Intermediate SiO2 Layer Research Articles

Electroluminescence from Silicon‐Based Light‐Emitting Devices with Erbium‐Doped Ta2O5 Films

The visible and near‐infrared (NIR) electroluminescence (EL) from the light‐emitting device (LED) based on the erbium (Er)‐doped Ta2O5 (Ta2O5:Er)/SiO2/Si structure is reported in this study. Wherein, an ≈10 nm thick SiO2 intermediate layer serves as an energy plateau for forming hot electrons, which initially transport from Si via trap‐assisted tunneling mechanism under sufficiently forward bias with the negative voltage connecting with Si. The hot electrons impact‐excite the Er3+ ions incorporated into the Ta2O5 host, leading to the Er‐related EL from the aforementioned LED. It is found that the 750 °Cannealed Ta2O5:Er films are desirable to act as the light‐emitting component. Despite that the Er‐related photoluminescence from the Ta2O5:Er film becomes stronger in turn with the Er‐doping content increasing from nominal 0.75, 1.5 to 3 mol%, it is the Ta2O5:Er film with Er‐doping content of nominal 1.5 mol% rather than 3 mol% that enables the LED to exhibit the strongest EL. Based on the EL lifetime measurement and the structural characterizations, it is believed that the enhanced non‐radiative interactions among the Er3+ ions and the substantial amorphousness of Ta2O5 host caused by the nominal 3 mol% Er‐doping are responsible for the weakened EL as mentioned above.

A Novel Flame-Retardant, Smoke-Suppressing, and Superhydrophobic Transparent Bamboo.

Silica glass, known for its brittleness, weight, and non-biodegradable nature, faces challenges in finding suitable alternatives. Transparent wood, made by infusing polymers into wood, shows promise but is hindered by limited availability of wood in China and fire risks associated with its use. This study explores the potential of utilizing bamboo, which has a shorter growth cycle, as a valuable resource for developing flame-retardant, smoke-suppressing, and superhydrophobic transparent bamboo. A 3-layered flame-retardant barrier, composed of a top silane layer, an intermediate layer of SiO2 formed through hydrolysis-condensation of Na2SiO3 on the surface, and an inner layer of Na2SiO3, has been confirmed to be effective in reducing heat release, slowing flame spread, and inhibiting the release of combustible volatiles, toxic smoke, and CO. Compared to natural bamboo and other congeneric transparent products, the transparent bamboo displays remarkable superiority, with the majority of parameters being notably lower by an entire order of magnitude. It achieves a long ignition time of 116 s, low total heat release (0.7 MJ/m2), low total smoke production (0.063 m2), and low peak CO concentration (0.008 kg/kg). Moreover, when used as a substrate for perovskite solar cells, the transparent bamboo displays the potential to act as a light management layer, leading to a marked efficiency enhancement of 15.29%. The excellent features of transparent bamboo make it an enticing choice for future advancements in flame-retardant glasses and optical devices.

A Bioinspired Bilevel Metamaterial for Multispectral Manipulation toward Visible, Multi-Wavelength Detection Lasers and Mid-Infrared Selective Radiation.

Manipulation of the electromagnetic signature in multiple wavebands is necessary and effective in civil and industrial applications. However, the integration of multispectral requirements, particularly for the bands with comparable wavelengths, challenges the design and fabrication of current compatible metamaterials. Here, a bioinspired bilevel metamaterial is proposed for multispectral manipulation involving visible, multi-wavelength detection lasers and mid-infrared (MIR), along with radiative cooling. The metamaterial, consisting of dual-deck Pt disks and a SiO2 intermediate layer, is inspired by the broadband reflection splitting effect found in butterfly scales and achieves ultralow specular reflectance (average of 0.013) over the entire 0.8-1.6µm with large scattering angles. Meanwhile, tunable visible reflection and selective dual absorption peaks in MIR can be simultaneously realized, providing structural color, effective radiative thermal dissipation at 5-8µm and 10.6µm laser absorption. The metamaterial is fabricated by a low-cost colloidal lithography method combined with two patterning processes. Multispectral manipulation performances are experimentally demonstrated and a significant apparent temperature drop (maximum of 15.7°C) compared to the reference is observed under a thermal imager. This work achieves optical response in multiple wavebands and provides a valuable way to effectively design multifunctional metamaterials inspired by nature.

