Effect Of Oxygen Plasma Treatment Research Articles

Effect of Oxygen Plasma Treatment on the Performance of GQDs-Modulated InGaZnO Thin-Film Transistors

Effect of Oxygen Plasma Treatment on the Performance of GQDs-Modulated InGaZnO Thin-Film Transistors

Enhanced CO2 Sensing by Oxygen Plasma-Treated Perovskite-Graphene Nanocomposites.

Carbon dioxide (CO2) is a major greenhouse gas responsible for global warming and climate change. The development of sensitive CO2 sensors is crucial for environmental and industrial applications. This paper presents a novel CO2 sensor based on perovskite nanocrystals immobilized on graphene and functionalized with oxygen plasma treatment. The impact of this post-treatment method was thoroughly investigated using various characterization techniques, including Raman spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The detection of CO2 at parts per million (ppm) levels demonstrated that the hybrids subjected to 5 min of oxygen plasma treatment exhibited a 3-fold improvement in sensing performance compared to untreated layers. Consequently, the CO2 sensing capability of the oxygen-treated samples showed a limit of detection and limit of quantification of 6.9 and 22.9 ppm, respectively. Furthermore, the influence of ambient moisture on the CO2 sensing performance was also evaluated, revealing a significant effect of oxygen plasma treatment.

Effect of oxygen plasma-treatment on surface functional groups, wettability, and nanotopography features of medically relevant polymers with various crystallinities

The surface properties of polymeric biomaterials play a crucial role in their biocompatibility and performance. This study explores the application of cold oxygen plasma treatment as a versatile technique for surface modification of polymeric materials with different degrees of crystallinity: crystalline high-density polyethylene (HDPE), crystalline-amorphous poly(chloro‑paraxylylene) (parylene C), and amorphous aromatic polyether-based polyurethane (PU). The investigations focus on the generation of surface functional groups and hydrophilicity, as well as nanotopography. X-ray photoelectron spectroscopy (XPS) analysis confirmed the generation of oxygen-containing functional groups, resulting in controlled wettability (water contact angle), while atomic force microscopy (AFM) showed topography modifications in the nanoscale. At the same time, it was revealed that oxygen plasma treatment did not affect the bulk properties (confirmed by TG and XRD). The effects of the same plasma treatment conditions varied significantly among the different polymers studied, depending on their crystallinity. This was discussed in terms of the preferential etching of amorphous regions in the polymeric structures. The findings emphasize the advantages of oxygen plasma treatment for tailoring the surface properties of polymeric biomaterials, highlighting its significance for biomedical applications.

Complementary spectroscopic and electrochemical analysis of the sealing of micropores in hexamethyldisilazane plasma polymer films by Al2O3 atomic layer deposition

In the present study, the effects of oxygen plasma treatment and subsequent 2 nm thin Al2O3 film deposition by atomic layer deposition on about 30 nm thick hexamethyldisilazane polymer layers are investigated by using a combination of spectroscopic and electrochemical analysis. The investigations focus on the microporosity of the corresponding films and their structural changes. Upon oxygen plasma treatment, the surface near region of the films is converted into SiOx, and the microporosity is increased. Atomic layer deposition of Al2O3 on the plasma oxidized films leads to the decrease of pore sizes and an effective sealing. A correlation between the film microporosity and the change of hydroxyl groups of the films with the adsorption of water was established by ellipsometric porosimetry and in situ Fourier transform infrared (FTIR) spectroscopy. Moreover, electrochemical analysis provided complementary information on the electrolyte up‐take in the differently conditioned thin films.

The Effect of Oxygen Plasma Treatment on Wrinkle Resistance of Cellulose Acetate Based Fabric

