Vertical Deposition Research Articles

Atmospheric deposition and trajectories of antimony in Central Europe

Antimony (Sb) concentrations were measured in wet atmospheric deposition at 10 high-elevation sites in the Czech Republic (Central Europe) during three winter seasons (2009–2011). Soluble and insoluble Sb forms were quantified in snow (vertical deposition) and rime (horizontal deposition) on mountain summits located equidistantly near the Czech borders with Austria, Germany and Poland. The highest Sb concentrations were found in the soluble form in rime (0.47 μg L−1), while the lowest Sb concentrations were those in the insoluble form in snow (0.017 μg L−1). The estimated average Sb deposition rate in Central Europe amounted to 1.3. 10−4 g m−2 yr−1. Most Sb was deposited in the soluble form in snow (7.9. 10−5 g m−2 yr−1), followed by the soluble form in rime (3.5. 10−5 g m−2 yr−1). The corresponding insoluble fraction contained less Sb, namely 1.2. 10−5 g m−2 yr−1 in snow and 2.3. 10−6 g m−2 yr−1 in rime. The average Sb deposition in Central Europe, measured at an altitude of 1000 m a.s.l., was by six orders of magnitude higher compared to Sb deposition in the Arctic (7. 10−10 g m−2 yr−1), and by four orders of magnitude lower compared to Sb deposition in a Sb–Hg mining district in China (7 g m−2 yr−1). Using the HYSPLIT model, backward trajectories of air masses indicated that the Sb sources were predominantly situated in Upper and Lower Silesia.

On different 3D printing methods and fracture performance in DCB composite specimens including structured interfaces

This work experimentally analyzes the influence of the printing direction on the fracture resistance capabilities of composite specimens incorporating structured interfaces in their geometrical definition. In particular, we compare horizontal and vertical direction fiber deposition using 3D printing capabilities in order to identify the best scenarios that maximize the corresponding fracture performances. For this purpose, DCB specimens including improved structured interfaces designed with fiber in the profile region of the specimen are produced. These designs were created using 3D printing in long fiber composites. Experimental evidences reveal a remarkable increase in fracture toughness in structured interface profiles printed in the vertical direction compared to structured interface profiles printed in the horizontal direction, specifically 217% for the best configuration and 118% for the most unfavorable configuration. Present results show the potential benefits for the generation of novel design concepts with improvements in fracture resistance capabilities, fostering new perspectives in the definition of composite structures.

Wire-arc additive manufacturing of structures with overhang: Experimental results depositing material onto fixed substrate

As additive manufacturing (AM) technology grows both more advanced and more available, the challenges and limitations are also made more evident. Most existing solutions for AM build structures layer by layer using strictly vertical material deposition. As each layer must vertically adhere to the previous layer, support structures must be added if there are to be any kinds of overhangs. For methods requiring the build to be performed within a chamber, the size of the structure is also very limited. The research presented in this paper explores possible solutions to these challenges, focusing on wire-arc additive manufacturing in order to effectively build structures that can not easily be constructed using in-box, layer-based methods for AM. By non-vertical material deposition using an industrial robot manipulator, metal structures with overhangs are built onto a fixed, horizontal surface without any support structures. Cross sections of two different structures are examined by optical microscopy and hardness measurements to reveal potential differences between the areas with and without intersections or overhang.

The construction of photonic crystal/Cu2+ doped TiO2-SiO2 multilayer structured film for enhanced visible light photocatalytic performance: The synergistic effect between the different layers