Atomic Level Chemical and Structural Properties of Silicon Surface and Initial Stages of Oxidation

This work aims to summarize previous results reported in literature on atomic level properties of the wet chemically treated hydrogen-terminated silicon surfaces and of the Si oxidation, in comparison to a model system of ultraclean Si surfaces prepared in ultrahigh vacuum (UHV) conditions. A literature review shows that a proper wet chemical treatment of Si(111) provides an atomically smooth, high-quality surface, similar to the model template obtained in UHV conditions after high temperature heating. However, it seems that Si(111) is an exception among semiconductor surfaces concerning the effects of wet chemistry. Although the insulator films grown by the atomic layer deposition (ALD) have replaced the thermal oxide of SiO2 in many applications, still an intermediate SiO2 layer is formed and often grown intentionally beneath the ALD film to improve the device performance. However, a detailed atomic structure of the SiO2/Si interface is still debatable, which might be due to differences in atomic level smoothness of the used Si(100) starting surfaces.

Electroluminescence from Silicon-Based Light-Emitting Devices with Erbium-Doped ZnO Films: Strong Enhancement Effect of Titanium Codoping.

We report on the visible and near-infrared electroluminescence (EL) from the light-emitting device (LED) based on the erbium (Er)-doped ZnO (ZnO:Er)/SiO2/n+-Si heterostructure, wherein an ∼10 nm thick SiO2 intermediate layer serves as the energy plateau for producing hot electrons, which come from n+-Si via the trap-assisted tunneling mechanism. These hot electrons excite the doped Er3+ ions by inelastic collision, enabling the Er-related EL from the aforementioned LED. More importantly, by means of codoping the appropriate content of titanium (Ti) into the ZnO:Er film, the aforementioned Er-related emissions can be significantly enhanced. The density functional theory calculations indicate that the Ti-codoping improves rather than degrades the symmetry of the crystal field around the optically active Er3+ ions, hence not increasing the intra-4f transition probabilities of Er3+ ions. However, it is found that Ti-codoping nearly eliminates the segregation of Er3+ ions near the ZnO/SiO2 interface. Moreover, Ti-codoping is derived to result in a number of Zn vacancies, which provide the sites for incorporating Er3+ ions in the ZnO matrix. For the above two reasons, the Ti-codoping promotes the incorporation of optically active Er3+ ions into the ZnO matrix, thus enhancing the EL from the aforementioned LED.

PH‐Responsive Pt@mSiO2@CaP Core–Shell Nanoplatforms for Synergistic Chemo‐ and Photothermal Therapy

AbstractPlatinum/mesoporous silica/amorphous calcium phosphate core–shell nanoplatforms (Pt@mSiO2@CaP) are prepared for near‐infrared light‐triggered photothermal therapy and pH‐responsive chemotherapy. In the core–shell nanoplatforms, the Pt cores with flower‐like shapes exhibit broadband near‐infrared light absorption, which endows the nanoplatforms with a remarkable photothermal performance under 808 nm laser irradiation. The mesoporous SiO2 intermediate layers offer accessible channels for drug loading. The drug release from the SiO2 intermediate layers is driven by the acidic environment of tumor cells owing to the biodegradability of the CaP outermost layer. The hyperthermia generated by the Pt cores accelerates the drug release, thereby increasing intracellular drug concentration. A marked synergistic therapeutic effect of chemo‐ and photothermal therapy in vitro is demonstrated using the DOX‐loaded Pt@mSiO2@CaP. The design of the three‐layer core–shell nanoplatforms points out a way to the synthesis of multifunctional nanomaterials and extends to theranostic applications.

