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Atmospheric solution based processes are being developed for the fabrication of thin film photovoltaic devices. Deposition techniques such as electrodeposition, spin coating, spraying or printing are promising techniques to increase the throughput and reduce the cost per Watt of Copper-Indium-Gallium-Selenide (CIGS), Copper-Zinc-Tin-Sulphide (CZTS)...
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... plasma source used in this work is a dielectric barrier dis- charge (DBD) plasma jet operating at 14.16 kHz, 10 kV. The power consumed by the plasma is typically less than 10 W. The jet con- sists of a quartz tube with an inner diameter of 1.5 mm and a metallic high voltage electrode wrapped tightly around the quartz tube (Fig. 1). The ground electrode is positioned beneath a PVC sample holder and the plasma is driven by an in-house built half-bridge resonant power supply. The jet is located at a distance of 1 cm above the substrate being treated, as shown in Fig. 1. In this jet, the electric field between the wrapped ring electrode and the ground electrode is ...
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... an inner diameter of 1.5 mm and a metallic high voltage electrode wrapped tightly around the quartz tube (Fig. 1). The ground electrode is positioned beneath a PVC sample holder and the plasma is driven by an in-house built half-bridge resonant power supply. The jet is located at a distance of 1 cm above the substrate being treated, as shown in Fig. 1. In this jet, the electric field between the wrapped ring electrode and the ground electrode is largely in the axial direction, parallel to the car- rier gas flow through the quartz tube ( Walsh et al., 2010). The TEC10 substrate with its transparent conducting layer was allowed to float electrically. The atmospheric-pressure plasma ...
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... oxidative power of oxygen-derived species, such as atomic oxygen, singlet oxygen and ozone ( Liu et al., 2010), is critical for cleaning and activating glass surfaces. The ionised helium-oxygen admixture forms a plasma plume that extends beyond the glass tube into the sur- rounding ambient air and reaches the surface under treatment ( Fig. 1 and Fig. 2). ...
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... nm film thickness). The deposition rate achieved for the low-pressure vac- uum plasma treated substrate was 1.5 nm/min, (film thickness $45 nm). As a result of the thicker film, the transmittance of the atmospheric-pressure plasma treated sample was slightly lower than that of the other samples despite having an improved extinc- tion coefficient (Fig. 10(a)). The respective band gaps extracted using the Tauc plot ( Fig. 10(b)) are in agreement with those obtained using ellipsometry ( Fig. 9(b) and inset), and a shift towards higher energy is observed for the band gap of those films deposited on plasma cleaned substrates. The increase in the bandgap is consistent with the observed increase ...
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... vac- uum plasma treated substrate was 1.5 nm/min, (film thickness $45 nm). As a result of the thicker film, the transmittance of the atmospheric-pressure plasma treated sample was slightly lower than that of the other samples despite having an improved extinc- tion coefficient (Fig. 10(a)). The respective band gaps extracted using the Tauc plot ( Fig. 10(b)) are in agreement with those obtained using ellipsometry ( Fig. 9(b) and inset), and a shift towards higher energy is observed for the band gap of those films deposited on plasma cleaned substrates. The increase in the bandgap is consistent with the observed increase in the refractive index. The crystallinity of the films improves on ...
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... in the bandgap is consistent with the observed increase in the refractive index. The crystallinity of the films improves on the plasma cleaned substrates. The reduced density of defects results in an increase in the bandgap. The bandgaps mea- sured using ellipsometry are slightly lower than the values obtained using the Tauc plot method ( Fig. 9(b) inset and Fig. 10). The band gap has been extracted using the Tauc formula in the ellipsometric modelling (see Eq. (2)). The bandgap is defined as the point at which the extinction coefficient k is greater than zero. In the graphical method used in the Tauc plot, a tail of band states is neglected when extrapolating the ...
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... analysis was performed on the CdS films deposited on untreated, low-pressure vacuum plasma treated and atmospheric-pressure plasma treated TEC10 glass. Fig. 11 shows the O1s, Cd3d and S2p peaks to compare the chemical composition of each CdS thin film surface. The O1s, Cd3d and S2p peaks of the CdS films are more intense in the pre-treated samples, with the highest intensities observed for the surface pre-treated with the atmospheric-pressure plasma. Table 2 shows the percentages of C, Cd, O ...