ABSTRACT In this study, cellulose acetate-based fabrics were subjected to a resin-based wrinkle-resistant treatment. The fabric samples were treated with oxygen plasma for 1 and 5 minutes with a power of 100W prior the wrinkle-resistance finishing to enhance wrinkle resistance. The surface morphology and functional groups of samples were analyzed with scanning electron microscopy and Fourier transform infrared spectroscopy, respectively. The angle of wrinkle-resistance and tensile strength of samples were investigated in accordance with resin type and plasma treatment. Scanning electron microscope micrographs reveal that plasma treatment generates microscopic grooves and micro-cracks on the sample surfaces, resulting in an etching effect. Furthermore, the samples have been successfully treated with resin-based wrinkle-resistant finishing. The results of Fourier transform infrared spectroscopy show that no significant alterations in functional groups formed in the acetate fibers posterior to plasma treatment. The wrinkle-resistance angle of cellulose acetate cloth pre-treated with oxygen plasma and wrinkle-resistance resin was significantly improved, according to the results. The high wrinkle resistance result was obtained for warp direction 113.5 ± 3.5 and weft direction 102 ± 3. Furthermore, the wrinkle resistance data were investigated using MATLAB R2020b to predict one-way ANOVA with the main factor, plasma treatment, and the interaction impact was extremely significant (P < .05). The ANOVA results resemble that plasma treatment has an influence on sample wrinkle resistance. Furthermore, with plasma treatment, sample tensile strength increases from 525.15 N to 530.76 N, but with wrinkle-resistance resin, it decreases. Consequently, plasma pre-treatment and wrinkle-resistance resin are anticipated to suit both the needs of eco-friendly and high-quality finishing methods for textile materials.

Effect of Oxygen Plasma Treatment on Wheat Emergence and Yield in the Field.

This paper investigates the effects of an inductively coupled, radio frequency oxygen plasma on the plant emergence and crop yield of wheat in field growth conditions. Wheat seeds of eight different cultivars were plasma-treated using conditions selected based on preliminary experiments. Additionally, a control sample, as well as seeds treated with fungicide, an eco-layer, or a plasma + eco-layer combination, were planted in parallel. Four cultivars per harvest year were used. Plant emergence (plants/m2) and yield (kg/ha) were followed. There was little variation among the control and the various treatments regarding plant emergence. Regarding yield, there were statistically significant differences, but no discernible trend was seen when comparing the individual treatments. In the case of several cultivars, plasma-treated seeds performed as well as the control, but there was a significant increase in yield only in the case of cultivar 88.5 R. In several cases, yield of plants for plasma-treated seeds was also lower than the control. Our results demonstrate that the response of wheat yield to plasma treatment, as well as to other seed treatments, differs depending on the wheat cultivar.

Study of oxygen plasma treatment on solution-processed SnO x thin-film transistors

In this study, the effect of oxygen plasma treatment (OPT) on the electrical performance of the SnO x thin film transistors (TFTs) were investigated. The SnO x thin films were fabricated by solution process and integrated into the TFTs as channels. According to the x-ray photoelectric spectroscopy analysis, the oxygen vacancies in the SnO x thin films are significantly reduced after OPT. The electrical performances of the SnO x TFTs treated with various plasma power and treatment time were systematically studied. Compared with untreated SnO x TFT, the one with OPT of 40 W for 90 s exhibits optimum electrical performance, including the variation of the current on/off ratio (I on/I off) from ∼103 to 107 and threshold voltage (V TH) from −10.78 to 3.97 V. Meanwhile, the operation mode of the SnO x TFTs is changed from depletion mode to enhancement mode. When the SnO x TFT is integrated with high-k Al2O3 dielectric, the TFT exhibits better electrical performance, including the V TH of 0.14 V, an I on/I off of 107, a field-effect mobility (µ FE) of 5.57 cm2 V−1 s−1, and a subthreshold swing of 570 mV dec−1. These results prove that the OPT process for SnO x TFTs is a facile and efficient method in the flat panel display industries.

Effect of oxygen plasma treatment on the performance of recessed AlGaN/GaN Schottky barrier diodes

The treatment effect of the oxygen plasma on the performance of recessed AlGaN/GaN Schottky barrier diodes has been investigated. After the oxygen plasma treatment, the turn-on voltage and reverse leakage current are slightly changed, while the current collapse could be effectively mitigated. The X-ray photoelectron spectroscopy results suggest that a thin surface oxide layer is formed by the oxygen plasma treatment, which is responsible for the reduced current collapse. In addition, the device treated by oxygen plasma has a relatively more inhomogeneous barrier height.

