed to investigate the electrical performance, ink transfer and ink spreading that directly affect the fabrication of homogeneous ink films. Ni flake ink is selected, particularly since its effects on sintering and rheology have not yet been examined. The viscosity of Ni flake ink yields shear-thinning behavior that is distinct from that of screen printing. The porous SBS substrate is allowed approximately 20% less ink usage. With one-step photonic curing, the electrodes on SBS and PET exhibited electrical performances of a minimum of 4 Ω/sq and 16 Ω/sq, respectively, at a pulse length of 1.6 ms, which is comparable to conventional thermal heating at 130 °C for 5 min. The results emphasize the suitability of Ni flake ink to fabricate electronic devices on flexible substrates by photonic curing.
In this work, copper circuits were fabricated on flexible polyimide (PI) substrates by high repetition rate femtosecond laser-induced selective local reduction of copper oxide nanoparticles (CuO NPs). The effects of laser pulse energy and laser scanning velocity on the quality of the copper circuit were studied. By optimizing laser processing parameters, we prepared a Cu circuit of a line width of 5.5 µm and an electrical resistivity of 130.9 µΩ·cm. The Cu/O atomic ratio of the Cu circuit reaches ∼10.6 and the proportion of Cu is 91.42%. We then studied the formation mechanism of the copper circuit by simulating the temperature field under the irradiation of high repetition rate femtosecond laser pulses. The results show that the thermochemical reduction reaction induced by the high repetition rate femtosecond laser reduces CuO NPs into Cu NPs. Under the thermal effect of the high repetition rate femtosecond laser, Cu NPs agglomerate and grow to form a uniform and continuous Cu circuit.
In this paper, we propose a fast and simple approach for the fabrication of the electrocatalytically active ruthenium-containing microstructures using a laser-induced metal deposition technique. The results of scanning electron microscopy and electrical impedance spectroscopy (EIS) demonstrate that the fabricated ruthenium-based microelectrode had a highly developed surface composed of 10 μm pores and 10 nm zigzag cracks. The fabricated material exhibited excellent electrochemical properties toward non-enzymatic dopamine sensing, including high sensitivity (858.5 and 509.1 μA mM−1 cm−2), a low detection limit (0.13 and 0.15 μM), as well as good selectivity and stability.
A novel simple laser digital patterning process to fabricate Ni‐based flexible transparent conducting panels using solution‐processed nonstoichiometric nickel oxide (NiOx) thin films and their applications for flexible transparent devices are reported in this study. A large‐scale synthesis route to produce NiOx nanoparticle (NP) ink is also demonstrated. A low‐power continuous‐wave laser irradiation photothermochemically reduces and sinters selected areas of a NiOx NP thin film to produce Ni electrode patterns. Owing to the innovative NiOx NP ink and substantially lowered applied laser power density, Ni conductors can be fabricated, for the first time to the best of the authors' knowledge, even on a polyethylene terephthalate substrate, which is known to have one of the lowest glass‐transition temperatures among polymers. The resultant Ni electrodes exhibit a high‐temperature oxidation resistance up to approximately 400 °C, and high corrosion resistance in tap water and even in seawater. Moreover, a superior mechanical stability of the Ni conductors is confirmed by tape‐pull, ultrasonic‐bath, bending/twisting, and cyclic bending (up to 10 000 cycles) tests. Finally, flexible transparent touch screen panels and electrical heaters are fabricated with mesh‐type Ni conductors to demonstrate possible applications. Ni‐based flexible transparent conducting panels are fabricated by a laser digital patterning process using solution‐processed NiOx thin films. Superior electromechanical properties of the conductors as well as high thermal stability against oxidation up to 400 °C and high corrosion resistance in seawater are verified. Successful demonstration of flexible touch screen panels and high‐temperature flexible transparent heaters confirms the potential applications.