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... of each CdS thin film surface. The O1s, Cd3d and S2p peaks of the CdS films are more intense in the pre-treated samples, with the highest intensities observed for the surface pre-treated with the atmospheric-pressure plasma. Table 2 shows the percentages of C, Cd, O and S detected on each sample. The ratios C/Cd, O/Cd and Cd/S are shown in Fig. 12. The reduction of carbon on the CdS films grown on the plasma treated surfaces did not alter the CdS stoichiometry. From the S2p spectra, the oxidation component at 168.3 eV corresponds to the formation of CdS:O with possible formation of CdSO 4 and/or CdSO 3 . This is in agreement with the atomic compositional analysis shown in Table ...
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... uniformity of the CdS layers deposited on atmospheric- pressure treated substrates was confirmed using SEM imaging (Fig. 13(c)). The films are free of voids and pinholes. The SEM images reveal the presence of uniform small crystallites. The grain size and the growth dynamics were affected by the substrate pre- treatment. The CdS thin films deposited on ATM pressure plasma treated TEC10 showed large crystallites $200 ± 0.01 nm in size. The grain size of CdS ...
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... pre- treatment. The CdS thin films deposited on ATM pressure plasma treated TEC10 showed large crystallites $200 ± 0.01 nm in size. The grain size of CdS films deposited on low-pressure vacuum plasma treated TEC10 is $140 ± 0.01 nm. In comparison, the grain size of the CdS films deposited on the untreated substrate was much smaller $100 ± 0.01 nm (Fig. 13(a)). The grain size was cal- culated as an arithmetic average over 10 measurements, by using the AxioVision LE64 ...
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... microscopy was used to analyse the surface of the films and detect any pinholes or voids in the CdS thin films. Pinholes can be detected by using a light source deployed underneath the sam- ple. If pinholes are present, bright spots appear in the images (Fig. 14). Voids were present in the CdS films deposited on untreated surfaces with a size measured to be $3 ± 0.9 lm (as an average taken over 10 measurements). The CdS films deposited on atmospheric-pressure and low pressure vacuum plasma treated substrates appeared uniformly covered, and void and pinhole free. These results are consistent ...
Citations
... Reprinted from [14] under under the terms of the Creative Commons CC-BY license Planar or cylindrical consist of an insulating electrode and a grounded electrode. The DBDs are scalable, efficient, and have short processing times [10,11]. ...
... Reprinted from [14] under under the terms of the Creative Commons CC-BY license A runnel of charged particles, including ions and electrons, is called a corona, and it is accelerated by an electric field. It is created when a gaseous space gap, such as one containing air or another gas, is exposed to a voltage high enough to cause a series of high-velocity particle collisions with neutral molecules, leading to the creation of more ions. ...
... Reprinted from [14] under under the terms of the Creative Commons CC-BY license A neutral gas under an electrical field is the primary source to produce the APP. A gas is excited using direct current or alternating current at frequencies varying from low to several GHz while it is under atmospheric pressure. ...
Biopolymers have intrinsic drawbacks compared to traditional plastics, such as hydrophilicity, poor thermo-mechanical behaviours, and barrier characteristics. Therefore, biopolymers or their film modifications offer a chance to create packaging materials with specified properties. Cold atmospheric plasma (CAP) or Low temperature plasma (LTP) has a wide range of applications and has recently been used in the food industry as a potent tool for non-thermal food processing. Though its original purpose was to boost polymer surface energy for better adherence and printability, it has since become an effective technique for surface decontamination of food items and food packaging materials. These revolutionary innovative food processing methods enable the balance between the economic constraints and higher quality while ensuring food stability and minimal processing. For CAP to be considered as a viable alternative food processing technology, it must positively affect food quality. Food products may have their desired functional qualities by adjusting the conditions for cold plasma formation. Cold plasma is a non-thermal method that has little effects on the treated materials and is safe for the environment. In this review, we focus on recent cold plasma advances on various food matrices derived from plants and animals with the aim of highlighting potential applications, ongoing research, and market trends.