Effect of Oxygen Plasma Treatment on the Structure and Mechanical Properties of Bilayer Graphene Studied by Molecular Dynamics Simulation

Effect of Oxygen Plasma Treatment on the Structure and Mechanical Properties of Bilayer Graphene Studied by Molecular Dynamics Simulation

Hybrid Plasma-Liquid Treatment of Carbon Nanotubes for Application in Direct Absorption Solar Thermal Collectors

Covalent functionalization of carbon nanotubes (CNTs) with oxygen-based or nitrogen-based functional groups is one of the most popular techniques to modify the surface energy and inherent properties of the CNTs.1 This functionalization generates interest for a broad range of applications including mechanically superior advanced composites,2 more sensitive gas sensors,3 enhanced energy storage materials4 or ultra-conductive fibers.5 As an alternative to the harsh chemicals used by traditional chemical functionalization, plasma-based surface treatments can be used with great efficacy and reduced reaction times, providing an array of application-specific benefits.Awareness of the environmental pollution caused by fossil fuels and the ever-increasing demand for energy has driven research focussed on zero-carbon renewable energy sources. Conscious of this, direct absorption solar thermal collectors are gaining prominence, both for domestic heating and steam generation. CNTs have been investigated as an additive to take advantage of the near blackbody absorption and high thermal conductivity to improve system efficiency. Critical to the success of the additive nanoparticles is the stability in the fluid, however, due to their high surface energy CNTs tend to agglomerate which can limit the efficacy of their integration into real-world products.In this work, macroscopic ribbon-like assemblies of carbon nanotubes are functionalized by plasma-induced non-equilibrium electrochemistry (PiNE) implemented through a simple direct current-based plasma-liquid system. This system utilizes the plasma-generated species in an electrolyte of 10 %vol ethanol in water, with or without a nitrogen precursor, for the oxygen and/or nitrogen functionalization of the carbon nanotube assembly. For this treatment, a ribbon-like piece of CNT was used as the anode and a helium plasma discharge triggered by applying 10 mA and 1 - 1.6 kV to act as the cathode. The plasma-generated species are then expected to migrate towards the CNTs and functionalize the sidewalls.The oxygen content is shown to be increased by between 70 % and 300 % when the treatment solution of 10 %vol ethanol is used in the ribbon electrode configuration. When ethylenediamine is added as a nitrogen precursor, the atomic concentration of nitrogen reaches 23 %, with amine groups, pyrrolic groups and graphitic nitrogen observed in the x-ray photoelectron spectra. This nitrogen content is unmatched in quantity when compared to either a simple soaking procedure or an electrolysis process with a platinum foil replacing the plasma as the counter-electrode. This demonstrates that the plasma either directly or indirectly, through plasma-generated species, facilitates and enhances the availability of nitrogen from the ethylenediamine precursor. The potential plasma-induced chemical pathways which lead to the functionalization of the CNTs are also investigated and discussed.In the application of a direct absorption solar collector system, it is found that the covalent functionalization provided by the plasma-liquid system enhances the stability of the CNT-ethylene glycol nanofluid, with the oxygen-functionalized samples producing the most stable nanofluids. This is explained through the lower value for contact angle measurements, suggesting greater hydrophobicity of the CNTs.References(1) Mallakpour, S.; Soltanian, S. Surface Functionalization of Carbon Nanotubes: Fabrication and Applications. RSC Adv. 2016, 6 (111), 109916–109935. https://doi.org/10.1039/c6ra24522f.(2) Williams, J.; Broughton, W.; Koukoulas, T.; Rahatekar, S. S. Plasma Treatment as a Method for Functionalising and Improving Dispersion of Carbon Nanotubes in Epoxy Resins. J. Mater. Sci. 2013, 48 (3), 1005–1013. https://doi.org/10.1007/s10853-012-6830-3.(3) Ham, S. W.; Hong, H. P.; Kim, J. H.; Min, S. J.; Min, N. K. Effect of Oxygen Plasma Treatment on Carbon Nanotube-Based Sensors. J. Nanosci. Nanotechnol. 2014, 14 (11), 8476–8481. https://doi.org/10.1166/jnn.2014.10007.(4) Hulicova-Jurcakova, D.; Seredych, M.; Lu, G. Q.; Bandosz, T. J. Combined Effect of Nitrogen- and Oxygen-Containing Functional Groups of Microporous Activated Carbon on Its Electrochemical Performance in Supercapacitors. Adv. Funct. Mater. 2009, 19 (3), 438–447. https://doi.org/10.1002/adfm.200801236.(5) Li, L.; Liu, E.; Shen, H.; Yang, Y.; Huang, Z.; Xiang, X.; Tian, Y. Charge Storage Performance of Doped Carbons Prepared from Polyaniline for Supercapacitors. J. Solid State Electrochem. 2011, 15 (1), 175–182. https://doi.org/10.1007/s10008-010-1087-8. Figure 1

Effects of Oxygen Plasma Treatments on Surface Functional Groups and Shear Strength of Carbon Fiber Composites

The morphology and chemical function of surfaces strongly influence adhesion at interfaces within carbon fiber composites (i.e., carbon fiber-reinforced polymer) and the mechanical strength of the ...

