Nanoparticle Films Research Articles

Simultaneous Li-Doping and Formation of SnO2-Based Composites with TiO2: Applications for Perovskite Solar Cells.

Tin oxide (SnO2) has been recognized as one of the beneficial components in the electron transport layer (ETL) of lead-halide perovskite solar cells (PSCs) due to its high electron mobility. The SnO2-based thin film serves for electron extraction and transport in the device, induced by light absorption at the perovskite layer. The focus of this paper is on the heat treatment of a nanoaggregate layer of single-nanometer-scale SnO2 particles in combination with another metal-dopant precursor to develop a new process for ETL in PSCs. The combined precursor solution of Li chloride and titanium(IV) isopropoxide (TTIP) was deposited onto the SnO2 layer. We varied the heat treatment conditions of the spin-coated films comprising double layers, i.e., an Li/TTIP precursor layer and SnO2 nanoparticle layer, to understand the effects of nanoparticle interconnection via sintering and the mixing ratio of the Li-dopant on the photovoltaic performance. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) measurements of the sintered nanoparticles suggested that an Li-doped solid solution of SnO2 with a small amount of TiO2 nanoparticles formed via heating. Interestingly, the bandgap of the Li-doped ETL samples was estimated to be 3.45 eV, indicating a narrower bandgap as compared to that of pure SnO2. This observation also supported the formation of an SnO2/TiO2 solid solution in the ETL. The utilization of such a nanoparticulate SnO2 film in combination with an Li/TTIP precursor could offer a new approach as an alternative to conventional SnO2 electron transport layers for optimizing the performance of lead-halide perovskite solar cells.

Facile synthesis of Cu-Sn nanoparticle film and its bonding mechanism for power electronic packaging

The Cu-Sn full intermetallic compound is a promising high-temperature electronic packaging material, while its preparation is usually time-consuming. In this work, a novel dual-beam laser co-deposition method was proposed to prepare Cu-Sn nanoparticle film for power electronic packaging with high bonding efficiency. Various Cu-Sn contents were prepared to reveal the bonding mechanism of the full intermetallic compound structure. The results show that joints with a Cu content ranging from 20 wt% to 80 wt% could form full intermetallic compounds within 2 min with the shear strength reaching 120 MPa. Specifically, Cu6Sn5, 'island-like' Cu3Sn, and sintered Cu generated successively in the bondline center with the increasing Cu content. All failures occurred within the bondline indicating a higher interface bonding quality, while the 'island-like' Cu3Sn enhanced the shear strength. This die attach process is compatible with current commercial SiC die attach process with lower material cost as well as high efficiency, enabling the Cu-Sn nanoparticle film to be a promising material for high-reliability power electronic packaging.

Quantitative analysis model based on surface‐enhanced Raman spectroscopy of malachite green adsorbed on gold nanoparticles film substrates

AbstractIn order to investigate the adsorption process of malachite green (MG) on gold nanoparticles, a simple gold nanoparticles‐assembled film was prepared as a substrate of surface‐enhanced Raman spectroscopy (SERS), and it was soaked in MG solutions of different concentrations. The kinetic adsorption process was investigated by SERS method and density functional theoretical calculations. When saturated adsorption was achieved, the relationship between the characteristic SERS band signal intensity and the logarithm of solution concentration of MG was consistent with Temkin adsorption isotherm model, where the R2 value was greater than 0.995, and the linear range was 1 × 10−3–1 × 10−7 M. Finally, a SERS quantitative analysis model of the relationship between the adsorption properties of surface species and the bulk concentration was established. According to the electrostatic interaction and co‐adsorption, we proposed the surface adsorption configurations and adsorption process of MG on the nanostructured gold films.

In-situ self-assembly growth of controllable gold nanoparticles film

Because of the strong light absorption and/or scattering, nano scaled gold has many favorable optic and electric properties. With the continuous miniaturization of nano photoelectronic devices and nano electromechanical systems, there is an urgent demand for controllable and tailored gold nanoparticles film with excellent performance. Here, a modified HAuCl4-NaOH-CTAB (cetyltrimethylammonium bromide) aqueous solution system was utilized to self-assembly synthesize gold nanofilm on glass substrates. The high concentration NaOH is not only reducing Au3+ to Au0, but facilitating interfacial assembly of gold nanostructure at liquid–solid interface via etching glass surface. Based on this growth kinetic, the gradient, well-designed and in-situ growing gold nanoparticles film can be achieved on any SiO2 contained substrates by controlling the growth time in the reaction system. Furthermore, the in-situ self-assembled gold nanoparticles film can be act as plasmon substrates for surface-enhanced Raman scattering (SERS) or plasmonic enhanced semiconductor lasing, even gold electrodes.