... 8 Therefore, in the low-temperature AP plasma, diverse highly reactive species and energetic electrons exist despite the low gas medium temperature, and this nonthermal property is advantageous for applications in the treatment of heat-sensitive materials such as biological tissues, organic and polymeric materials, and aqueous solutions. [9][10][11][12][13] The AP plasma jet (APPJ) device, which implements low-temperature glow plasma only with a conduit with electrodes, discharges the gas delivered through the conduit at high voltage and transfers the plasma jet and its by-products out of the conduit. [14][15][16][17] The APPJ device is greatly beneficial because low-temperature plasma can easily be created at atmospheric pressure using an inert gas (argon or helium) and can be transported in close proximity to the target site due to its conduit-shaped structure. ...
Herein, we describe a new flexible atmospheric pressure plasma jet device composed of hollow-core optical fibers and introduce two potential applications of the device: endoscopic plasma treatment and decomposition of aqueous phosphorus compounds. The proposed device is 1.6 m long and highly flexible, has a small probe size of several hundred micrometers, and spatially separates the plasma jet from the electrical input, making it very suitable for treatment through the biopsy channel of a conventional endoscope. Because the wire electrode of the fabricated atmospheric pressure plasma jet device is thoroughly isolated inside the hollow of the optical fiber, the device produces a plasma column in an identical discharge state regardless of external environmental conditions. As a result, the device can operate safely and steadily in highly humid environments, such as underwater, which can be utilized to decompose phosphorus compounds in fresh water.
... Low-temperature plasma treatment can increase the wettability of the glass surface 21,22 . The water contact angle (WCA) of the substrates before the plasma treatment was 44°, and plasma treatment significantly reduced the WCA to values less than 10°. ...
Single quantum dots (Qdots) are often used in the field of single-molecule imaging. Qdots are sensitive to changes in the physical interactions between the Qdots and the surrounding materials. However, the spectral changes in a single Qdot emission have not been studied in detail. Low-temperature plasma treatment of glass surfaces reduced the intensity of the 655 nm emission peak of Qdot655 on glass surfaces, but did not significantly change the intensity of the 580 nm emission. Silanization of the glass surface increases the thickness of the silane layer, and the 655 nm emission peak increased. When single Qdots on the untreated glass were imaged, plasma treatment decreased the intensity of red emission and increased yellow emission. When Qdots were brought close to the glass surface in the range of 28–0 nm, the red emission intensity decreased and the yellow emission intensity increased slightly. When single actin filaments were labeled with Qdots, fluctuations of the yellow and red emission of the Qdot were detected, which reflected the very small distance changes. Our results indicate that the local interaction of Qdots with the glass surface improves the spatial and temporal resolution of optical measurements of biomolecules labeled with Qdots.
... The non-equilibrium discharge behavior owing to partial ionization allows to attain high electron energies in the plasma medium while retaining ions and neutral species at room temperature [8]. The presence of various radicals and highly energetic electrons at low gas temperatures indicates that nonthermal AP plasma is particularly advantageous when processing heat-sensitive materials, such as organic materials, polymers, and volatiles [9][10][11][12][13]. In addition, because there are no bulky chambers or complicated vacuum components in the plasma generation system, and no chemical waste is generated after the process, material processing with AP plasma is generally considered an eco-friendly process with the ad-vantages of having a simple overall experimental setup, fast processing, and easy maintenance. ...
In this study, we describe an atmospheric pressure plasma jet (APPJ) device made of four-bore tubing operable in inhospitable humid environments and introduce two potential applications of liquid material processing: decomposition of aqueous phosphorus compounds and solution-plasma polymerization. A four-bore tube was used as the plasma transfer conduit and two diagonal bores contained metal wires. In the proposed APPJ device, the metal wires serving as electrodes are completely enclosed inside the holes of the multi-bore glass tube. This feature allows the APPJ device to operate both safely and reliably in humid environments or even underwater. Thus, we demonstrate that the proposed electrode-embedded APPJ device can effectively decompose aqueous phosphorus compounds into their phosphate form by directly processing the solution sample. As another application of the proposed APPJ device, we also present the successful synthesis of polypyrrole nanoparticles by solution plasma polymerization in liquid pyrrole.
