Film Surface Research Articles

Demonstrating the key role of Bacillus in poly lactic acid film degradation through statistical analysis and strain screening.

Plastic films are extensively utilized in agriculture, construction, and manufacturing, with their annual production reaching staggering figures. Addressing the global plastic pollution crisis is imperative. One promising approach is the augmentation of plastic films degradation through microbial agents. Consequently, we undertook composting experiments employing various plastics, including Polyethylene (PE), Poly lactic acid (PLA), and a treatment without plastic films addition (CK), mixed with kitchen waste. Employing bipartite association networks and difference significance analysis methods, we scrutinized the impact of different plastics on the microbial community within the compost piles. There were significant disparities in the microbial community composition among three composting piles. To pinpoint the key microorganisms responsible for PLA degradation, we conducted a comparative analysis of microbial species present on PLA compost piles and PLA film surfaces (PLAS), utilizing variance analysis, co-occurrence network analysis, and Spearman's correlation analysis. Our findings identified Bacillus as the pivotal microorganism involved in PLA degradation. Furthermore, employing function prediction by PICRUSt 2, we identified K00016 as the crucial gene facilitating PLA degradation by Bacillus. Subsequently, employing strain screening techniques, we isolated a highly effective PLA-degrading bacterium, Bacillus amyloliquefaciens strain ML274. The PLA films degradation rate of ML274 reached 3.18%. and other strains was lower than 3.0%. Thus, Bacillus emerges as the primary microorganism driving PLA degradation, emphasizing the significance of focusing on Bacillus genus microorganisms in the development of plastic-degrading bacterial agents for future endeavors.

Characterization of corn starch/chitosan composite films incorporated with amino-, carboxyl- and hydroxyl-terminated hyperbranched dendrimers: A comparative study

Bio-based materials are gaining traction as sustainable plastic replacements, but their performance in terms of mechanics, antibacterial action, and water resistance is often subpar. Our research sought to enhance these attributes by integrating nanoscale dendrimers into a starch/chitosan (SC) matrix. We introduced three varieties of dendrimers—amino-, carboxyl-, and hydroxyl-terminated—at a modest 2.5 % w/w concentration to fabricate NSC, CSC, and HSC films. Comprehensive analyses revealed that the dendrimers fostered intermolecular interactions, prompting an order-disorder shift in the matrix. This interaction textured the film surface and bolstered its thickness, opacity, and tensile strength. The HSC films achieved the highest tensile strength (9.96 MPa) and substantial elongation (254.30 %), attributed to their more disordered structure. The HSC films also showcased enhanced thermal stability and reduced moisture absorption. Notably, NSC films exhibited excellent antibacterial effects against S. aureus and E. coli. The performance improvement of CSC film is mediocre. This study underscores the promise of dendrimer-fortified SC films in the realm of biodegradable materials.

Production of Polyvinyl Alcohol/Amoxicillin – Chitosan/Collagen Hybrid Bilayer Membranes for Regeneration of Gingival Tissues

AbstractPeriodontal diseases, if untreated, can cause gum recession and tooth root exposure, resulting in infection and irreversible damage. Traditional treatments using autologous grafts are painful and often result in postoperative complications. Scaffolds offer a less invasive alternative, promoting cell proliferation and healing without additional surgery, thus enhancing comfort for patients and doctors. This study developed Chitosan (Chit)/Collagen (Col) film surfaces and drug‐loaded Polyvinyl Alcohol (PVA)/Amoxicillin (AMX) nanofibers using solvent casting and electrospinning methods, respectively. The surfaces are characterized by scanning electron microscopy (SEM), mechanical testing, Fourier Transform Infrared Spectroscopy (FTIR), and differential scanning calorimetry (DSC). Biocompatibility and antimicrobial properties are assessed using NIH/3T3 fibroblast cells and bacterial cultures. SEM images confirmed the structural integrity of AMX‐loaded 13% PVA nanofibers, while FTIR analysis validated the compositional integrity of PVA/AMX nanofibers and Chit/Col film hybrid surfaces. Cell studies showed over 90% viability for Chit/Col film + PVA/AMX nanofiber hybrid bilayer membranes, confirming their biocompatibility. The antimicrobial assessment indicated that the Chit/Col film + PVA/AMX (0.2%) nanofiber hybrid bilayer membrane exhibited superior efficacy against Streptococcus mutans. These findings suggest that this hybrid bilayer membrane can enhance cell growth, promote proliferation, and enable controlled drug release, offering significant promise for regeneration of gingival tissues.