Reconfigurable intelligent surface and switchable electromagnetic interference shield based on dynamically adjustable composite film of cellulose nanofibers and VO2 nanoparticles

The emerging fields of 5G and 6G telecommunication networks, Internet of Things, and artificial intelligence have intensified the demand for green nanostructured materials with adjustable and intelligent features that respond to external stimuli. By leveraging the insulator-to-metal transition of VO2 nanoparticles, responsive composite films were developed by integrating these nanoparticles within a biopolymeric network of cationic cellulose nanofibers (CNF+). These films exhibit a reversible change in GHz permittivity upon exposure to thermal or optical stimuli, facilitating dynamic control of their electrical properties. The layered structure of the films further enhances their robustness, featuring a VO2 nanoparticle core encased within CNF+ layers. This design not only strengthens the structure but also significantly boosts light-induced conductivity, particularly in layered variant, underscoring its potential in optoelectronic applications. Simulation studies reveal that the nonuniform, reconfigurable intelligent surface (RIS) of the developed mixed film adeptly manipulates incident electromagnetic waves, making it suitable for 5G/6G wireless signals. Conversely, the layered film serves as a switchable electromagnetic interference (EMI) shield, demonstrating notable differences in shielding efficiency between its hot and cold states. Consequently, CNF+/VO2 composite films designed in this work emerge as a versatile, adaptable platform for intelligent electronics, particularly in the realm of 5G/6G wireless communications.

Evaluating the ATR-SEIRAS Performance of Electrodeposited Copper CO2 Reduction Catalysts using a Flow-Through Spectroelectrochemical Cell

The ATR-SEIRAS (attenuated total reflection surface enhanced infrared absorption spectroscopy) activity of electrodeposited Cu nanoparticles on indium tin oxide (ITO)-modified Si internal reflection elements is reported. The solution in the cell is easily, and repeatedly, exchanged between a copper deposition bath and a solution containing 4-methoxypyridine through the use of a flow-through spectroelectrochemical cell. 4-methoxypyridine is a convenient SEIRAS probe molecule exhibiting potential dependent adsorption/desorption on the copper surface. Successive amounts of copper are deposited and then evaluated for electrochemical SEIRAS activity without the need to expose the Cu surface to ambient conditions. It is found that copper deposition charge densities of approximately 60 mC cm-2 exhibit the largest amplitude and most symmetric IR absorption peaks of the investigated electrodeposition conditions. SEM images of the different Cu charge density films are correlated with the SEIRAS results and establish that close-packed two-dimensional, percolated arrays of oblate, ellipsoidal Cu nanoparticles are responsible for ideal SEIRAS performance and three-dimensional aggregates of larger particles should be avoided. Textured films of Cu nanoparticles are used to determine the adsorbed species present on the copper surface during CO2 electroreduction at low overpotentials. Evidence of adsorbed CO and COH is found at lower overpotentials than those described in previous reports.

Highly stable and efficient gold nanoparticles films facilitated by thiourea for catalytic reduction of nitrophenol in water

Water pollution from nitrophenol, a common nitrogen-containing aromatic pollutant, is becoming increasingly significant. Making the conversion of nitrophenol to the less toxic and more easily biodegradable aminophenol is a promising strategy to treat industrial wastewater. A simple and efficient method for treating nitrophenol was investigated using gold nanoparticles (AuNPs) with thiourea and fabricating AuNPs films via filtration for the first time. The prepared AuNPs film with nanoporous structure exhibits good structural stability and excellent catalytic activity. The results show that the optimal concentration of adding thiourea is 20 μg/mL, and the optimal concentration of adding NaBH4 is 1000 mM. After treatment with 20.0 μg/mL thiourea, the prepared AuNPs film catalyzes the degradation of 1.0 mM 2-nitrophenol to 2-aminophenol in just 150 sec. The AuNPs film provides a high density of active sites at the interface, and its stable nanoporous structure brings the substrate nitrophenol closer to the active center, thus enhancing the efficiency of catalytic reduction. Besides, the AuNPs films treated with thiourea still maintained good catalytic performance after seven cycles of catalysis and the catalytic efficiency is still as high as 90%. The thiourea-treated AuNPs film sets a precedent for the innovation of novel catalysts that is a very promising industrial strategy for reducing nitrophenol to aminophenol, offering significant economic advantages.