For photocatalytic films, the low degradation efficiency has become an urgent problem to be solved due to the less amount of photocatalytic component. Therefore, it is particularly important to control the matching of interaction effect between each layer by adjusting the photonic crystal and doping, so as to achieve the best photocatalytic performance. Herein, Cu 2+ doped TiO 2 -SiO 2 (CTS) layer was deposited on SiO 2 photonic crystal layer to construct multilayer structured films via vertical deposition method and calcination process. The photonic crystal/Cu 2+ doped TiO 2 -SiO 2 (PC/CTS) film shows the best photocatalytic performance although the amount of catalytic material is little, that is, the degradation rate of RhB by PC/CTS can reach 48.21% after 180 min of visible light irradiation, which is nearly 5 times than that of single-layer CTS film (10.97% after 180 min). Furthermore, a layer of amorphous SiO 2 was deposited between SiO 2 photonic crystal film and photocatalyst CTS layer to investigate the optical local interaction range of SiO 2 photonic crystal. Finally, the mechanism of multilayer structured PC/CTS composite film is discussed, indicating that the synergistic effect between different layers is a decisive factor for effectively improving the visible photocatalytic performance of thin films. • Photonic crystal/Cu 2+ doped SiO 2 -TiO 2 film was constructed by vertical deposition method. • The influencing factors that can match different layers were studied. • The mechanism was explained by the synergistic effect between different layers.

(Digital Presentation) Synthesis of Multisize Layered Silica Inverse Opal Photonic Crystals

Today, human beings have found an increasing need for energy. The ever-increasing effort to shrink information systems at higher speeds has led to the common idea that photons are used as carriers of information instead of electrons. Photonic crystals have a structure whose dielectric constants and refractive indices change alternately in one, two, or three dimensions, which are called one-dimensional, two-dimensional, and three-dimensional photon crystals. Periodicity in the refractive index of the crystal structure causes a photonic bandgap that includes a range of frequencies in which light with a frequency of this range is not allowed to pass the crystal structure and is reflected or absorbed.In this work, Poly(methyl methacrylate) (PMMA) microspheres of different sizes were first synthesized using the suspension polymerization method. Concentrations of used materials including initializer, monomer, reaction temperature, reaction time, and rotation speed play important roles in determining the final diameter of PMMA microspheres. Then, the vertical deposition method is used for the growth of multi-layered opals of different sizes, one on top of another. On the other hand, inverse opals have porous and organized structures that are made using opals as the template. The method used in this study to make multisize layered inverse opal made of silica is as follows: 1- Fabrication of a uniform layer of polymer microspheres on a glass substrate with a specified size as a colloidal crystal template 2- Infiltration of void space between the microspheres of the opal template 3- Creating the next layer with different size on the first layer 4- Reinjection of the silica precursor. 5- Repeating the coating layer and injection of the precursor. 6- Finally, selective removal of the opal template by calcination or etching with an organic solvent to create the porous structure of the multisize layered Silica inverse opal photonic crystals. The silica precursor contains a mixture of ethanol, TEOS tetraethyl orthosilicate, and hydrochloric acid.The results show that the fabricated inverse opals are organized, crack-free, and uniform. It is possible to make the desired number of layers by changing the concentration of the PMMA microspheres' colloidal suspension. By changing the characteristics of photonic crystals, such as their constituent materials and refractive indices, lattice constants, and the number of layers, it is possible to control their photonic properties which are beneficial for different applications.

Simple and practical methods for utilizing parylene C film based on vertical deposition and laser patterning

We propose two novel methods to effectively utilize parylene C films. First, we demonstrate a vertical deposition method capable of depositing a parylene C film of the same thickness on both sides of a sample. Through this method, we have formed parylene C films with a thickness of 4 μm on both sides of the sample with a thickness deviation of less than 2.5%. Further optical verification indicates that parylene C films formed by this method have a very uniform thickness distribution on each side of the surfaces. Second, we propose a debris-tolerant laser patterning method as a mask-less means to fabricate self-supporting ultrathin parylene C films. This method does not involve any photolithography and entails a simple and rapid process that can be performed using only a few materials with excellent biocompatibility. It is demonstrated that patterned parylene C films exhibit a high degree of surface uniformity and have various geometrical shapes so that they can be used for substrates of highly flexible and/or stretchable devices. Finally, we use both of the proposed methods to fabricate flexible, stretchable, and waterproof-packaged bifacial blue LED modules to illustrate their potential in emerging applications that would benefit from such versatile form factors.