Analysis of Water Film Distribution and Aerodynamic Performances of High-Speed Train Under Rainfall Environment

AbstractThe current research on the aerodynamic performance of the train running in rainy weather is primarily concerned with the trajectory of the raindrops and the aerodynamic variation of trains caused by raindrops. In fact, water film will generate on the train body when raindrops hit the train, which interacts with the flow field around the train, and would probably affect the aerodynamic performance of the train. In this paper, based on shear stress transport (SST) k-w turbulence model and Euler-Lagrange discrete phase model, the aerodynamic calculation model of a high-speed train under rainfall environment is established. The LWF (Lagrangian wall film) is used to simulate the water film distribution of the high-speed train under different rainfall intensities, and the aerodynamic performance of the train are studied. The calculation results show that raindrops will gather on the train surface and form water film under rainfall environment. With the extension of rainfall time, the thickness and coverage range of water film expand, and the maximum thickness of water film can reach 4.95 mm under the working conditions in this paper. The average thickness of water film on the train body increases with the rainfall intensity. When the rainfall intensity increases from 100 mm/h to 500 mm/h, the average water film thickness will increase by 3.26 times. The velocity of water film in the streamlined area of head car is larger than that in other areas, and the maximum velocity is 22.14 m/s. Compared with the rainless environment condition, the skin friction coefficient of the high-speed train increases and the average value will increase by 10.74% for a rainfall intensity of 500 mm/h. The positive pressure and resistance coefficient of the head car increase with the rainfall intensity. This research proposes a methodology to systematically analyze the generation of water film on the train surface and its influence on the train aerodynamic performance; the analysis can provide more practical results and can serve as a reference basis for the design and development of high-speed trains.

Dual‐Site Anchors Enabling Vertical Molecular Orientation for Efficient All‐Perovskite Tandem Solar Cells

AbstractAll‐perovskite tandem solar cells (TSCs) are gaining increasing attention due to their potential to surpass the efficiency limit of single‐junction solar cells. However, as the bottom low‐bandgap subcells, tin‐lead (Sn‐Pb) perovskites suffer from severe nonradiative recombination at the interfaces due to their susceptibility to oxidation and poor crystalline morphology. Here a surface modifier 4‐(trifluoromethyl)benzhydrazide (TFH) is reported to construct a reductive chemical environment on the surface of perovskite films and protect them from water and oxygen erosion. TFH anchors onto the Sn‐Pb perovskites in a preferred vertical orientation through dual‐site binding, forming interface dipoles that facilitate charge extraction. The reductive hydrazine groups of TFH can effectively inhibit the oxidation of Sn2+ and I−, thereby reducing the defect density and energy disorder of Sn─Pb perovskites. Consequently, the TFH‐treated devices achieved a champion PCE of 22.88%, maintaining over 93% of the initial efficiency after continuous one‐sun illumination for 500 h. Combined with a 1.79 eV wide‐bandgap subcell, it has demonstrated a PCE of 28.17% in all‐perovskite TSCs.