Microfluidics for High Pressure: Integration on GaAs Acoustic Biosensors with a Leakage-Free PDMS Based on Bonding Technology.

Microfluidics integration of acoustic biosensors is an actively developing field. Despite significant progress in “passive” microfluidic technology, integration with microacoustic devices is still in its research state. The major challenge is bonding polymers with monocrystalline piezoelectrics to seal microfluidic biosensors. In this contribution, we specifically address the challenge of microfluidics integration on gallium arsenide (GaAs) acoustic biosensors. We have developed a robust plasma-assisted bonding technology, allowing strong connections between PDMS microfluidic chip and GaAs/SiO2 at low temperatures (70 °C). Mechanical and fluidic performances of fabricated device were studied. The bonding surfaces were characterized by water contact angle measurement and ATR-FTIR, AFM, and SEM analysis. The bonding strength was characterized using a tensile machine and pressure/leakage tests. The study showed that the sealed chips were able to achieve a limit of high bonding strength of 2.01 MPa. The adhesion of PDMS to GaAs was significantly improved by use of SiO2 intermediate layer, permitting the bonded chip to withstand at least 8.5 bar of burst pressure. The developed bonding approach can be a valuable solution for microfluidics integration in several types of MEMS devices.

Fabrication and Optical Characterization of VO2-Based Thin Films Deposited on Practical Float Glass by Magnetron Sputtering and Professional Annealing.

In this paper, VO2 thin films with good optical properties are fabricated on practical float glass by magnetron sputtering and a professional annealing method. The near-infrared switching efficiency (NIRSE) of the prepared film reaches 39% (@2000 nm), and its near-infrared energy modulation ability (ΔTir) reaches 10.9% (780–2500 nm). Further, the highest integral visible transmittance Tlum is 63%. The proposed method exhibits good reproducibility and does not cause any heat damage to the magnetron sputtering machine. The crystalline structure of the VO2 film is characterized by X-ray diffraction (XRD). The lattice planes (011) and (−211) grow preferentially (JCPDS 65-2358), and a large number of NaV2O5 crystals are detected simultaneously. The microstructures are characterized by scanning electron microscopy (SEM), and a large number of long sheet crystals are identified. The phase transition temperature is significantly reduced by an appropriate W doping concentration (Tc = 29 °C), whereas excessive W doping causes distortion of the thermal hysteresis loop and a reduction in the NIRSE. Oxygen vacancies are created by low pressure annealing, due to which the phase transition temperature of VO2 film decreases by 8 °C. The addition of an intermediate SiO2 layer can prevent the diffusion of Na+ ions and affect the preparation process of the VO2 thin film.

A comparative study on the microwave absorption properties of core-single-shell, core-double-shell and yolk-shell CIP/ceramic composite microparticles

In this work, CIP@SiO2, CIP@SiO2@ZrO2 and CIP@void@ZrO2 microspheres were fabricated as model samples of the core-single-shell, core-double-shell and yolk-shell absorbents to systematically compare the role of different coating structures for microwave absorption properties and offer a comprehensive reference to the rational structural design for microwave absorbents. Microstructures, magnetic properties, electromagnetic parameters and microwave absorption of different absorbents were studied. The electromagnetic absorption performance of the as-prepared multicomponent hierarchical microspheres was superior to the sole CIP, owing to the combination of strong magnetic loss of CIP core and excellent dielectric loss of SiO2 and ZrO2 shell. For core-double-shell CIP@SiO2@ZrO2 microspheres, the minimum RL was −20.69 dB at 17.44 GHz with a thickness of 1.7 mm and the effective absorption bandwidth can reach 6.48 GHz at the coating thickness of 2 mm. It is noted that the initial oxidation temperature of CIP increased by ∼200 ℃ owing to the presence of dense SiO2 intermediate layer. Inspiringly, the minimum RL of yolk-shell CIP@void@ZrO2 microspheres was up to −28.38 dB at the absorber thickness of 2.2 mm and the effective absorption bandwidth reach 7.44 GHz from 10.24 to 17.68 GHz at 2.1 mm thickness. The yolk-shell structure had better absorbing performance than the core-shell structure because the cavity as the intermediate layer improved impedance matching. We believed that this work would provide a valuable reference for structural design and optimization of the high-performance absorbing materials.