p-type and n-type thermoelectric micropatterns were selectively fabricated via the reduction and reoxidation of CuO/NiO mixed nanoparticles using femtosecond laser pulses. The micropatterns were formed by raster scanning focused femtosecond laser pulses on a solution film containing CuO and NiO nanoparticles, ethylene glycol, and polyvinylpyrrolidone, followed by the removal of the non-irradiated nanoparticles. Cu–Ni was generated by reductive sintering of the CuO/NiO mixed nanoparticles at laser scanning speeds ranging from 5 to 20 mm/s and a laser fluence of 0.055 J/cm². In contrast, intense peaks corresponding to Cu2O and NiO were observed in the X-ray diffraction spectrum of the micropattern formed at a scanning speed of 1 mm/s, indicating that Cu2O and NiO were generated via the reoxidation of the reduced metals. The Seebeck coefficients of the micropatterns formed at a fluence of 0.055 J/cm² and scanning speeds of 5–20 mm/s were between − 32 and − 16 µV/K, whereas that of the micropattern formed at a fluence of 0.055 J/cm² and scanning speed of 1 mm/s was ~ 250 µV/K. These results suggest that the Seebeck coefficient depends on the generated n-type Cu–Ni and p-type Cu2O and NiO phases. A thermoelectric couple was fabricated by selectively fabricating p-type and n-type thermoelectric elements. The thermoelectric couple exhibited a thermoelectric voltage of 0.25 mV/K when a temperature gradient was applied between its hot and cold sides. The generated voltage was nearly consistent with the estimated voltage based on the Seebeck coefficient. The developed process for selective fabrication is expected to be useful for the direct writing of thermoelectric-type sensors.
We present an experimental study of double-pulse laser-induced forward transfer (LIFT) and jet formation from different metal donor films. The dynamics of the jet formation and propagation have been investigated by time-resolved shadowgraphy studies. The morphologies of the irradiated films have been studied by means of scanning electron microscopy analysis. The experiments have been performed with copper, gold and nickel–copper double-layer films and the results point out the ability of double-pulse LIFT method to form long liquid metal jets and to print micro-droplets with a limited dependence on the metal properties.
This paper presents the direct writing of thermoelectric couples composed of Cu–Ni alloy in ambient atmosphere. Patterns of Cu, Ni, and Cu–Ni alloys were directly written by the rapid heating and reduction of glyoxylic acid metal (Cu, Ni, and Cu/Ni mixed) complexes on glass substrates using femtosecond laser pulses without significant oxidation. The Seebeck coefficient of the patterns depended on the concentration ratio of Cu to Ni in the alloy, which could be controlled by the concentrations of the glyoxylic acid Cu/Ni mixed complex. A thermoelectric couple composed of p-type Cu and n-type Cu–Ni alloy generated an open-circuit voltage depending on the temperature gradient. This direct writing technique of pure metal and alloy allows various sensors to be printed in air.
This study developed a novel and simple method for fabricating high-temperature ultralight, fast responsive, flexible transparent Ni-based heaters using the laser digital patterning (LDP) process of a nonstoichiometric solution-processed NiO x ...
The design of the cost-effective, efficient, and durable electrocatalysts for hydrogen evolution reaction (HER) is of great importance in the field of clean and renewable energies. In this study, Ni/NiO nanocomposite supported on N-doped carbon nanoweb (Ni/NiO/NCW) hybrid materials are proposed as an efficient electrocatalyst for HER in alkaline media. A series of Ni/NiO/NCW hybrid catalysts were prepared via polymerization of polypyrrole (PPy) in the presence of a surfactant, followed by incipient wetness impregnation and heat treatment techniques. The resulting Ni/NiO/NCW hybrid catalysts exhibit an excellent electrocatalytic properties with a lower overpotential of 105.3 mV (vs RHE) at 10 mA cm⁻², a smaller value of Tafel slope (55.2 mV dec⁻¹) and almost 100% Faradaic efficiency. It also shows good stability in performance attenuation during continuous cyclic voltammetry sweeps for 1000 cycles. Its excellent electrocatalytic performance for alkaline hydrogen evolution reaction can be attributed to the synergistic effect associated with the morphological benefit of 3D N-doped carbon nanoweb and Ni/NiO heterostructure with the optimal ratio of Ni to NiO.