Impact of submicron Nb3Sn stoichiometric surface defects on high-field superconducting radiofrequency cavity performance

Nb3Sn film coatings have the potential to drastically improve the accelerating performance of Nb superconducting radiofrequency (SRF) cavities in next-generation linear particle accelerators. Unfortunately, persistent Nb3Sn stoichiometric material defects formed during fabrication limit the cryogenic operating temperature and accelerating gradient by nucleating magnetic vortices that lead to premature cavity quenching. The SRF community currently lacks a predictive model that can explain the impact of chemical and morphological properties of Nb3Sn defects on vortex nucleation and maximum accelerating gradients. Both experimental and theoretical studies of the material and superconducting properties of the first 100 nm of Nb3Sn surfaces are complicated by significant variations in the volume distribution and topography of stoichiometric defects. This work contains a coordinated experimental study with supporting simulations to identify how the observed chemical composition and morphology of certain Sn-rich and Sn-deficient surface defects can impact the SRF performance. Nb3Sn films were prepared with varying degrees of stoichiometric defects, and the film surface morphologies were characterized. Both Sn-rich and Sn-deficient regions were identified in these samples. For Sn-rich defects, we focus on elemental Sn islands that are partially embedded into the Nb3Sn film. Using finite element simulations of the time-dependent Ginzburg-Landau equations, we estimate vortex nucleation field thresholds at Sn islands of varying size, geometry, and embedment. We find that these islands can lead to significant SRF performance degradation that could not have been predicted from the ensemble stoichiometry alone. For Sn-deficient Nb3Sn surfaces, we experimentally identify a periodic nanoscale surface corrugation that likely forms because of extensive Sn loss from the surface. Simulation results show that the surface corrugations contribute to the already substantial drop in the vortex nucleation field of Sn-deficient Nb3Sn surfaces. This work provides a systematic approach for future studies to further detail the relationship between experimental Nb3Sn growth conditions, stoichiometric defects, geometry, and vortex nucleation. These findings have technical implications that will help guide improvements to Nb3Sn fabrication procedures. Our outlined experiment-informed theoretical methods can assist future studies in making additional key insights about Nb3Sn stoichiometric defects that will help build the next generation of SRF cavities and support related superconducting materials development efforts. Published by the American Physical Society 2024

The Effect of Kappa Carrageenan Composition on the Characteristics of Chitosan-Kappa Carrageenan Hydrogel Film

Chitosan-Kappa Carrageenan (Chit-KC) hydrogel films have been made using a casting method with different compositions. This research aimed to investigate the effects of different compositions on the chemical, physical, and mechanical characteristics of the Chit-KC hydrogel films. The compositions of the kappa carrageenan in the Chit-KC films were 0%, 16.67%, 33.33%, 50.0%, and 100.0%. The films were characterized using FTIR, SEM, DTA-TGA, and XRD instruments to analyze their functional groups, morphology, thermal properties, and crystallinity. They were also tested for their solubility, swelling, water vapor permeability (WVP), and mechanical characteristics. The results revealed that the addition of kappa-carrageenan induced the formation of a polyelectrolyte complex. The polyelectrolyte complex caused an increase in swelling, crystallinity, and WVP values and a decrease in solubility, tensile strength, elongation, and elasticity. It also caused the formation of film layers and granules on the surface of the hydrogel film. The IR spectra exhibited that the Chit-KC hydrogel films contained O-H, C-H, C=O, S=O, C-O, and C-O-C groups. The DTA-TGA test results revealed that the film began decomposing at around 200°C and re-decomposing at 300°C.

EXTH-71. A MECHANISTIC INVESTIGATION INTO AUGER THERAPY: 2-DIMENSIONAL THIN-FILMS TO CHARACTERIZE THERAPEUTIC RANGEIN VITRO