Vacuum ultraviolet high-reflectance aluminum mirrors on copper substrate for application in noble liquid time projection chamber

Enhancing vacuum ultraviolet reflection at surface of Cu electrode is key to obtain sufficient photon collection efficiency in noble liquid time projection chamber. In this work, MgF2-overcoated Al mirrors is utilized to realize the desired high reflectivity for scintillation photons of liquid xenon at 175 nm. Thermal evaporation technique is explored for the mirror preparation. The Al mirror deposited directly on Cu substrate suffers from severely absorptive and scattering losses and yields 30.3% reflectivity due to the formation of Cu–Al alloy. By prior deposition of a SiO2 intermediate layer on the Cu substrate, the alloy process is prevented and the absorptive loss is suppressed by a factor of 4 approximately. The highest reflectance 82.1% is obtained through optimizing the thickness of the SiO2 intermediate layer. The work holds potential to improve the capability of noble liquid time projection chambers for detection of dark matter and neutrinoless double beta decays.

Gas Permeation Characteristics of TiO2-ZrO2-Aromatic Organic Chelating Ligand (aOCL) Composite Membranes

Methyl gallate (MG) and ethyl ferulate (EF) with a benzene ring were separately used as aromatic organic chelating ligands (aOCLs) to prepare two versions of TiO2-ZrO2-aOCL composite sols via hydrolysis and polycondensation reactions with titanium(IV) isopropoxide (Ti(OC3H7)4) and zirconium(IV) butoxide (Zr(OC4H9)4). Thermogravimetric and FT-IR analysis of dry gels revealed that aromatic rings were present in the residual organic matter when the gel was fired under nitrogen at 300 °C. In X-ray diffraction (XRD) measurements, the TiO2-ZrO2 composite material prepared using these two aOCLs showed an amorphous structure with no crystalline peaks for TiO2 and ZrO2. In N2 adsorption/desorption measurements at 77 K, the TiO2-ZrO2 samples using the aOCLs as a template appeared porous with a larger specific surface area than TiO2-ZrO2 without aOCL. TiO2-ZrO2-aOCL composite membranes were prepared by coating and firing TiO2-ZrO2-aOCL sol onto a SiO2 intermediate layer using an α-alumina porous tube as a substrate. Compared with the TiO2-ZrO2 membrane, the TiO2-ZrO2-aOCL membranes had higher gas permselectivity. The TiO2-ZrO2-EF membrane showed a He permeance of 2.69 × 10−6 mol m−2 s−1 Pa−1 with permeance ratios of He/N2 = 10.6 and He/CF4 = 163, while the TiO2-ZrO2-MG membrane revealed a bit less He permeance at 8.56 × 10−7 mol m−2 s−1 Pa−1 with greater permeance ratios of He/N2 = 61.7 and He/CF4 = 209 at 200 °C. A microporous TiO2-ZrO2 amorphous structure was obtained by introducing aOCL. The differences in the side chains of each aOCL could possibly account for the differences in the microporous structures of the resultant TiO2-ZrO2-aOCL membranes.

Fabrication of 3-Layer Stacked Pixel for Pixel-Parallel CMOS Image Sensors by Au/SiO2 Hybrid Bonding of SOI Wafers