Direct laser writing of graphene electrodes is an emerging research field for the rapid fabrication of two-dimensional carbon electronic materials with wide applications, ranging from supercapacitors and batteries to sensors, electrocatalysts, actuators, etc. Many types of carbon-containing raw materials can be converted to graphene by one-step laser scribing, without complicated chemical synthesis routines, using a variety of lasers. This perspective categorizes the principles of direct laser writing of graphene, according to the different types of raw materials, different types of lasers, and different applications. The future directions of laser synthesized graphene are also discussed.
Copper is predominantly recovered from sulfide ores by pyrometallurgy – an energy intensive process requiring capture and treatment of released SO2. Whilst some copper ores are amenable to hydrometallurgy, chalcopyrite, the main copper mineral, is challenging to process in aqueous solutions due to surface passivation. The chalcopyrite surface may be less prone to passivation in non-aqueous solvents such as Ionic Liquids. Here we provide the first demonstration that electrochemistry in Deep Eutectic Solvents can solubilise and directly recover high purity copper from solution from three copper sulfide minerals: covellite (CuS), chalcocite (Cu2S) and chalcopyrite (CuFeS2). Cyclic voltammetry supported by EXAFS identifies the metal speciation in solution. In a choline chloride-ethylene glycol DES the main copper species present after dissolution of chalcocite and covellite was [CuCl4]2−. In the solution formed from chalcopyrite, a mix of CuII and CuI species were formed instead. In a choline chloride-urea DES, copper had a mixed chloride/O- or N-donor coordination, potentially altering electrochemical behaviour. Sulfide in the mineral is oxidised to sulfate without the generation of SO2 or H2S. The best selective recovery of copper (99 at%) from chalcopyrite was obtained with a mixed DES of 20 wt% choline chloride-oxalic acid and 80 wt% choline chloride-ethylene glycol. This demonstrates how design of the Deep Eutectic Solvents can enable selective copper recovery over iron in the electrowinning stage by changing solute speciation and redox properties.
The phenomenon of the laser chemical deposition of copper using deep eutectic solvents (DESs) on a dielectric substrate has been shown for the first time.
In this work, we reported in situ laser-induced synthesis of sensor-active copper‑silver microcomposite. This bimetallic microelectrode exhibits highly developed surface area and good electrical conductivity, and can be successfully used for glucose and alanine sensing demonstrating decent sensitivity (31,000 μА cm⁻² mМ⁻¹ for d-glucose and 11,177 μА cm⁻² mМ⁻¹ for l-alanine) and low limit of detection (2.8 μM for d-glucose and 0.83 μM for l-alanine). High sensor activity and good electrochemical characteristics of the synthesized material can be associated with the eutectic type of the Cu-Ag system. The implemented technique is quite useful for fabrication of new promising small size sensors for enzymeless determination of different biological analytes.
As evidenced by the growing applications of additive manufacturing, there is extensive value in customization, both in terms of materials chemistry and structure. Simultaneously, there is a drive towards miniaturization and complexity – making intricate, smaller features with higher resolution and greater materials diversity. Direct laser writing is a promising approach to the maskless patterning of a broad range of microscale materials. We employ a methodology using laser-induced solvothermal voxels, which combines the control of solvothermal chemistry with the patterning abilities of direct laser writing, enabling the synthesis and integration of oxides, metals, and mixed metal oxides and alloys. We present here a comprehensive analysis of the synthesis process, an expanded range of materials that can be easily fabricated through this direct laser writing method, and we explore how this process can be used for 2.5D topographical patterning and layering. Given the diversity of materials which we can access with this technique, the demonstrated ability for integration, and the opportunities for greater chemical complexity in mixed metal oxides, this direct laser writing method shows promise for applications including catalysis and sensing.