Abstract Metallic nanoparticles can improve the accuracy and effectiveness of conventional radiotherapy in the treatment of solid tumors through a light-matter interaction known as the Auger effect. In this work, we present the assembly of an iron oxide (Fe3O4) nanoparticle (NPs) layer within a biocompatible polyelectrolyte film using ionic self-assembly to enable the spatial separation of NPs from their target cells. Films exhibited uniform nanoparticle coverage as well as strong stability in cell culture conditions. To investigate the applicability of NMDR with non-internalized NPs, conditions with (NP-PEM) and without (PEM) embedded nanoparticles were used to evaluate the therapeutic effect of physically separated nanoparticles on cells cultured on the film surface via a measure of intracellular reactive oxygen (ROS) generation and histone phosphorylation (yH2AX) after irradiation from a 137Cesium source. Cells cultured on NP-PEM demonstrated a 78.4% increase in ROS generation when compared to cells cultured on PEM films. When adjusting for cell count, NP-PEM films induce 70.5% greater ROS generation. In investigating nanoparticle-mediated deposition of radiation (NMDR), these films allow for the determination of the extent of the therapeutic effect when NPs are not internalized into their targeted cells, potentially providing indications with respect to off-target effects. Cells were irradiated on films with nanoparticle distances from 25.9 nm to 97.5 nm to interrogate the NMDR effect size at a range of distances. yH2AX phosphorylation exhibited an exponential decay until 69.8 nm, where there was no difference when compared to nanoparticle-free films. This work highlights the ability of iron oxide NPs to deliver NMDR at a known, quantifiable distance, providing insights for further translational applications.

Depth Profiles of Crystallinity and Preferential Orientation and Surface Characteristics of Sputter‐Deposited CeO2 Thin Film Buffer Layers on Sapphire Substrates Evaluated Through Two‐Dimensional Grazing‐Incidence X‐Ray Diffraction

ABSTRACTTwo‐dimensional grazing‐incidence wide‐angle X‐ray diffraction data were acquired from CeO2 thin films serving as buffer layers on r‐cut sapphire substrates to investigate the depth profiles of crystallinity and preferential orientation as well as surface conditions. The thin film samples were sputter‐deposited under different conditions. Data were obtained at an X‐ray wavelength of 0.100 nm at 0.02° intervals from 0.06° to 0.30° at the grazing‐incidence angle. A 60‐nm‐thick CeO2 thin film sputter‐deposited under Ar (Ar‐60) and a 100‐nm‐thick CeO2 thin film sputter deposited using 10 vol.% O2 in Ar (O+Ar‐100) were found to have partially oriented three‐dimensional bulk crystal structures with preferential orientation in the (100) direction near the surface. The lattice constant for the Ar‐60 film was found to be approximately 0.30% smaller than that for a CeO2 standard, whereas the lattice constant for the O+Ar‐100 film was approximately 0.50% larger. Lattice mismatch between the CeO and CeO2 on the substrate surface is evidently not an issue based on the lattice constants near the surface. Hence, both films could be considered to represent optimal buffer layers for YBa2Cu3O6+δ thin film growth. However, even in the case of a CeO2 thin film suitable for use as a buffer layer, the difference in lattice constants between the interior and surface of an Ar‐60 film was found to be relatively small, whereas that for an O+Ar‐100 film was relatively large. These results show that it is important to analyze the film surface in detail by reducing the incidence angle to less than 0.1°.

Efficiency Improvement on Indium Tin Oxide Films for Dye-Sensitized Solar Cell Using Oxygen Plasma by Bias-Magnetron RF Sputtering Process

Dye-sensitized solar cells (DSSCs) are among the most widely studied thin-film solar cells because of their cost-effectiveness, low toxicity, and simple fabrication method. However, there is still much scope for replacing current DSSC materials due to their high cost, low volume, and lack of long-term stability. Accordingly, indium tin oxide (ITO)-nanorod films were fabricated by electron (E)-beam evaporation using the glancing angle deposition method in this study. Then, the ITO-nanorod was treated with oxygen plasma via a bias-magnetron radio-frequency (RF) sputtering process to improve the efficiency of DSSCs under a varying gas flow rate of 20, 40, 60, 80, and 100 sccm. The field emission scanning electron microscopy (FE-SEM) investigation of the ITO film structure revealed that the obtained nanorod structures have slightly different diameters. At the same time, an increase in the oxygen flow rate resulted in a rougher film surface structure. In this, the lower sheet resistance was received because of rougher morphology. When comparing the DSSCs efficiency (η) test results, we found that at a gas flow rate of 100 sccm, the highest efficiency value showed 9.5%. On the other hand, the ITO-nanorod without plasma treatment exhibited the lowest η. Hence, plasma technology can be practically applied to improve the η of DSSC devices. This study will be a prototype of a highly advanced solar cell manufacturing method for the solar cell industry.