Effect of oxygen plasma treatment on the nanofiltration performance of reduced graphene oxide/cellulose nanofiber composite membranes

Graphene based nanosheets have been widely used as building blocks for fabrication of superior separation membrane for water processing. In particular, membranes made of reduced graphene oxide (rGO) show better stability compared with graphene oxide (GO). However, densely stacked of rGO often results in low water flux. In this study, cellulose nanofibers (CNFs) were incorporated into the rGO laminates by vacuum filtration of dilute GO/CNF solution and thermal reduction at 150 °C for 1.5 h. The resulting rGO/CNF membrane was treated with oxygen plasma for 1–4 min to create nanopores on the membrane surface for the purpose of enhancing nanofiltration performance. The results showed that the optimum membrane performance was obtained by using the equal amount of GO (31.83 mg m-2) and CNFs accompanied by 3 min of plasma treatment, exhibiting a pure water permeance of 37.2 ± 3.9 L m-2 h-1 bar-1 maintaining a rejection above 90% for Acid Fuchsin (1.2×1.1 nm), Rose Bengal (1.5×1.2 nm) and Brilliant Blue (2.2×1.7 nm).

Enhancement of photodegradation efficiency of PVA/TiO2 nanofiber composites via plasma treatment

Anatase titanium dioxide (TiO2) nanoparticles (NPs) embedded in poly(vinyl alcohol) (PVA) nanofibers were fabricated for the photodegradation of methylene blue (MB) as the test analyte. 1 wt% TiO2 NPs were dispersed in 12 wt% PVA solution prior to electrospinning to form the nanofibers. Raman spectroscopy implied the incorporation of the NPs into the nanofibers without significant change in the chemical structure of either TiO2 or PVA. Scanning electron microscopy, energy dispersive x-ray spectroscopy, and transmission electron microscopy revealed smooth, bead-free, and continuous nanofibers, uniform NP distribution, and negligible NP agglomeration, respectively. The effect of oxygen plasma treatment on the photodegradation efficiency of the PVA/TiO2 was also investigated. Photodegradation of MB exhibited up to 30% increase in degradation efficiency using the plasma-treated PVA/TiO2 nanofiber mats. The partially exposed immobilized TiO2 NPs became more photocatalytically active while being supported by PVA nanofibers. Immobilization of TiO2 NPs would allow reusability thereby extending its service life ideal for environmental applications.

Hybrid Plasma-Liquid Treatment of Carbon Nanotubes for Application in Direct Absorption Solar Thermal Collectors