Tuning the Interfacial Chemistry of Nanoparticle Assemblies via Spin‐Coating: From Single Sensors to Monolithic Sensor Arrays

AbstractSensor arrays based on gold nanoparticle (GNP) films are promising candidates for numerous applications, including medical diagnosis and health monitoring. Their economic fabrication, however, remains challenging. This study presents a facile route to GNP chemiresistors with tunable properties via layer‐by‐layer spin‐coating (LbL‐SC). Key steps involve the alternating deposition of dodecylamine‐stabilized GNPs and mixtures of monothiols (MTs) with 1,9‐nonanedithiol (9DT). The 9DT molecules serve to reinforce the growing film via GNP cross‐linking while the MT ligands are used to tune the interfacial chemistry of the GNP assembly. Hence, by employing differently functionalized MTs the sensors' chemical selectivity can easily be adjusted. Further, by varying the MT‐9DT ratio and adjusting the size of the MT ligands the sensitivity can be tuned along with the conductivity and optical properties of the films. In general, decreasing the 9DT fraction significantly enhances the sensitivity while the response isotherms change from Langmuir‐Henry to Henry type. Finally, the cross‐linked GNP films are robust enough to be patterned via photolithography. Hence, this study demonstrates the fabrication and application of monolithic sensor arrays. Different features of the responses to numerous analytes are used as input data for linear discriminant analyses (LDA), revealing that very similar analytes can be distinguished.

Development of PVA/sodium alginate incorporated with histidine capped silver nanoparticles for food packaging application

AbstractPackaging is a growing field of interest, and the use of nanotechnology is accelerating its expansion. The study reports the fabrication of poly(vinyl alcohol) (PVA) blended sodium alginate (SA) and incorporated with different ratios of histidine‐capped silver (H‐AgNPs) nanoparticle films. Fabrication of PVA/SA/H‐AgNPs films was confirmed with the surface plasmon resonance (SPR) band denoted AgNPs presence between 400 and 420 nm measured by UV–Vis absorption spectroscopy. The characteristics of the polymeric biocomposite films were significantly altered by different ratios of AgNPs. The interaction of PVA/SA and PVA/SA with AgNPs was analyzed by using FT‐IR analysis. The degree of crystallinity was increased upon increasing the concentration of H‐AgNPs as confirmed by XRD measurements. The homogeneity of dispersion and surface morphology of samples were studied by FESEM. The addition of H‐AgNPs in the polymeric film increased the surface roughness of the polymeric film confirmed by AFM analysis. The contact angle of the PVA/SA blend matrix was observed to be 46.97°, and with the incorporation of AgNPs ranging from 3%, 5%, and 7% to the blend matrix, the contact angle of the nanocomposite films in increasing hydrophobic order was 60.53°, 83.57°, and 96.20°, respectively. The incorporation of AgNPs also demonstrates that the PVA/SA blend matrix has desirable thermal stability. The improved qualities were due to H bonding between PVA, SA, and H‐AgNPs, in which molecules contact strongly with one another. Furthermore, the PVA/SA/H‐AgNPs showed significant antibacterial activity against both Gram‐positive (G+) strains (Staphylococcus aureus) and Gram‐negative (G−) strains (Escherichia coli) bacterial infections. The findings of this research indicate that the PVA/SA/H‐AgNPs fabricated composite films considerable for applications in food packaging.

Characterization of banana powder-based film reinforced with CNF and Bio-mediated ZnO nanoparticles for potential food applications

The formulation of a multifunctional nanocomposite packaging material with potential against agents of food deterioration, such as free radicals and microorganisms, has emerged as a solution for shelf-life extension and food security. This study developed banana powder (BP) film infused with cellulose nanofiber (CNF) and ZnO-PPW and ZnO-PSW nanoparticles (NPs) at different concentrations for food applications. The BP/CNF/ZnO films were characterized using UV–vis spectroscopy, XRD, FT-IR, and SEM techniques. The analyses confirmed the successful infusion of ZnO NPs into the BP/CNF matrix, leading to significant changes (p < 0.05) in color and appearance, enhanced UV–vis barrier properties, and increased thickness and flexibility of the films. Furthermore, the presence of ZnO in the base matrix influenced the moisture content (19%–29%), film solubility (68%–74%), and oil permeability significantly more than the control BP/CNF film. Adding ZnO significantly improved the UV barrier properties compared to the control. The nanocomposite BP/CNF/ZnO films demonstrated concentration-based antioxidant and good antimicrobial activity against five selected food pathogens (Escherichia coli, Enterococcus faecalis, Listeria monocytogenes and Staphylococcus aureus). Similarly, good antioxidant properties were reported in different assays, proving superior to the control BP/CNF. These key findings, especially those of the BP/CNF/ + 0.6% ZnO NPs films, showed that these films possess great potential for application as food packaging materials with antioxidant and antimicrobial properties.