Rapid quantitative analysis of semi-volatile organic compounds in indoor surface film using direct analysis in real time mass spectrometry: a case study on phthalates

Abstract. Direct analysis in real time mass spectrometry (DART-MS) has recently emerged as a promising approach for measuring semi-volatile organic compounds (SVOCs) on indoor surface films. However, its broader application in indoor environments is limited by low measurement repeatability and no separation of isomers. Herein we developed a sampling suite of indoor surface films for DART-MS analysis, optimized settings of DART to obtain higher analytical performance, and demonstrated the possibility of separating isomeric compounds using tandem mass spectrometry (MS/MS). Two pairs of isomeric phthalate esters, including di(2-ethylhexyl) phthalate (DEHP) and di-n-octyl phthalate (DnOP) and diisobutyl phthalate (DiBP) and di-n-butyl phthalate (DnBP), were used as examples for method optimization and validation. Under optimized conditions, the instrument responses for all four compounds exhibited good linearity (r>0.992) and acceptable repeatability (intraday relative standard deviation (RSD) < 11.0 %). The limits of quantification for the four phthalate esters ranged from 0.042 to 0.24 ng cm−2. The uncertainty in the separation of isomeric components using MS/MS was < 11.4 %, which is acceptable for real sample analysis. To further assess the developed method, we analyzed 10 film samples collected side by side in an occupied office. DnOP was not detected. The RSD among samples was 6.1 % for DEHP, 4.6 % for DnBP, and 10.4 % for DiBP, indicating the overall good repeatability of the collection and measurement method developed. With improved performance, the developed method increases the feasibility of the DART-MS technique for monitoring the dynamics of chemical composition of indoor surface films.

Nanostructure of TiO\(_{2}\) and WO\(_{3}\) multilayer films deposited on ITO glass for electrochromic enhanced photocatalytic activity

The photocatalytic activity (PA) by electrochromic (EC) enhancement of single and multilayer films of TiO2, WO3, TiO2/WO3, and WO3/TiO2 was investigated. All films were deposited from metal on an ITO glass substrate using direct current (DC) magnetron sputtering via an oblique angle deposition (OAD) technique at 85°. Subsequently, a thermal oxidation (TO) process at 500℃ was applied for the samples to form metal oxide films. The morphology, elemental composition, crystal structure, and optical properties were studied by using field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffractometry (XRD), and UV-vis spectroscopy, respectively. The photocatalytic properties were investigated by showing the degradation rate of methylene blue (MB) solution as an organic pollutant that was examined under ultraviolet irradiation of 300 µW∙cm‒2. The film samples were investigated by comparing the pre-color and colored states that were achieved through the EC process. The EC properties of WO3 led to increased charge insertion on the film surface. This observation was further supported by cyclic voltammetry (CV) testing, which revealed a higher current density for the thin film samples. The photodegradation results showed that the samples in the colored state exhibited a significantly higher degradation rate of MB compared to the pre-color state.

Pyridalthiadiazole-Based Molecular Chromophores for Defect Passivation Enables High-Performance Perovskite Solar Cells.

Passivation of defects at the surface and grain boundaries of perovskite films has become one of the most important strategies to suppress nonradiative recombination and improve optoelectronic performance of perovskite solar cells (PSCs). In this work, two conjugated molecules, abbreviated as CPT and SiPT, are designed and synthesized as the passivator to enhance both efficiency and stability of PSCs. The CPT and SiPT contain pyridalthiadiazole (PT) units, which can coordinate with undercoordinated Pb2+ at the surface and grain boundaries to passivate the defects in perovskite films. In addition, with the incorporation of CPT, the crystallized perovskite films exhibit more uniform grain size and smoother surface morphology relative to the control ones. The efficient passivation by CPT also results in better charge extraction and less carrier recombination in PSCs. Consequently, the CPT-passivated PSCs yield the highest power conversion efficiency (PCE) of 23.14 % together with better storage stability under ambient conditions, which is enhanced relative to the control devices with a PCE of 22.14 %. Meanwhile, the SiPT-passivated PSCs also show a slightly enhanced performance with a PCE of 22.43 %. Our findings provide a new idea for the future design of functional passivating molecules towards high-performance PSCs.