Our work proposed a facile strategy for selective fabricating the precise metalized patterns onto polymer substrates through laser direct structuring (LDS) technology using organocopper compounds. The copper oxalate (CuC2O4) and copper acetylacetonate [Cu(acac)2] which acted as laser sensitizer were first introduced into acrylonitrile-butadiene-styrene (ABS) matrix for prepare LDS materials. After the activation with 1064 nm pulsed near-infrared (NIR) laser, the Cu0 (metal copper) was generated from the CuC2O4 and Cu(acac)2, and then served as catalyst species for the electroless copper plating. A series of characterizations were conducted to investigate the morphology and analyze the surface chemistry of ABS/CuC2O4 and ABS/Cu(acac)2 composites. Specially, the X-ray photoelectron spectroscopy (XPS) analysis indicated that 58.3% Cu2+ in ABS/CuC2O4 was reduced to Cu0, while this value was 63.9% for the ABS/Cu(acac)2. After 30 min electroless copper plating (ECP), the conductivity of copper circuit on ABS/CuC2O4 and ABS/Cu(acac)2 composites were 1.22 × 107 Ω−1•m−1 and 1.58 × 107 Ω−1•m−1, respectively. Moreover, the decorated patterns and near field communication (NFC) circuit were demonstrated by this LDS technology. We believe that this study paves the way for developing organocopper-based LDS materials, which has the potential for industrial applications.
We report one-step in situ laser-induced synthesis of the conductive copper microstructures doped with iron, zinc, nickel, and cobalt with highly developed surface area. It was observed that the presence of chlorides of the aforementioned metals in the solutions used in our experiments increases the deposition rate and the amount of copper in the resulting deposits; it also leads to the deposit miniaturization. The laser deposition from solutions containing cobalt (II) chloride of concentration more than 0.003 M results in fabrication of copper microelectrode with better electrochemical properties than those deposited from solutions containing chlorides of other metals of the same concentration. Moreover, copper microelectrode doped with cobalt has demonstrated good reproducibility and long-run stability as well as sensitivity and selectivity towards determination of hydrogen peroxide (limit of detection-0.2 μM) and D-glucose (limit of detection-2.2 μM). Thus, in this article we have shown the opportunity to manufacture two-phase microcomposite materials with good electrical conductivity and electrochemical characteristics using in situ laser-induced metal deposition technique. These materials might be quite useful in development of new perspective sensors for non-enzymatic detection of such important analytes as hydrogen peroxide and glucose.
In this study, we used a facile approach to decorate Ni nanoparticles (Ni-NPs) with ethylene glycol followed by their adsorption on reduced graphene oxide (rGO) nanosheets for the development of enzyme free electrochemical glucose sensor. The effect of Ni-NP content (0.14, 0.28, 0.42, and 0.56 wt.%) on electrochemical properties and the molecular interaction of glucose with Ni-NPs/rGO in glucose sensing were evaluated. Ni-NPs/rGO showed significantly higher electrochemical performance for the glucose oxidation in alkaline solution compared to rGO. Specifically, 0.42% Ni-NPs/rGO revealed excellent performance for glucose determination with a wide linear range (0.25 μM to 1200 μM), a highly reproducible response and long-term stability with the calculated detection limit of 0.01 μM. Moreover, the reliability of the Ni-NPs/rGO sensor estimated using glucose concentration evaluation in human blood serum was confirmed. Ab initio calculations were employed to reveal molecular interactions of glucose with Ni-NPs/rGO. The results showed Ni13 cluster with icosahedral geometry facing the graphene sheet is the most stable structure. Furthermore, the glucose molecule was able to adsorb on the graphene sheet through Ni13 nanoclusters and the adsorption process is closely dependent on the orientation of Ni13 nanoclusters.