Harmonic Generation up to Fifth Order from Al/Au/CuS Nanoparticle Films.

Dual heterostructures integrating noble-metal and copper chalcogenide nanoparticles have attracted a great deal of attention in nonlinear optics, because coupling of their localized surface plasmon resonances (LSPRs) substantially enhances light-matter interactions through local-field effects. Previously, enhanced cascaded third-harmonic generation was demonstrated in Au/CuS heterostructures mediated by harmonically coupled surface plasmon resonances. This suggests a promising approach for extending nonlinear enhancement to higher harmonics by adding an additional nanoparticulate material with higher-frequency harmonic resonances to the hybrid films. Here we report the first observation of enhanced cascaded fourth- and fifth-harmonic generation in Al/Au/CuS driven by coupled LSPRs at the fundamental (1050 nm), second harmonic (525 nm), and third harmonic (350 nm) of the pump frequency. An analytical model based on incoherent dipole-dipole interactions among plasmonic nanoparticles accounts for the observed enhancements. The results suggest a novel design for efficiently generating higher harmonics in resonant plasmonic structures by means of multiple sum-frequency cascades.

Plasmonic Properties of Self-Assembled Gold Nanocrescents: Implications for Chemical Sensing.

A bottom-up approach, the Langmuir-Blodgett technique, is used for the preparation of composite thin films of gold nanoparticles and polymers: poly(styrene-b-2-vinylpyridine), poly-2-vinylpyridine, and polystyrene. The self-assembly of poly(styrene-b-2-vinylpyridine) at the air-water interface leads to the formation of surface micelles, which serve as a template for the organization of gold nanoparticles into ring assemblies. By using poly-2-vinylpyridine in conjunction with low surface pressure, the distance between nanostructures can be increased, allowing for optical characterization of single nanostructures. Once deposited on a solid substrate, the preorganized gold nanoparticles are subjected to further growth by the reduction of additional gold, leading to a variety of nanostructures which can be divided into two categories: nanocrescents and circular arrays of nanoparticles. The optical properties of individual structures are investigated by optical dark-field spectroscopy and numerical calculations. The plasmonic behavior of the nanostructures is elucidated through the correlation of optical properties with structural features and the identification of dominant plasmon modes. Being based on a self-assembly approach, the reported method allows for the formation of interesting plasmonic materials under ambient conditions, at a relatively large scale, and at low cost. These attributes, in addition to the resonances located in the near-infrared region of the spectrum, make nanocrescents candidates for biological and chemical sensing.

Unsupported Pt Nanoparticles: Synthesis, Deactivation, and Hydrogen Electrocatalysis in Unpurified Electrolytes

Platinum is ubiquitous in electrochemical catalysis owing to its ability to accelerate redox reactions involving surface-bound hydrogen and oxygen. Accordingly, Pt is used as a calibration standard and activity benchmark against which novel electrocatalysts are compared. These measurements are often executed in unpurified, reagent grade electrolytes where Pt is also susceptible to deactivation by several routes. This constitutes a challenge where the ease of making measurements with Pt-based catalysts must be balanced against the difficulty of obtaining accurate and consistent results. We report herein a synthetic procedure for unsupported Pt nanoparticles that uses readily available reagents and laboratory apparatus, with the goal of making high-quality control experiments in electrocatalysis as accessible as possible. We also identified conditions under which these particles deactivate in unpurified aqueous acid and base and differentiated between mechanisms involving catalyst poisoning, which dominates at more negative applied potentials, and particle growth, which dominates at positive potentials where Pt-oxide species are produced. Finally, we demonstrated that unsupported Pt nanoparticle films can be used to good effect for reference electrode calibration and benchmarking of hydrogen evolution/oxidation electrocatalysts, even in unpurified electrolytes, provided steps are taken to minimize the impact of deactivation.

Vibration Sensors on Flexible Substrates Based on Nanoparticle Films Grown by Physical Vapor Deposition.