CMOS image sensors have improved their performances including pixel counts, frame rate, and dynamic range to meet the rising demands for high-quality video systems such as 8K/4K television [1] and three-dimensional (3D) imaging. In recent days, 3D integration technologies have been utilized in CMOS image sensor fabrication by using mainly through-silicon vias (TSVs) [2-3]. However, TSVs are shared by plural pixels, thereby preventing fully parallel signal processing to limit sensor performance in conventional stacked sensors. This is because the TSV penetrates the pixel area and it is difficult to be integrated within pixel.To overcome this problem, we have proposed a 3D integration technology without using TSVs but Au/SiO2 hybrid bonding of silicon-on-insulator (SOI) wafers. Stacked layers are electrically connected with Au electrodes integrated in every pixel, which gives pixel-parallel signal processing to image sensor as illustrated in Fig. 1, where Au electrodes are embedded in the SiO2 intermediate layer by the damascene process with chemical mechanical polishing (CMP). The electrode size can be reduced to 1 μm or less in diameter. We previously developed 2-layer stacked pixel-parallel image sensor and showed its wide dynamic range with the ability to capture video images [4-6]. In this paper, we report 3-layer stacked image sensor pixel by extending the 3D integration technology, aiming to shrink the pixel size and to enhance functionality of the pixel-parallel image sensor.Figure 2 shows the fabrication process for the 3-layer stacked CMOS image sensor. The top layer is assigned for photo-detectors and pulse generation circuits, where number of generated pulses are designed to correspond to input illuminance. The middle and bottom layers are for the lower and upper 8-bit pulse counters, respectively. The 3-layer configuration gives every pixel a 16-bit A/D conversion function. The fabrication process flow is as follows: (1) The intermediate SiO2 layers of the top and middle layer equipped with photo detectors or integrated circuits are patterned and etched to form via holes, and the Au electrodes are embedded by electroplating and CMP. (2) The two layers are directly bonded at room temperature mediated with Si thin layer [7]. (3) The handle layer of the middle layer is removed by grinding and XeF2 vapor phase etching, and the backside Au electrodes are formed in the same process as (1). (4) The bottom layer equipped with integrated circuits is then bonded by the same manner as the first bonding, and finally the handle layer of the top layer is removed. By repeating the bonding, electrode forming, and handle layer removing processes, we could obtain multi-layer devices more than three.The cross-sectional SEM image for the developed 3-layer stacked 8-inch wafer is shown in Fig. 3, where no void or separation was observed at the bonded interfaces. The electrode size was 5 μm in diameter with alignment accuracy of as good as 1 μm. Figure 4 shows the measured input-output characteristics of the developed 3-layer stacked pixel. We confirmed linear response of 16-bit digital signal output from pulse counters in middle and bottom layers, which indicates the developed sensor pixel has high bit depth and wide dynamic range with excellent linearity.In summary, a 3-layer stacked pixel for pixel-parallel CMOS image sensor was developed by using hybrid bonding of SOI wafers and embedded Au electrodes. The developed pixel confirmed its pixel-parallel 16-bit A/D conversion operation. Our multi-layer stacked process is promising not only for image sensors with ultimate performances but also various More-than-Moore type devices with multi functions.

Theoretical investigation of cuprous oxide/silicon heterojunction solar cells

Cuprous oxide (Cu2O) based heterojunction solar cells which use Si as n-type layer show promise for high-efficiency conversion and low cost of production. The energetic, electronic, and optical properties of Cu2O/Si heterostructure systems are systematically investigated using GGA and HSE-hybrid density functional theory calculations. The adhesion calculation shows that the Si atoms preferentially bind on top of the O atoms, forming covalent bonds. While the optical properties of Cu2O/Si interface indicate strong absorption. In addition, we have numerically simulated the effects of the intermediate SiO2 layer, which have already been found in experimental evidence, and observed potential reasons for its good photovoltaic performance.

Advantage of SiO2 Intermediate Layer on the Electron Injection for Ti/n-Al0.60Ga0.40N Structure

In this work, and experimentally propose inserting an SiO2 intermediate layer between the Ti and n-AlGaN layer to improve the electron injection efficiency. When the SiO2 intermediate layer is adopted, the SiO2 layer can share a part of the applied voltage and then weakens the surface depletion effect, which is confirmed by the capacitance–voltage measurement. Furthermore, the energy bending of the SiO2 layer pushes the affinity of Ti to be even higher than the conduction band of the Al0.60Ga0.40N layer, which then screens the Schottky barrier and favors the election injection. The influence of the thickness of the SiO2 intermediate layer is also investigated in this work. When the SiO2 layer becomes thick, the tunneling capability of the electrons will be significantly limited due to the increased tunnel region width, leading to increased forward voltage.