Investigation of build strategies for microfeatures fabrication using laser powder bed fusion

Modifying the surface topography by fabricating the microfeatures on-top of interacting surfaces has the potential to enhance the tribological behavior of mechanical components having sliding motion. In the additive manufacturing process, Laser powder bed fusion process (LPBF) is chosen to fabricate microfeatures for metals. In LPBF, microfeature characteristics are based on the energy supplied and strategies used for fabrication. In this work, a single layer single track (SLST) experiment is carried out for a different combination of the laser power and scanning speed for fabricating continuous and uniform track width with good shape controllability. Further, the interaction between the lateral and vertical deposition to a single track is also analyzed by using single layer double track (SLDT) and double layer single track (DLST) strategies. It has been found that the LPBF process parameters have a significant influence on the track's morphology and its geometry irrespective of the build strategies. The continuous and uniform tracks are formed when the LED is greater than 0.3 J/mm for investigated build strategies. The microfeatures of width 150 μm to 300 μm and height 40 μm is recommended to fabricate by SLST strategy whereas for 60 μm height of microfeature DLST strategy is recommended. If the microfeatures width is greater than 300 μm then SLDT strategy is recommended. SLST and DLST show good control on the microfeatures characteristics as compared to SLDT strategy.

Improvement of nanopore structure SnO2 electron-transport layer for carbon-based CsPbIBr2 perovskite solar cells

SnO2 has been widely used in perovskite solar cells (PSCs) and LEDs as a flat electron transport layer (ETL), because of its low preparation temperature and low energy consumption. However, electrons are easily captured by defects on the ETL, resulting in ion migration of perovskite, which increases the extensive hysteresis index (HI) of PSCs. By preparing surface microstructures (such as mesoporous structure and nanowire array) on the ETL, the electron transmission capacity can be improved effectively, which reduces the HI and increases photoelectric conversion efficiency (PCE).In this paper, we use a simple and high fault-tolerant method to prepare the SnO2 ETL with nanopore structure (NP–SnO2) at low temperature. The polystyrene microsphere sphere templates were prepared on flat SnO2 film by a vertical deposition method, and then SnO2 films with NP-SnO2 were prepared by template method. The size and density of nanopores in the NP-SnO2 are controlled by controlling the size of PS spheres and the concentration of PS colloidal solution. The nanopores structure could improve the quality of CsPbIBr2 crystal films. Moreover, the nanopore structure can increase the contact area between the SnO2 ETL and the CsPbIBr2 film, which provides more channels for electron transmission.The results show that CsPbIBr2 PSCs based on NP-SnO2 ETL can obtain the champion PCE, which is 6.68% (25.33% higher than the PSCs based on flat SnO2 ETL), and the HI of the PSCs based on NP-SnO2 ETL was reduced from 0.36 to 0.17.

Model evaluation of short-lived climate forcers for the Arctic Monitoring and Assessment Programme: a multi-species, multi-model study