... Furthermore, it has been proved that the non-perpendicular CAP treatment of silver thin film result in the significant variations in the Ag NPs size (Hosseinpour et al. 2019). In addition, the CAP treatment of the glass substrate improves the Ag NPs deposition rate, increases the thin film adhesion as well as the density and compactness of the deposited Ag NPs; leading to the fabrication of pinhole-free thin films (Lisco et al. 2017); resulting in the bacterial detection based on protein adsorption (Wigginton et al. 2010). CAP treatment is an environmentally benign technology, considered as a surface modification technique for such materials as polymers (Reche et al. 2016), or inorganic materials (e.g. ...
... It has been reported that the deposition techniques such as sputtering, electrodeposition, and spin coating require surface treatment of the substrate with atmospheric pressure plasma prior to the deposition of the thin film (Lisco et al. 2017). This is due to the fact that atmospheric-pressure plasma treatment of the substrate improves the Ag nanoparticles (NPs) deposition rate, increases the thin film adhesion as well as the density and compactness of the deposited Ag NPs; leading to the fabrication of pinhole-free thin films (Lisco et al. 2017). ...
... It has been reported that the deposition techniques such as sputtering, electrodeposition, and spin coating require surface treatment of the substrate with atmospheric pressure plasma prior to the deposition of the thin film (Lisco et al. 2017). This is due to the fact that atmospheric-pressure plasma treatment of the substrate improves the Ag nanoparticles (NPs) deposition rate, increases the thin film adhesion as well as the density and compactness of the deposited Ag NPs; leading to the fabrication of pinhole-free thin films (Lisco et al. 2017). The presence of pinholes in the silver thin film surface indicates to the sparse distribution of bacteria along the sensor surface. ...
In this study, for the first time, to our knowledge, a biosensor was produced using cold atmospheric plasma (CAP) treatment of silver thin film surface with non-perpendicular incidence angle for identification of Escherichia coli in distilled water. Field emission scanning electron microscopy (FESEM) exhibits that before deposition, non-perpendicular CAP treatment of glass surface substrate leads to the production of pinhole-free silver thin film. The results of atomic force microscopy (AFM) and curve fitting show that non-perpendicular CAP treatment of this pinhole-free silver thin film indicates to the appearance of Ag NPs with smaller size and larger surface area compared to untreated silver film deposited on the untreated glass substrate. The silver-based pinhole-free SPR biosensor produced with non-perpendicular CAP treatment of both glass substrate and silver film shows E. coli detection in the distilled water in the range of 104 colony forming unit (CFU/ml) to 108 CFU/ml with better sensitivity compared to the untreated silver-based SPR biosensor. HIGHLIGHTS
The glass substrate was treated using CAP for improving the silver film adhesion.;
FESEM analysis was performed for observation of pinholes in thin film.;
A silver-based SPR biosensor was fabricated using non-perpendicular CAP treatment for E. coli detection in water.;
The effect of non-perpendicular CAP on the performance parameters of pinhole-free silver biosensor was studied.;
... [17][18][19], equipment for plasma etching of the semiconductor and dielectric films can be employed for radio frequency (RF) hydrogen and/or argon plasma treatment, which is a very promising method for the modification of semiconductor and dielectric layers, including the layers of nanostructured materials. Great interest in studying the physics of RF plasma as an ion source is associated with its traditional use for the formation of various film coatings [20], and its possible use to solve some of physical and technical problems [21], including the use of plasma to clean the surface of films after synthesis [22][23][24]. Indeed, the CZTS-based SC has also demonstrated an efficiency exceeding 12% [25], which is presently a record for this absorber. ...