Atomic Layer Deposition Assisted Encapsulation of Quantum Dot Luminescent Microspheres toward Display Applications

AbstractQuantum dots (QDs) are promising for being used in advanced displays due to their outstanding emission properties. Herein, a novel encapsulation method for QDs is reported and ultra‐stable QDs@SiO2@Al2O3 luminescent microspheres (QLuMiS) are obtained by combining a sol–gel method for the intermediate SiO2 layer with a fluidized powder atomic layer deposition (ALD) for the outer Al2O3 layer. The rich hydroxyl coverage on the QDs@SiO2 surface provides abundant chemisorption sites, which are beneficial for the deposition of Al2O3 in the ALD process. Simultaneously, the water‐oxygen channels in the SiO2 layer are blocked by the Al2O3 layer, which protects the QDs against deterioration. Consequently, the QLuMiS exhibit an excellent stability with 86% of the initial light conversion efficiency after 1000 h of blue light aging under a light power density of 2000 mW cm−2. Such stability is significantly better than that of QDs@Al2O3 and QDs@SiO2 samples. Moreover, under this strong irradiation aging condition with blue light, the extrapolated lifetime (L50) of QLuMiS is 4969 h, which is ten times longer than that of QDs@SiO2 and is the best record as far as is known. Finally, a prototype of a QLuMiS‐based cellphone screen with a wide color gamut of 115% NTSC is demonstrated.

Plasmon-coupled Charge Transfer in FSZA Core-shell Microspheres with High SERS Activity and Pesticide Detection

A commercial SERS substrate does not only require strong enhancement, but also can be reused and recycled in actual application. Herein, Fe3O4/SiO2/ZnO/Ag (FSZA) have been synthesised, which consisted of Fe3O4 core with strong magnetic field response and an intermediate SiO2 layer as an electronic barrier to keep the stability of magnetite particles and outer ZnO and Ag as the effective layers for detecting pollutants. The SERS enhancement factor (EF) of the FSZA was ~8.2 × 105. The enhancement mechanism of the FSZA core-shell microspheres were anatomized. The electromagnetic enhancement of surface deposited Ag, charge transfer, and molecular and exciton resonances act together to cause such high enhancement factors. For practical application, the FSZA core-shell microspheres were also used to detect thiram, moreover, which was collected and separated by an external magnetic field, and maintained the SERS activity without significant decline during multiple tests. So the good enhancement performance and magnetic recyclability make the FSZA core-shell microspheres a promising candidates for practical SERS detection applications.

Influence of Si and Fe/Cr oxides as intermediate layers in the fabrication of supported Pd membranes

This paper presents for the first time relevant insights on the influence of tuning porous stainless steel (PSS) supports for the preparation of metallic membranes by the Electroless Pore-Plated (ELP-PP) method. Two types of oxides, used as intermediate layer between the support and the Pd layer, were deposited on raw PSS supports for reducing porosity and surface roughness. Both independent and combined routes were considered: (i) Fe2O3-Cr2O3 oxides obtained by direct calcination of the metallic support and (ii) dense and porous SiO2 deposited by dip-coating (DC) technique. Membranes morphology (porosity and surface homogeneity) was characterized by SEM and EDX analysis and gravimetric analysis was used to calculate the total amount of Pd deposited on the external selective layer. Preliminary screening tests suggested that the combined route (calcination followed by DC of SiO2) did not show evident beneficial effects for the preparation of Pd films by ELP-PP. Based on those results, four tubular membranes were fabricated using independent routes: one by calcination and other three by DC, including 1, 2 and 3 layers of SiO2. The first one, including a Fe2O3-Cr2O3 oxides intermediate layer, maintained its mechanical integrity when tested up to ΔP = 4 bar. On the other hand, it was observed that the use of SiO2 intermediate layers noticeably affects the ELP-PP method. Extensive characterization of fresh and used samples has been performed in order to understand the influence of the oxides in the final preparation of a continuous and thin layer of Pd. Results obtained evidenced that the most adequate sample was the support prepared with 2 layers of SiO2 and studies continue to improve membrane stability and to reduce thickness.