Hafnium dioxide obtained by atomic layer deposition possesses the ability to induce the formation of biological apatite

The research explored the spontaneous formation of the BAp precursor on surfaces of HfO2 films obtained by Atomic Layer Deposition (ALD). It has been found that a careful selection of ALD growth conditions, followed by rapid thermal annealing (RTP) is crucial to achieve bioactivity of the films. Simulated Body Fluid experiment was used as a reliable test of the film's functionality as bone implant coating. SEM, XRD and XPS investigations proved that amorphous calcium orthophosphate structures were formed on the HfO2 films. These structures are of importance for biomineralization of bones. Physical and chemical characterization of the films was an integral part of the research. Such approach allowed us to achieve biomaterial functionality while maintaining the films’ quality. The finding has significance for future progress in personalized traumatological medicine.

Boric acid-free electrodeposition process and solar–thermal energy conversion of and Ni-carbon black nanocomposite coatings

AbstractThis work focuses on the development of a multi-layered system, of bright nickel electrodeposited on a steel substrate, and a second layer composed of black nickel either with or without carbon black nanoparticles (CB NPs), aiming for an efficient conversion of incident solar radiation into heat, for the fabrication of solar collectors. The structural characterization, revealed that the bright nickel film was composed of metallic nickel, while the black coatings contained amorphous nickel compounds. SEM analysis unveiled the presence of pinholes on the surface of the bright nickel film, suggesting that the black nickel coating was ineffective in sealing them. The appearance of cracks with the increase in the deposition time was observed. With the nanocomposite of black nickel and CB NPs, these cracks can be avoided and the pinholes sealed. The CB NPs were found to reduce reflectance, enhancing the conversion of solar energy into heat. Graphical abstract

Layer-by-Layer Deposition of Hollow TiO2 Spheres with Enhanced Photoelectric Conversion Efficiency for Dye-Sensitized Solar Cell Applications

Fabricating photoanodes with a strong light-scattering effect can improve the photoconversion efficiency of dye-sensitized solar cells (DSSCs). In this work, a facile microwave hydrothermal process was developed to prepare Au@TiO2 core–shell nanostructures, and then the Au core was removed by etching, resulting in hollow TiO2. Morphological characterizations such as field emission scanning and transmission electron microscopy measurements have been used for the successful formation of core–shell and hollow TiO2 nanostructures. Next, we attempted to deposit the different-sized hollow TiO2-based microspheres simultaneously on the surface of small-sized TiO2 nanoparticles-based compact film as light-scattering layers via electrophoretic deposition. The deposited hollow TiO2 microspheres constitute bi- and tri-layers that not only improve the light-harvesting properties but also speed up the photogenerated charge transfer. Compared to commercial TiO2 compact film (4.75%), the resulting bi-layer and tri-layered films-based DSSCs displayed power conversion efficiencies of 6.33% and 8.08%, respectively. It is revealed that the deposited bi- and tri-layered films can enhance the light absorption ability via multiple photon reflection. This work validates a novel and controllable strategy to develop light-scattering layers with increased light-harvesting properties for highly efficient dye-sensitized solar cells.