Cu2ZnSnS4 (CZTS) thin films deposited using direct current magnetron sputtering and sulfurized at argon atmosphere pressures of 950, 460, and 50 mbar are studied in a view of solar cell absorber fabrication. The main novelty in the work is the influence of the radio frequency (RF) electromagnetic field treatment on the Cu2-xS secondary phase. The treatment reduces the amount of the Cu2-xS secondary phase, which is confirmed by Raman spectroscopy. The RF effect is long-term, at least one year later. So, this treatment is a promising technique to achieve higher purities of CZTS absorber layers for solar cells.
... This layer contains organic contaminants that hinder the quality of various deposition methods. Atmospheric pressure plasma pretreatment of glass prior to thin film deposition is studied as a unique cleaning and activation technique, which is an environmentally friendly dry alternative to the commonly used wet chemical pre-treatment [1] . Diffuse coplanar surface barrier discharge (DCSBD) operating in ambient air is a plasma source with application potential for surface treatment of various materials. ...
Flexible ultra-thin glass is used as a substrate or packaging material in microelectronics engineering, where the level of cleanliness determines the quality of the final product. Surface properties of glass are governed by a surface nano-layer. Besides cleaning from coarse impurities, the demand is also for nano-decontamination, where standard cleaning proves insufficient. In microelectronics and printed flexible electronics, the bonding of thin structures deposited using printed conductive inks on glass substrates is of essential importance. The non-thermal, atmospheric-pressure plasma generated by diffuse coplanar surface barrier discharge (DCSBD) was studied as an effective pre-treatment method for cleaning and activation of glass surfaces, implementable into large-scale in-line manufacturing. Two industrial adaptations of DCSBD system were applied on two types of ultra-thin flexible glass to compare the effects of plasma treatment of glass in both relaxed, and bent state. DCSBD "Air-pillow" with a planar discharge unit is designed for contactless treatment of smooth flat large-area surfaces. A roll reactor with a concavely curved DCSBD unit is intended to exemplify its integration into roll-to-roll manufacturing. The effect of plasma treatment and its stability was analyzed with water contact angle measurement and X-ray photoelectron spectroscopy. Significant wettability improvement was achieved with both applied DCSBD geometries, with better effect uniformity and durability after using the DCSBD in the planar configuration.
... In contrast, deposition favors high adsorption and low desorption rates in order to build material on a surface [39]. Surface activation, in broad terms, utilizes balanced adsorption/desorption processes in order to alter the bonds or increase the number of reactive sites of the surface [40,41]. ...
Plasma surface treatment is a widely used process that modifies materials surface
properties so as to improve cleaning, coating, thin film deposition, printing, painting, adhesive bonding, etc. Plasma is usually generated by ionizing one or two gas phases. High purity homonuclear gases: Ar, N2, O2, or compound gases: CF4, SF6, etc. are frequently used as the plasma generation gas phase for surface treatment. These plasmas are often limited by specific materials surface treatment either for hydrophobic or hydrophilic treatment. Water plasma consists of positive and negative species, which have the potential to tune the surface from hydrophilic to hydrophobic or from hydrophobic to hydrophilic. Water plasma has been reported to be used for plasma cutting, but not on surface treatment.
This project aims to design a low power H2O vapor plasma generation system and
investigate H2O vapor as a universal processing gas for tuning surface adhesion properties of common semiconductor materials. An ultrasonic nebulizer was used to produce vapor from liquid H2O. Construction of a radial dielectric barrier discharge plasma generator allowed for the production of a high density filamentary plasma. The designed H2O vapor plasma system is demonstrated via surface modification. Using H2O vapor as a working gas, the surfaces of before and after plasma-treated polytetrafluoroethylene (PTFE), semiconductor grade [100] Si wafer, and thin-film Cu deposited on [100] Si wafer are investigated with contact angle measurement, atomic force microscopy, scanning electron microscopy. RMS values for all samples remained
very close to RMS values of the surfaces before treatment. Based on Wenzel theory, roughness-induced surface change is insufficient as a sole method of altering contact angles. It suggests that H2O plasma treatment might lower the surface energy of these materials. Specific to [100] Si, the surface energy reduction is attributed to hydroxyl groups from the H2O plasma which serve to functionalize the Si surface, making it superhydrophilic. The H2O plasma generated in this project was able to reduce the contact angle for all sample types.