Preparation and oxidation behaviour of SiC-based ceramics with TaB2 addition

Liquid-phase-sintered SiC ceramics (LPS-SiC) with the sintering additives of Y2O3–Al2O3 and Y2O3–Al2O3–TaB2 were prepared. The oxidation behaviours of these sintered SiC ceramics were studied after oxidation test at 1300 °C in air. In comparison with SiC ceramicwith Y2O3–Al2O3, the addition of TaB2 inhibited the formation of the secondary phase of Y3Al5O12 (YAG) and homogeneous distribution of Al element in the SiC matrix was evidenced. After oxidation at 1300 °C, SiC ceramic without TaB2 additive was found to possess a two-layer structure within the oxidation region. In contrast, SiC ceramic with TaB2 additive demonstrated the three-layer structure consisting of a dense intermediate layer of SiO2, which could protect the SiC matrix from further oxidation.

Intermediate layer-based bonding techniques for polydimethylsiloxane/digital light processing 3D-printed microfluidic devices

There is profound potential in developing novel microfluidic devices by integrating 3D-printed structures with polydimethylsiloxane (PDMS) to reap the advantages. One important aspect of the successful development of such microfluidic devices is to achieve a uniform and strong bond between PDMS and the 3D-printed structure. In this paper, we present the measurement results of the bonding strength between PDMS and digital light processing 3D-printed structures using intermediate layer-based bonding techniques. Five different intermediate layers were investigated: double-sided tape, a PDMS/tape composite, UV glue, (3-Aminopropyl) triethoxysilane (APTES), and sputter-coated SiO2. A simple burst test structure was designed and fabricated. Out of five available resins from the manufacturer, we chose the yellow resin to compare the bonding strengths with those intermediate layers. The burst test system consisted of a computer-controlled solenoid valve, pressure regulators, and a microscope for inspection. The sputter-coated SiO2 intermediate layer with a thickness of 77 nm demonstrated the highest bonding strength compared to other intermediate layers. The burst pressure with this SiO2 intermediate layer was greater than 436.65 kPa. Furthermore, we measured the burst pressure using the same SiO2 intermediate layer process for two other resins (emerald and black). The burst pressures for these were less than that of the yellow resin. The results indicate that the intermediate layer thickness and oxygen treatment processes have to be optimized for each resin.

TiO2-SiO2-PMMA Terpolymer Floating Device for the Photocatalytic Remediation of Water and Gas Phase Pollutants

Floating photocatalytic devices are highly sought-after as they represent good candidates for practical application in pollutant remediation of large water basins. Here, we present a multilayer floating device for the photocatalytic remediation of contaminants present in water as well as of volatile species close to the water surface. The device was prepared on a novel tailored ter-polymer substrate based on methylmethacrylate, α-methylstyrene and perfluoroctyl methacrylate. The ad hoc synthesized support presents optimal characteristics in terms of buoyancy, transparency, gas permeability, mechanical, UV and thermal stability. The adhesion of the TiO2 top layer was favoured by the adopted casting procedure, followed by a corona pre-treatment and by the deposition of an intermediate SiO2 layer, the latter aimed also at protecting the polymer support from photocatalytic oxidation. The device was characterized by contact angle measurement, UV-vis transmittance and scanning electron microscopy. The final device was tested for the photocatalytic degradation of an emerging water pollutant as well as of vapors of a model volatile organic compound. Relevant activity was observed also under simulated solar irradiation and the device showed good stability and recyclability, prospecting its use for the photocatalytic degradation of pollutants in large water basins.