Awareness of the environmental pollution caused by fossil fuels and the ever-increasing demand for energy has driven research focussed on zero-carbon renewable energy sources. Conscious of this, direct absorption solar thermal collectors are gaining prominence, both for domestic heating and steam generation. Carbon nanotubes (CNTs) have been investigated as an additive to take advantage of the near blackbody absorption and high thermal conductivity to improve system efficiency. Critical to the success of the additive nanoparticles is the stability in the fluid, however, due to their high surface energy CNTs tend to agglomerate which can limit the efficacy of their integration into real-world products. Covalent functionalization of the CNT sidewalls with oxygen-based or nitrogen-based functional groups is one of the most popular techniques to modify the surface energy of the CNTs.1 As an alternative to the harsh chemicals used by traditional chemical functionalisation, plasma-based surface treatments can be used with great efficacy and reduced reaction times.In this work, macroscopic ribbon-like assemblies of carbon nanotubes are functionalized using a simple direct current-based plasma-liquid system. This system utilizes the plasma-generated species in a fluid of 10 %vol ethanol in water, with or without a nitrogen precursor, for the oxygen and/or nitrogen functionalisation of the carbon nanotube assembly. For this treatment, a ribbon-like piece of CNT was used as the anode and a helium plasma discharge triggered by applying 10 mA and 1 - 1.6 kV to act as the cathode. The plasma-generated species are then expected to migrate towards the CNTs and functionalisation the sidewalls.The oxygen content is shown to be increased by between 50 % and 200 % when the treatment solution of 10 %vol ethanol is used in the ribbon electrode configuration. When ethylenediamine is added as a nitrogen precursor, the atomic concentration of nitrogen reaches 23 % in the ribbon electrode configuration, with amine groups, pyrrolic groups and graphitic nitrogen observed in the x-ray photoelectron spectra. This nitrogen content is unmatched in quantity when compared to either a simple soaking procedure or an electrolysis process with a platinum foil replacing the plasma as the counter-electrode. This demonstrates that the plasma either directly or indirectly, by means of plasma-generated species, facilitates and enhances the availability of nitrogen from the ethylenediamine precursor. The potential plasma-induced chemical pathways which lead to the functionalization of the CNTs are also investigated and discussed.In the application of a DASC system, it is found that the covalent functionalisation provided by the plasma-liquid system enhances the stability of the CNT-EG nanofluid, with the oxygen-functionalized samples producing the most stable nanofluids. This functionalization method generates interest for a broader range of applications including mechanically superior advanced composites,2 more sensitive gas sensors,3 enhanced energy storage materials4 or ultra-conductive fibres.5 References (1) Mallakpour, S.; Soltanian, S. Surface Functionalization of Carbon Nanotubes: Fabrication and Applications. RSC Adv. 2016, 6 (111), 109916–109935.(2) Williams, J.; Broughton, W.; Koukoulas, T.; Rahatekar, S. S. Plasma Treatment as a Method for Functionalising and Improving Dispersion of Carbon Nanotubes in Epoxy Resins. J. Mater. Sci. 2013, 48 (3), 1005–1013.(3) Ham, S. W.; Hong, H. P.; Kim, J. H.; Min, S. J.; Min, N. K. Effect of Oxygen Plasma Treatment on Carbon Nanotube-Based Sensors. J. Nanosci. Nanotechnol. 2014, 14 (11), 8476–8481.(4) Hulicova-Jurcakova, D.; Seredych, M.; Lu, G. Q.; Bandosz, T. J. Combined Effect of Nitrogen- and Oxygen-Containing Functional Groups of Microporous Activated Carbon on Its Electrochemical Performance in Supercapacitors. Adv. Funct. Mater. 2009, 19 (3), 438–447.(5) Li, L.; Liu, E.; Shen, H.; Yang, Y.; Huang, Z.; Xiang, X.; Tian, Y. Charge Storage Performance of Doped Carbons Prepared from Polyaniline for Supercapacitors. J. Solid State Electrochem. 2011, 15 (1), 175–182. Figure 1

Plasma activation and chitosan attachment on cotton and wool for improvement of dyeability and fastness properties

PurposeThe dyeing of cellulosic and proteinous fibers with natural and synthetic colorants usually needs large amounts of metal salts to promote the dyeing procedure. To get rid of the necessity to use metal salts, plasma treatment and subsequent attachment of chitosan biopolymer were considered as green processes for surface functionalization of wool and cotton. The purpose of this paper is to investigate the effect of oxygen plasma treatment and attachment of chitosan on the dyeability of wool and cotton fabrics using walnut and weld as model natural dyes, as well as C.I. reactive blue 50 and C.I. acid blue 92 as model synthetic dyes.Design/methodology/approachWool and cotton fabrics were modified with oxygen plasma and coated with chitosan solution. The un-modified and modified samples were dyed with the above-mentioned dyes under constant conditions. The color strength, color coordinates and fastness properties of the dyed samples were determined and compared.FindingsThe results showed that oxygen plasma treatment could improve the dyeability and fastness properties of wool and cotton fibers when dyed with all of the above-mentioned dyes. Attachment of chitosan to the plasma-treated samples significantly improved the dyeability of wool and cotton fibers with walnut, acid and reactive dyes. The fastness properties of the dyed samples were enhanced by plasma treatment and chitosan coating.Originality/valueThis study uses plasma treatment as an environmentally friendly pre-treatment for attachment of chitosan on wool and cotton. This process improved the dyeing properties of both fibers. The use of metal salts in not needed for dyeing of wool and cotton according to the investigated process.

Bacterial attachment to oxygen-functionalized graphenic surfaces.

In this work we have investigated the effect of oxygen plasma treatment of graphenic surfaces and the introduction of functional groups on changes in work function, wettability, surface free energy and bacterial adhesion. The plasma parameters were adjusted (generator power: <60W, exposure time: <20min) to limit the modifications to the surface without changing the bulk structure. The parent and modified graphenic surfaces were thoroughly characterized by μRaman spectroscopy, thermogravimetry, scanning electron microscopy, contact angle, X-ray photoelectron spectroscopy, work function and microbiological tests. It was found that even the short time of plasma modification results in a significant increase in work function, surface free energy and hydrophilicity. The changes in surface chemistry stimulate also substantial changes in bacterial adhesion. The strong relationship between work function and adhesion of bacteria was observed for all the investigated strains (Staphylococcus epidermidis, Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli) whereas the bacterial colonization trend correlates with the bacterial zeta potential. The bacteria-graphenic surface interaction is discussed in terms of total interaction energy. The results point out the work function lowering of the graphenic biomaterial surface as an effective strategy for the infection risk limitation.