... Processing: The atmospheric-pressure plasma (APPT) source used in the present study was an in-house built dielectric barrier discharge (DBD) plasma jet operating at 38.72 kHz, 10 kV at atmospheric pressure [46]. The typical power consumption of the plasma jet is less than 10 W. The jet nozzle consists of a quartz tube with an inner diameter of 1.5 mm and a metallic high voltage electrode wrapped around the quartz tube. ...
In the present study, the effect of atmospheric pressure plasma treatment (APPT) on polymethyl methacrylate (PMMA) substrates was investigated in terms of both the chemical and topographical changes introduced to the polymer surface and its influence on PMMA-to-glass adhesion. The use of a silane-based primer in this bonding system was also studied. The changes introduced to the PMMA surface, as a result of plasma processing, were identified using a combination of: X-ray photoelectron spectroscopy (XPS); atomic force microscopy (AFM), and; contact angle analysis (CA). Degreased only and APPT treated PMMA was then bonded to glass using a polydimethylsiloxane (PDMS)-based adhesive and the influence of plasma processing on adhesion performance was determined using the single lap shear (SLS) test geometry. SLS testing of the as-bonded PMMA-to-glass structures was performed as a function of various PMMA surface treatment conditions, and, after exposure of the bonded joints to multiple temperatures in order to assess the effect of the surface treatment on the strength of these joints. It was found that APPT treatment, with various gas mixtures, lowers the water contact angle of PMMA, and increases its surface free energy. The plasma gases used were argon, helium and oxygen, either on their own or in combination. The chemical composition of the plasma modified PMMA surfaces showed an increase in the level of oxygen present and a corresponding decrease in carbon content, as observed by XPS. Furthermore, AFM indicated a significant change in the topography of the PMMA surface after APPT exposure with a 100–200% increase in mean roughness values with optimised plasma conditions.
The above-mentioned physicochemical changes to the PMMA surface led to much improved adhesion of the PMMA-to-glass. APPT treatment improved the strength of the SLS joints from 0.28 MPa to 0.58 MPa. In addition, plasma treated PMMA used in combination with a silane-based primer gave a significant further enhancement in observed adhesion levels with SLS values increasing up to 1.56 MPa. Moreover, the adhesion strength of the bonded samples remained stable after both high temperature exposure at 70 °C and temperature cycling with exposure of the bonded joints from −50 °C to 70 °C. This temperature range had negligible effect on the strength of the adhesive joints after 30 thermal cycles.
... Atmospheric pressure dielectric barrier discharges have gained renewed interest in recent years due to their use in emerging applications such as plasma medicine [1], plasma agriculture [2,3], treatment of liquids [4], plasma catalysis [5][6][7], and preparation and processing of materials [8][9][10]. Arguably, the most established use of dielectric barrier discharges is the generation of ozone [11]. ...
Understanding the production mechanisms of ozone and other reactive species in atmospheric pressure dielectric barrier discharges (DBDs) has become increasingly important for the optimization and commercial success of these plasma devices in emerging applications, such as plasma medicine, plasma agriculture, and plasma catalysis. In many of these applications, input power modulation is exploited as a means to maintain a low gas temperature. Although the chemical pathways leading to ozone production/destruction and their strong temperature dependence are relatively well understood, the effect of the on-time duration on the performance of these modulated DBDs remains largely unexplored. In this study, we use electrical and optical diagnostics, as well as computational methods, to assess the performance of a modulated DBD device. The well-established Lissajous method for measuring the power delivered to the discharge is not suitable for modulated DBDs because the transients generated at the beginning of each pulse become increasingly important in short on-time modulated plasmas. It is shown that for the same input power and modulation duty-cycle, shorter on-time pulses result in significantly enhanced ozone production, despite their operation at slightly higher temperatures. The key underpinning mechanism that causes this counter-intuitive observation is the more efficient net generation rate of ozone during the plasma on-time due to the lower accumulation of NO2 in the discharge volume.