Flexible electronics have gained a lot of attention in recent years due to their compatibility with soft robotics, artificial arms, and many other applications. Meanwhile, the detection of acoustic frequencies is a very useful tool for applications ranging from voice recognition to machine condition monitoring. In this work, the dynamic response of Pt nanoparticles (Pt NPs)-based strain sensors on flexible substrates is investigated. the nanoparticles were grown in a vacuum by magnetron-sputtering inert-gas condensation. Nanoparticle sensors made on cracked alumina deposited by atomic layer deposition on the flexible substrate and reference nanoparticle sensors, without the alumina layer, were first characterized by their response to strain. The sensors were then characterized by their dynamic response to acoustic frequency vibrations between 20 Hz and 6250 Hz. The results show that alumina sensors outperformed the reference sensors in terms of voltage amplitude. Sensors on the alumina layer could accurately detect frequencies up to 6250 Hz, compared with the reference sensors, which were sensitive to frequencies up to 4250 Hz, while they could distinguish between two neighboring frequencies with a difference of no more than 2 Hz.

Preparation of Ag-Cu nanoparticle film using a dual-beam pulsed laser deposition for power electronic packaging

Ag-Cu nanoparticles, integrating the advantages of Ag and Cu, are promising materials for power electronic packaging. In this work, a novel dual-beam pulsed laser deposition method was proposed to prepare an Ag-Cu nanoparticle film with various component ratios and used for die attach at low temperatures. The as-deposited Ag-Cu nanoparticle film was mainly composed of Ag-Cu solid solution, Ag element, and Cu element, and most of the nanoparticles were in the alloying state. The Ag-Cu sintered joint presented a dense microstructure with 10.8% porosity, and the shear strength of Ag-Cu sintered joints could reach 60 MPa at 250 °C. The sintered joint porosity increased as more Cu were added in the Ag-Cu nanoparticle film, resulting in a decrease in the interfacial connection ratio. The fracture mode of sintered joints gradually changed from the sintered layer to the mixed sintered layer and interface fracture. The dual-beam pulsed laser deposition method could guide in designing the component ratios of bimetallic nanoparticles.

SERS-based AI diagnosis of lung and gastric cancer via exhaled breath

Distinct diagnosis between Lung cancer (LC) and gastric cancer (GC) according to the same biomarkers (e.g. aldehydes) in exhaled breath based on surface-enhanced Raman spectroscopy (SERS) remains a challenge in current studies. Here, an accurate diagnosis of LC and GC is demonstrated, using artificial intelligence technologies (AI) based on SERS spectrum of exhaled breath in plasmonic metal organic frameworks nanoparticle (PMN) film. In the PMN film with optimal structure parameters, 1780 SERS spectra are collected, in which 940 spectra come from healthy people (n = 49), another 440 come from LC patients (n = 22) and the rest 400 come from GC patients (n = 8). The SERS spectra are trained through artificial neural network (ANN) model with the deep learning (DL) algorithm, and the result exhibits a good identification accuracy of LC and GC with an accuracy over 89 %. Furthermore, combined with information of SERS peaks, the data mining in ANN model is successfully employed to explore the subtle compositional difference in exhaled breath from healthy people (H) and L/GC patients. This work achieves excellent noninvasive diagnosis of multiple cancer diseases in breath analysis and provides a new avenue to explore the feature of disease based on SERS spectrum.

CdSe nanostructured thin film by electrophoretic deposition for quantum dots sensitized solar cell.

Cadmium selenide (CdSe) quantum dots (QDs) with different size, 2.5 and 3.2 nm, were successfully deposited on mesoporous titanium dioxide (TiO2) (Degussa-P25) nanostructures by electrophoretic deposition method (EPD) at the applied voltage 100 V for 120 s deposition time. In this study, the morphology of CdSe films deposited by EPD and the performance of the film when assembled into a solar cell were investigated. From the field emission scanning electron microscopy cross-section, the thickness of the CdSe nanoparticles with size 2.5 nm films were 3.4 and 3.0μm for CdSe 3.2 nm nanoparticles film. The structure of 2.5 nm is denser than compare of 3.2 nm CdSe nanoparticles. From UV visible spectroscopy, the band gap calculated for 2.5 nm CdSe nanoparticles is 2.28 eV and for 3.2 nm is 2.12 eV. Photovoltaic characterization was performed under an illumination of 100 mW cm-2. A photovoltaic conversion efficiency of 1.81% was obtained for 2.5 nm CdSe and 2.1% was obtained for 3.2 nm CdSe nanoparticles. This result shows that the photovoltaic efficiency is dependent on CdSe nanoparticle size.