Abstract. While carbon dioxide is the main cause for global warming, modeling short-lived climate forcers (SLCFs) such as methane, ozone, and particles in the Arctic allows us to simulate near-term climate and health impacts for a sensitive, pristine region that is warming at 3 times the global rate. Atmospheric modeling is critical for understanding the long-range transport of pollutants to the Arctic, as well as the abundance and distribution of SLCFs throughout the Arctic atmosphere. Modeling is also used as a tool to determine SLCF impacts on climate and health in the present and in future emissions scenarios. In this study, we evaluate 18 state-of-the-art atmospheric and Earth system models by assessing their representation of Arctic and Northern Hemisphere atmospheric SLCF distributions, considering a wide range of different chemical species (methane, tropospheric ozone and its precursors, black carbon, sulfate, organic aerosol, and particulate matter) and multiple observational datasets. Model simulations over 4 years (2008–2009 and 2014–2015) conducted for the 2022 Arctic Monitoring and Assessment Programme (AMAP) SLCF assessment report are thoroughly evaluated against satellite, ground, ship, and aircraft-based observations. The annual means, seasonal cycles, and 3-D distributions of SLCFs were evaluated using several metrics, such as absolute and percent model biases and correlation coefficients. The results show a large range in model performance, with no one particular model or model type performing well for all regions and all SLCF species. The multi-model mean (mmm) was able to represent the general features of SLCFs in the Arctic and had the best overall performance. For the SLCFs with the greatest radiative impact (CH4, O3, BC, and SO42-), the mmm was within ±25 % of the measurements across the Northern Hemisphere. Therefore, we recommend a multi-model ensemble be used for simulating climate and health impacts of SLCFs. Of the SLCFs in our study, model biases were smallest for CH4 and greatest for OA. For most SLCFs, model biases skewed from positive to negative with increasing latitude. Our analysis suggests that vertical mixing, long-range transport, deposition, and wildfires remain highly uncertain processes. These processes need better representation within atmospheric models to improve their simulation of SLCFs in the Arctic environment. As model development proceeds in these areas, we highly recommend that the vertical and 3-D distribution of SLCFs be evaluated, as that information is critical to improving the uncertain processes in models.

Combining ZnO inverse opal and ZnO nanorods using ALD and hydrothermal growth

In this paper, we combine the atomic layer deposition synthesis method of inverse opal with the hydrothermal growth of nanorods. From 460 nm polystyrene nanospheres opal crystals were produced using vertical deposition on Si wafers. The opal templates were covered with ZnO by atomic layer deposition. High temperature annealing was used to remove the polystyrene nanospheres to obtain the inverse opal structure. For the hydrothermal growth of ZnO nanorods, two production routes were analysed: hydrothermal reaction before and after the removal of the template. The two paths produced two distinct structures, one with plate like formations and one with nanorods, respectively. Also, the sample modified by the hydrothermal growth after the annealing showed slight differences in optical properties compared to the regular inverse opal. Morphology, composition and structure of the samples were explored using SEM, EDX and XRD. Optical properties were investigated with reflectance UV–Vis spectroscopy. Thermal stability of the polystyrene opal was determined using TG.

Photonic crystal films with upconversion luminescence based on the self-assembly of polystyrene encapsulated NaYF4:Ln3+ composite microspheres for dual-mode optical code

The design and fabrication of advanced materials with multiple optical states for constructing security code are of great value in anti-counterfeiting. Herein, novel upconversion photonic crystal (UCPC) films with tunable luminescence and structural color were prepared by vertical deposition of polystyrene encapsulated NaYF4:Ln3+ (CSNPs@SiO2/PS) composite microspheres. The composite microspheres were synthesized by sequential coating technology. Firstly, NaYF4:Ln3+@NaYF4 core/shell nanoparticles (CSNPs) were synthesized and served as upconversion luminescent emission centers. Then, the CSNPs were further coated by a SiO2 shell with pendant double bond to form CSNPs@SiO2-MPS. Afterward, mono-dispersed CSNPs@SiO2/PS composite microspheres were synthesized by emulsion polymerization of styrene in the presence of CSNPs@SiO2-MPS. By tailoring the doped lanthanide ions in CSNPs and adjusting the diameter of the composite microspheres, UCPC films with diverse upconversion fluorescence and structural color can be obtained. As a proof of concept, these different kinds of UCPC films were employed as information coding units to construct dual-mode anti-counterfeiting code. Our protocol provided a new security strategy for information storage.