Nowadays, metal nanoparticles (NPs) have been considered as highly promising functional materials, impacting virtually all the fields of science and technologies. Numerous wet-chemical approaches have been developed to synthesize metal NPs with various components and structures. Although successful, impurities, such as additives and reaction residuals, usually remain in products. Recently, an alternative method, pulsed laser ablation in liquid (PLAL) phase has attracted increasing attention for colloidal NP preparation, since it can realize a chemical-free environment, leading to the formation of a “clean” NP dispersion. This unique feature makes the PLAL method and resulting metal NPs extremely attractive for catalytic applications, since catalytic reaction efficiency is strongly dependent on the surface feature of metal NPs. Usually, a surfactant-free, “bare” metal surface is highly desired for catalysis as it favors the access of the reactants to the surface active sites of metal NPs. Due to the absence of ligand or stabilizer molecules on the surface of PLAL-NPs, it is expected that these PLAL-NPs can exhibit higher catalytic activity in comparison to their chemically synthesized counterparts. In this review, we briefly introduce some recent advances on the synthesis of PLAL-metal NPs and some of their important catalytic applications.
In this study, we perform drop-on-demand (DOD) inkjet printing and the laser reductive sintering of precrystallized NiO nanoparticle (NP) ink under ambient conditions to obtain NiO/Ni hybrid electrode patterns on a highly localized area. By formulating an inkjet-printable and laser-reducible NiO NP ink, and by exploring the optimum conditions of the inkjet printing parameters, we generate stable droplets, enabling arbitrary shapes of NiO NP dot arrays or line patterns to be deposited. Subsequent short-time low-temperature sintering produces highly crystalline NiO electrodes. Furthermore, laser reductive sintering applied on deposited NiO NP patterns can successfully realize a selective transformation of the NiO into Ni electrodes under ambient conditions. Therefore, we can define either NiO or Ni electrodes, or a combination of the two on specific areas with precise amounts of ink. In addition, we identify the characteristics of the synthesized NPs, NP ink, NiO and Ni electrodes using various analytical methods.
Deep eutectic solvents (DESs) have been regarded as one of the most promising environmentally benign and cost-effective alternatives to conventional ionic liquids and volatile organic solvents. Aqueous mixtures of DESs have the potential to afford modified properties for specific applications. Densities and dynamic viscosities of a common and popular DES composed of choline chloride and urea in 1:2 molar ratio, named reline, and its aqueous mixtures in the temperature range 293.15 K to 363.15 K are reported. A decrease in density with increasing temperature is found to follow a quadratic expression. Excess molar volumes of the aqueous mixtures of reline are found to be negative at all temperatures and compositions. The absolute excess molar volume is found to decrease, in general, as the temperature is increased from 293.15 K to 323.15 K. For temperatures above 323.15 K, the excess molar volume does not change much with further increase in temperature to 363.15 K. The temperature dependence of dynamic viscosity of aqueous mixtures of reline in the temperature range 293.15 K to 363.15 K at all compositions is found to be better described by a Vogel-Fulcher-Tamman (VFT) model as opposed to an Arrhenius expression. Excess logarithmic viscosities for aqueous mixtures of reline are found to be negative at most temperatures and compositions; however, they become positive at 353.15 K and 363.15 K. The excess logarithmic viscosities of aqueous reline mixtures are in stark contrast to that reported for aqueous mixtures of DES glyceline, composed of choline chloride and glycerol in the same mole ratio, where the excess logarithmic viscosities are positive. Facile interstitial accommodation of water within H-bonded reline network as opposed to formation of extensive H-bonding is proposed to be the reason for this experimental observation. The important role of the H-bond donor as a constituent of DES is amply highlighted as it controls the interactions present in a DES and its aqueous mixtures.