Multiscale identification of the inorganic shell of core (Co)/shell‐assembled nanoparticles

AbstractCore (Co)/shell (Co‐oxide) nanoparticles assembly exhibits interesting magnetic properties that depend on the inorganic shell characteristic (composition and crystalline structure). Assemblies of pure and partially oxidized cobalt (core/shell) nanoparticles, ~9 nm in diameter, were prepared and analyzed by techniques probing the matter at macroscale to nanoscale: UV–visible‐near‐infrared (NIR) transmission, FTIR, Raman microspectroscopy, and transmission electron microscopy. Attention is paid to compare nonoxidized and (partially) oxidized Co nanoparticles, coated with lauric acid as stabilizing agent (ligands). The approximately 1 nm disordered inorganic coating is perfectly detected by transmission electron microscopy, UV–visible–NIR, infrared, and Raman spectroscopy. The Raman spectrum is sensitive to laser wavelength and power due to the local heating induced by the laser, which modifies the interaction between the organic chains and the nanoparticle inorganic shell. For comparison, nanoparticle films were analyzed under heating from room temperature to 300°C. The “fusion” (dynamic disorder) of lauric (dodecanoic) chains is observed concomitantly with the merging of very low wavenumber Lambs' modes into a Rayleigh wing, which is consistent with an increase in the topological nanoparticle disorder. Hydroxylation or water adsorption is observed for Co film. The UV–visible–NIR and Raman spectra of the Co‐oxide shell do not correspond to that of CoO (rock salt) nor to that of Co3O4 (spinel) but has some similarity to that of 2D delafossite (CoOOH) phase.

Ionic Liquid-Assisted Thermal Evaporation of Bimetallic Ag-Au Nanoparticle Films as a Highly Reproducible SERS Substrate for Sensitive Nanoplastic Detection in Complex Environments.

Nanoplastic particles are emerging as an important class of environmental pollutants in the atmosphere that have adverse effects on our ecosystems and human health. While many methods have been developed to quantitatively detect nanoplastics; however, sensitive detection at low concentrations in a complex environment remains elusive. Herein, we demonstrate a greener method to fabricate a surface-enhanced Raman spectroscopy (SERS) substrate consisting of self-assembled plasmonic Ag-Au bimetallic nanoparticle (NP) films for quantitative SERS detection of nanoplastics in complex media. The self-assembly of Ag-Au bimetallic NPs was achieved through thermal evaporation onto a vapor-phase compatible ionic liquid based on deep eutectic solvent over the growth substrate. The finite-difference time-domain simulation revealed that the localized field enhancement is strong in the gaps, which generate uniform SERS "hotspots" in the obtained substrate. Benefiting from highly accessible SERS "hotspots" at the gaps, the SERS substrate exhibits excellent sensitivity for detecting crystal violet with a limit of detection (LOD) as low as 10-14 M and excellent reproducibility (RSD of 5.8%). The SERS substrate is capable of detecting PET nanoplastics with LOD as low as 1 μg/mL and about 100 μg/mL in real samples such as tap water, lake water, diluted milk, and wine. Moreover, we also validated the feasibility of the designed SERS substrate for the practical detection of PET nanoplastics collected from commercial drinking water bottles, and it showed great potential applications for sensitive detection in actual environments.

Gas-Phase Fabrication and Photocatalytic Activity of TiO2 and TiO2-CuO Nanoparticulate Thin Films.

CuO-loaded TiO2 nanomaterials have applications in pollutant degradation via photocatalysis. However, the existing methods of fabricating these nanomaterials involve liquid-phase processes, which require several steps and typically generate liquid waste. In this study, TiO2 and TiO2-CuO nanoparticulate thin films were successfully fabricated through a one-step gas-phase approach involving a combination of plasma-enhanced chemical vapor deposition and physical vapor deposition. The resulting films consisted of small, spherical TiO2 nanoparticles with observable CuO on the TiO2 surface. Upon annealing in air, the TiO2 nanoparticles were crystallized, and CuO was completely oxidized. The photocatalytic activity of TiO2-CuO/H2O2, when introduced into the rhodamine 6G degradation system, was substantially enhanced under both ultraviolet and visible light irradiation. Moreover, this study highlights the influence of pH on the photocatalytic activity; TiO2-CuO/H2O2 exhibited the highest photocatalytic activity at pH 13, with a reaction rate constant of 0.99 h-1 cm-2 after 180 min of visible light irradiation. These findings could facilitate the development of nanoparticulate thin films for enhanced pollutant degradation in wastewater treatment.