Fluvial sediment source to sink transfer at the Yellow River Delta: Quantifications, causes, and environmental impacts

Intensified human interventions in river basins and deltas lead to more complexities of environmental changes during the Anthropocene. Changes in river regime especially a dramatic reduction in sediment delivery increase challenges of the morphological and ecological sustainability of river deltas. In evaluating deltaic risks and sustainable solutions, researches are often limited to single geomorphic units of the deltaic system, and investigations of sediment source to sink transfer at river deltas under recent river regimes are often missing. The Yellow River Delta (YRD) presents as a typical megadelta under stressors induced by changing environments. This study utilizes a period of 20-yr high-resolution topography data of the deltaic channel and its subaqueous delta to investigate sediment transport and source to sink process by integrated methods of field measurements and numerical simulations. The results indicate that the deltaic channel has transitioned from net accretion to erosion after the implementation of the Water-Sediment Regulation Scheme (WSRS) in 2002. The active river mouth experienced a slow accretion phase since the river channel diverted to Qing 8 channel, with a reduced vertical deposition rate of 0.15 m/yr, whilst its adjacent Gudong littoral zone had a −0.11 m/yr erosion rate. Under the new fluvial regime, the river-borne suspended sediment tends to transport southwards to the Laizhou Bay, followed by the river-derived sediment transport eastward and northward to the offshore delta. It is clear that with the continued human activities in the region, the YRD is at the potential state of deltaic transition both in the deltaic channel and its subaqueous delta. This transition is believed to be beneficial to the deltaic channel stability, but it could significantly impact on the geomorphic and ecologic sustainability of the entire deltaic system.

Enhanced thickness uniformity of large-scale α-Ga2O3 epilayers grown by vertical hot-wall mist chemical vapor deposition

Smooth surface morphology and high thickness uniformity heteroepitaxy of corundum-structured ( α- ) gallium oxide (Ga 2 O 3 ) crystalline thin films on 100-mm diameter c -plane sapphire substrates were successfully demonstrated using vertical hot-wall mist chemical vapor deposition (CVD). The growth rate and surface morphology of the epitaxial layers were numerically and experimentally found to be dependent on the diameter of the precursor-diluted microdroplets approaching the substrate surface. Since the microdroplet is gradually evaporated while traveling through the furnace, the growth variables such as temperature, mist-flow velocity, and substrate position were tuned to obtain a suitable diameter of microdroplets approaching the substrate. In this study, the diameter of the approaching microdroplet was ≈2 μm, which was optimal for the smooth surface (root mean square roughness ≈1 nm) of α -Ga 2 O 3 epitaxial layers with a growth rate of ≈230 nm/h. Due to the even flow of mist in the vertical furnace, high thickness uniformity of the α -Ga 2 O 3 epitaxial layer is guaranteed on large-scale substrates, with a standard deviation of thickness as small as 28 nm, paving the way for highly reliable Ga 2 O 3 -based electric and optoelectronic devices.

Fabrication of sub-50 nm nanochannel array by an angle forming lift-off method

Nanoimprint is a low-cost and high-precision nano-pattern replication technology. In the nanoimprint manufacturing process, the quality of nano-mold directly determines the quality of nano-pattern. In this paper, we proposed a method for manufacturing silicon nano-mold using inverted trapezoidal photoresist (AZ5214E). During the manufacturing process, a nanogap was formed due to the size difference between the top and bottom surfaces of inverted trapezoidal photoresist when the Cu vertical deposition process was completed. Then the nanogap pattern was transferred to the silicon substrate by deep reactive ion etching (DRIE) to create nanochannels, and sub-50 nm silicon nano-molds were obtained. The influence of UV exposure parameters on photoresist sidewall angle was studied. The effect of photoresist sidewall angle on the width of nanogaps was analyzed, which ultimately affects the size of nanochannel. We believe that the proposed method can play a certain role in promoting the development of nanotechnology and nanoscience.