This work is concerned with the kinetics of laser-induced reductive sintering of non-stoichiometric crystalline nickel oxide (NiO) nanoparticles (NPs) under ambient conditions. The mechanism of photophysical reductive sintering upon irradiation using a 514.5 nm continuous-wave (CW) laser on NiO NP thin films has been studied through modulating the laser power density and illumination time. Protons produced due to high-temperature decomposition of the solvent present in the NiO NP ink, oxygen vacancies in the NiO NPs, and electronic excitation in the NiO NPs by laser irradiation, all affect the early stage of the reductive sintering process. Once NiO NPs are reduced by laser irradiation to Ni, they begin to coalesce, forming a conducting material. In-situ optical and electrical measurements during the reductive sintering process take advantage of the distinct differences between the oxide and the metallic phases to monitor the transient evolution of the process. We observe four regimes: oxidation, reduction, sintering, and re-oxidation. A characteristic timescale is assigned to each regime.
We have developed a nanoparticle (NP) printing technique using Ni thin film lift-off from glass substrates after ultrafast irradiation in air. Unique interactions of ultrafast laser pulses with thin films allow for control over NP faceting and size distributions. Control is achieved by changing the laser fluence, film thickness, and film-substrate distance. We demonstrate 20 nm Ni film removal from substrates and rapid NP printing, with size distributions centered at a 6 nm diameter. When the Ni film thickness is lowered to 10 nm, NPs are printed with distributions peaked at a 2 nm diameter.
We developed an electrochemical sensor to detect acetaminophen by electrochemically co-depositing glutamic acid and gold nanoparticles on a single-walled carbon nanotube film (AuNP-PGA/SWCNT). Cyclic voltammetry indicated that the electrochemical oxidation of acetaminophen at the AuNP-PGA/SWCNT film electrode involved a two-electron, one-proton process and was pH dependent. Different pulse voltammograms of acetaminophen oxidation on the AuNP-PGA/SWCNT film electrode yielded a well-defined oxidation peak at 360 mV in 0.1 M phosphate buffered saline buffer (pH 7.2) with linear calibration from 8.3 to 145.6 μM (R2 = 0.997). The detection limit was estimated to be 1.18 μM. The proposed sensor is stable and reproducible from 1.15 to 5.21% with a relative standard deviation of 3.56%. The AuNP-PGA/SWCNT film electrode was able to detect acetaminophen in the presence of interfering ascorbic acid; two well-defined oxidation peaks, one for ascorbic acid at 0.15 V and the other for acetaminophen at 0.39 V, were detected. Furthermore, the fabricated sensor accurately measured the amount of acetaminophen in pharmaceutical samples. Together, these results indicate that our AuNP-PGA/SWCNT film is a promising platform for accurate and reproducible detection of acetaminophen.
The solubility of 17 commonly available metal oxides in the elemental mass series Ti through Zn have been determined in three ionic liquids based on choline chloride. The hydrogen bond donors used were urea, malonic acid, and ethylene glycol. The results obtained are compared with aqueous solutions of HCl and NaCl. Some correlation is observed between the solubility in the deep eutectic solvents and that in aqueous solutions but some significant exceptions offer an opportunity for novel solvato-metallurgical processes.
This study presents the wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior, of water droplets on the silicon wafer surface with periodical nanopatterns and hierarchical structures. This study fabricates one- and two-dimensional periodical nanopatterns using laser interference lithography (LIL). The fabrication of hierarchical structures was effectively achieved by combining photolithography and LIL techniques. Unlike conventional fabrication methods, the LIL technique is mainly used to control the large-area design of periodical nanopatterns in this study. The minimum feature size for each nanopattern is 100 nm. This study shows that the wetting behavior of one-dimensional, two-dimensional, and hierarchical patterns can be obtained, benefiting the development of surface engineering for microfluidic systems.
Laser-induced copper deposition from aqueous and aqueous–organic solutions: state of the art and prospects of research
- Kochemirovsky