Impact of NiO nanoparticle decoration on the surface of SnO2 thin films for gas sensing

Impact of NiO nanoparticle decoration on the surface of SnO2 thin films for gas sensing

Impact of Temperature and Substrate Type on the Optical and Structural Properties of AlN Epilayers: A Cross-Sectional Analysis Using Advanced Characterization Techniques

AlN, with its ultra-wide bandgap, is highly attractive for modern applications in deep ultraviolet light-emitting diodes and electronic devices. In this study, the surface and cross-sectional properties of AlN films grown on flat and nano-patterned sapphire substrates are characterized by a variety of techniques, including photoluminescence spectroscopy, high-resolution X-ray diffraction, X-ray photoelectron spectroscopy, ultraviolet photoelectron spectroscopy, and Raman spectroscopy. The results indicate that different sapphire substrates have minimal impact on the photoluminescence spectrum of the epitaxial films. As the temperature increased, the radius of curvature of the AlN films increased, while the warpage decreased. The AlN films grown on nano-patterned substrates exhibited superior quality with less surface oxidation. During the growth of AlN thin films on different types of substrates, slight shifts in the energy bands occurred due to differences in the introduction of carbon-related impurities and intrinsic defects. The Raman shift and full width at half maximum (FWHM) of the E2(low), A1(TO), E2(high), E1(TO), and E1(LO) phonon modes for the cross-sectional AlN films varied with the depth and temperature. The stress state within the film was precisely determined with specific depths and temperatures. The FWHM of the E2(high) phonon mode suggests that the films grown on nano-patterned substrates exhibited better crystalline quality.

Phase-selective fabrication of Cu-based films by magnetic field-assisted sparking process for improved photocatalytic dye degradation and CO2 reduction

Copper-based films (Cu2(OH)3NO3, Cu2O, and CuO) were successfully synthesized using a sparking process under an external magnetic field, without requiring an annealing process. We thoroughly investigate the impact of magnetic field orientation on the structural, morphological, and optical properties of the films, along with their performance in photocatalytic degradation of methylene blue (MB) and carbon dioxide (CO2) reduction. Field-emission scanning electron microscopy (FE-SEM) images reveal that the CuEB(S) sample displays secondary particles forming spherical, dense clusters, whereas the CuEB(N) sample exhibits larger, loosely packed clusters. In contrast, the cluster-like structures disperse in the CuEB(P) sample, resulting in a smoother film surface aligned with the parallel magnetic flux direction. Upon close observation, rice-shaped particles of varying sizes (26.3–60.3 nm) were found stacked together. This study presents a facile method to selectively fabricate films comprising single-phase Cu2(OH)3NO3, a CuO/Cu2O composite, or a combination of all phases by manipulating the external magnetic field orientation during the sparking process. All synthesized materials exhibit photocatalytic activity, with the heterojunction composed of CuO, Cu2O, and Cu2(OH)3NO3 demonstrating superior performance. This heterostructure achieved up to a 180 % enhancement in MB degradation and approximately doubled the CO2-to-CO conversion rate to 16.09 μmol g–¹ h–¹ compared to the sample prepared without a magnetic field.

Unique and efficient modulation of polycarbazole thin film surface morphology by electrochemical, photochemical and self-assembly techniques

Surface morphology significantly impacts the performance of conducting polymers by influencing charge transport, electromechanical properties, and diffusion dynamics. Understanding and controlling surface morphology is crucial for optimizing the performance of conducting polymers in various applications. In this work, we synthesized for the first time the Azo-SH molecule containing azobenzene, thiol and carbazole groups, thus enabling it photoactivity, electroactivity and self-assembly properties. By integrating the photosensitive azobenzene and the thiol-terminated functional molecule into the electroactive carbazole group, it has been obtained unique surface morphologies that modulating effectively and efficiently via electrochemical, photochemical and self-assembly. The electroactive and photoactive polymer films obtained by electropolymerization were characterized by AFM, e-QCM, electrochemical impedance and XPS techniques. This study has demonstrated as a proof of concept that the surface properties of thin films formed with all-in-one type molecules can be modified by electrochemical, photochemical and self-assembly techniques. Surface morphology modulation of thin films by including wettability, polarity, dipole moment and other properties would provide a powerful approach to prepare functional organic devices.