Preparation of 2D Periodic Nanopatterned Arrays through Vertical Vibration-Assisted Convective Deposition for Application in Metal-Enhanced Fluorescence

The performance of a metal-enhanced fluorescence (MEF) substrate is fundamentally based on the orientation of the metal nanostructures on a solid substrate. In particular, two-dimensional (2D) periodic metallic nanostructures exhibit a strong confinement of the electric field between adjacent nanopatterns due to localized surface plasmon resonance (LSPR), leading to stronger fluorescence intensity enhancement. The use of vertical vibration-assisted convective deposition, a novel, simple, and highly cost-effective technique for preparing the 2D periodic nanostructure of colloidal particles with high uniformity, was therefore proposed in this work. The influences of vertical vibration amplitude and frequency on the structure of thin colloidal film, especially its uniformity, monolayer, and hexagonal close-packed (HCP) arrangement, were also investigated. It was found that the vibration amplitude affected film uniformity, whereas the vibration frequency promoted the colloidal particles to align themselves into defect-free HCP nanostructures. Furthermore, the results showed that the self-assembled 2D periodic arrays of monodisperse colloidal particles were employed as an excellent template for a Au thin-film coating in order to fabricate an efficient MEF substrate. The developed MEF substrate provided a strong plasmonic fluorescence enhancement, with a detection limit for rhodamine 6G as low as 10−9 M. This novel approach could be advantageous in further applications in the area of plasmonic sensing platforms.

Size-segregated aerosol fluxes, deposition velocities, and chemical composition in an Alpine valley

The paper presents eddy covariance measurements of aerosol fluxes performed above an Alpine pasture in the Camonica Valley (Italian Alps) during summer 2019 and winter 2020. Vertical fluxes and deposition velocities (vds) were computed for nine aerosol size classes, with geometric mean diameters (GMDs) ranging from 10 nm to 0.76 μm, employing a fast-response electrical low-pressure impactor (ELPI+, Dekati, FI). At the end of each campaign, the concentration of water-soluble ions was estimated from the ion chromatography chemical speciation performed on the multi-impactor filters. K+ concentrations tripled in winter, evidencing the impact of biomass burning emissions, while nitrate, nitrite, ammonium, and sulphate were ascribed to secondary inorganic aerosol (SIA) formation. During summer, classes characterized by downward net daily fluxes presented a high percentage of SIA (> 70%) deposited on the respective filters. Phenomena of growth or coagulation of particles were also detected from the steady increase in concentrations during the day in classes with GMD ≥ 20 nm. Turbulence favoured intense aerosol exchange during the day. During summer nights, low friction velocities (u∗) led to weaker fluxes, while a strong, stable stratification in winter determined aerosol trapping at ground level and non-negligible, mostly negative, fluxes during nighttime. The trends of vds versus aerosol GMDs showed prevailing deposition phenomena under stable atmospheric conditions, with relative humidity higher than or equal to 90%, friction velocity lower than 0.15 m s−1, or wind speed lower than 2 m s−1. Cluster analysis identified groups of days with or without nucleation events and highlighted a rainout effect in summer during a period characterized by intense precipitation.

Organic matter processing through an estuarine system: Evidence from stable isotopes (δ13C and δ15N) and molecular (lignin phenols) signatures

This study unraveled the origin, fate and accumulation of organic matter (OM) of surface sediments, spread between the fresh and marine end members of Guaratuba Bay (SE- Brazil). Sedimentation rates were obtained through the 210Pb sediment dating method, biogenic element accumulation (C-organic carbon, N-nitrogen, P-phosphorus, and lignin phenols) and stable isotopes of organic carbon (δ13C) and nitrogen (δ15N) were measured along the well-defined salinity gradient (0–35). The higher C:N ratios and lower δ13C values signatures indicate major terrestrial contribution in regions dominated by fluvial inputs, while the contributions from autochthonous primary production and mangrove forests were greater in the middle and outer estuarine sectors. A stable isotope mixing model showed that the material contribution from rivers and mangroves in surface sediments ranged from 80 to 90% in the upstream sector, 50–70% in the central sector and 25–50% at the outer region, whereas this contribution decreased to 15–20% in the adjacent ocean. Ratios between phenolic groups indicated material deposited from predominantly woody angiosperms. Vertical CNP deposition, accumulation rates and lignin phenol concentrations along the sedimentary profiles indicated three phases: Phase I, the more recently deposited sediments, which contained the highest CNP sedimentary fluxes; Phase II, dated to be from 1960s to 1990s, was characterized by changes related with increasing deforestation associated to fires; Phase III from the 1920s–1960s, exhibited four-fold lower C, N and P concentrations compared the more recent rates. Along the estuarine gradient, the C accumulation was found to be related to specific sources as indicated by the lignin's, stable isotopes as well as C:N ratios. Furthermore, the vertical accumulation of OM in sediments concomitantly with geochronology showed the recent anthropogenic perturbations in the estuary. This study highlights the land-ocean sedimentary continuum of which are poorly studied with respect to the transport of C, N and P in estuarine systems, reinforcing the presence of a marked land-ocean gradient. Knowledge of isotopic fractions, as well as lignin phenols, for different areas along the estuarine gradient is important as sampling along coastal areas can represent a bias in understanding the transport and cycling of OM to the sea if gradients and specific regions are not taken into account.