Study of oxygen plasma induced modulation of photoconductivity in MoS2 field effect transistor

Abstract We studied the effect of oxygen plasma treatment on the drain current and photoconductivity of the two dimensional few-layers MoS2 based field-effect transistors (FETs). It was observed that the oxygen plasma can reduce the photoconductivity of MoS2 channel along with variation in the current characteristics. This study shows the contribution of mild oxygen plasma to modulate the photoconductivity of the MoS2 FETs which can have potential in optoelectronic detectors and sensors applications.

BACTERIAL CELLULOSE MEMBRANES WITH PLASMA‐MODIFIED SURFACES FOR TISSUE ENGINEERING APPLICATIONS

Bacterial cellulose (BC) is a promising biomaterial notable for its features such as strength, hydrophilicity, and biocompatibility, which enable it to be used as implants and scaffolds in tissue engineering. However, its topography does not present the ideal characteristics for cell attachment and development, so surface modifications are required in order to improve the cellular response. The objective of this study was to analyze the effects of oxygen plasma treatment applied to bacterial cellulose (BC) for 2.5 and 5 minutes, together with its effects on cell behavior during 21 days of culture. Osteo‐1 cells were cultured in the absence and presence of BC, at an initial density (day 0) of 1000 cells per 200 μL of osteogenic medium (DMEM + FBS + ascorbic acid + dexamethasone + β‐glycerophosphate), in 48‐well culture plates, for 7, 14, and 21 days, with exchange of the medium every 72 h. Cell counting was performed with a Bio‐Rad TC20™ cell counter, viability was analyzed using the MTT test, and mineralization was quantified by the Alizarin Red test. Alkaline phosphatase (AP) in the culture medium was measured using a commercial LabTest kit. Statistical analysis of the data was performed using ANOVA and Fisher’s test for multiple comparisons. Alkaline phosphatase results: Higher AP was observed for the group with application of the plasma to the BC for 5 minutes, while no statistically significant differences were found among the groups without treatment, treatment for 2.5 minutes, or in the absence of BC, as well as between the days of culture. Culture time effects: Higher cell counts were obtained for the control group without BC and the group with untreated BC. The highest cell counts were observed at 14 and 21 days of culture, with no statistically significant differences among the means. Mineralization and cell viability: The highest responses for mineralization and viability were observed at 7 days of culture, followed by decreases at 14 and 21 days. The results were indicative of changes on the bacterial cellulose surface caused by the oxygen plasma treatment, which influenced the cell features. The findings indicated that plasma treatment for up to 5 minutes changed the topography of the surface, leading to better conditions for cell differentiation and development from Osteo‐1 to osteoblast, as indicated by the higher AP concentration for this group. The treatment for 5 minutes led to enhanced cellular responses on the bacterial cellulose, contributing to better cell development.Support or Funding InformationFundingFAPESP (grant #2018/14840‐4).

Single-particle study: effects of oxygen plasma treatment on structural and spectral changes of anisotropic gold nanorods.

Oxygen plasma treatment is a common method for removing the surfactant capping material from gold nanoparticles, improving their functionalization and lowering their cytotoxicity for biological studies. This single-particle study investigates the effects of oxygen plasma treatment on the structural and localized surface plasmon resonance (LSPR) spectral variations of anisotropic gold nanorods (AuNRs). Single AuNRs subjected to different plasma treatment times were characterized by scanning electron microscopy and dark-field microscopy. The AuNR length was a gradually decreasing function of plasma treatment time. After 120 s of plasma treatment, the aspect ratio of the AuNRs was reduced by a major structural deformation. Furthermore, increasing the plasma treatment time gradually broadened the LSPR linewidth of the single AuNRs. This trend was attributed to the decreased aspect ratio and the increased plasmon damping. These results provide vital and fundamental information on the relationship among plasma treatment time, structural change, and LSPR damping at the single-particle level.

氧等离子体处理对GaAs表面单层自组装SiO2纳米球薄膜的影响

氧等离子体处理对GaAs表面单层自组装SiO2纳米球薄膜的影响