Preparation of Quantum Dot-Embedded Photonic Crystal Hydrogel and Its Application as Fluorescence Sensor for the Detection of Nitrite.

The development of fluorescence sensing platforms with excellent photoluminescence capabilities is of great importance for their further application. In this work, a photonic crystal structure was successfully applied to enhance the luminescence performance of fluorescent hydrogel, and the application of the obtained hydrogel as a fluorescence sensor was explored. A polystyrene photonic crystal template was constructed via vertical deposition self-assembly; then, the precursor solution containing polyethylenimine-capped CdS quantum dots (PEI-CdS QDs) and monomers filled in the gap of the template. After the polymerization process, the desired hydrogel was obtained. PEI-CdS QDs endowed the hydrogel with its fluorescence property, while interestingly, the photonic crystal structure showed a significant enhancement effect on the fluorescence-emission capability. The mechanism of this phenomenon was revealed. Moreover, this hydrogel could be used as a reusable fluorescence sensor for the detection of nitrite in water with good selectivity. The limit of detection was determined to be 0.25 μmol/L, which is much lower than the maximum limit for nitrite in drinking water.

Bright Structural Color and High Hydrophobic Properties of Photonic Crystal Films on the Ceramic Glaze Layer via Vertical Deposition Self‐Assembly Method

AbstractIn this work, structural color films on ceramic substrate were prepared through vertical deposition self‐assembly. The morphology, optical property and hydrophobicity of the films were characterized by field‐emission scanning electron microscopy (FE‐SEM), optical photos and contact angle meter. The results show that the SiO2 colloidal crystals with ordered arrangement are successfully immersed into the ceramic glaze after sintered, and the structural color films prepared on the ceramic glaze layer show a periodically ordered structure. Compared with the structural color films on alumina substrate, further researches on the structural color films on ceramic substrate were carried out, and the hydrophobic property and stability of the structural color films on ceramic substrate are better, which is attributed to the combination of SiO2 photonic crystal and ceramic glaze. Moreover, the structural color films on the ceramic glaze layer show excellent hydrophobic performance when the sintering temperature was 600 °C.

Effect of Relative Humidity on the Thickness of Assembled Silica Colloidal Crystal Films.

In order for the colloidal crystal films to be better applied, the influence of relative humidity on the preparation of silica colloidal crystal (SCC) films was systematically studied to solve the problem of different thicknesses of SCC films prepared by different batches under the conditions with the same temperature, concentration of suspension and diameter of the particles. SCC films with 190 nm particles were prepared by static vertical deposition method under different humidity regulated by saturated salt solutions, and the thickness of the films was obtained by an interferometric method. The results showed that the increase in humidity would reduce the thickness of the prepared films, which was believed to be caused by the decrease in evaporation rate after the wetting film absorbs water vapor. A new formula for calculating film thickness was proposed and verified from a series of experiments. With the control of humidity, high-quality SCC films with controlled thickness can be repeatedly prepared.