Transparent Layer Research Articles

Improving the efficiency of thermal insulation of window panes—the use of transparent thin-layer insulation coverings filled with nanostructures

AbstractThe article discusses experimental studies on the thermal conductivity of a transparent thermal insulation layer (film) applied to a window pane. The research was conducted using a measurement cube known as the "Hot Box" method. The examined film was made based on a polymer matrix with metallic inclusions. The insulating layer of the film allows for the transmission and blocking of light—UV infrared radiation. In the studies, a 100 W bulb was used as the source of infrared radiation (light source), placed at the central point of the measurement cube "Hot Box". To estimate the heat transport conditions, temperature distributions on the internal and external surfaces of the examined window pane with the applied transparent coating (film) were measured. Based on the temperature distribution data, the thermal conductivity coefficient of the applied transparent coating on the pane was estimated.

Prediction of Broadband and Highly-Efficient Electromagnetic Wave-Absorbing SiC@SiO2 Nanowire Aerogel by Genetic Algorithm.

Searching for lightweight and high-temperature stable electromagnetic wave-absorbing materials with broad absorbing bandwidth and high efficiency is of significance for applications in daily life and industry. Optimizing the dielectric properties of SiC nanowire aerogel by both compositional and structural designs is an efficient way to obtain simultaneous efficient wave-dissipation ability and good impendence matching and thus the desired properties. However, due to the complex effects of dielectric parameters on the wave-absorbing properties, rational design of high-performance electromagnetic wave-absorbing materials remains challenging. Herein, we propose a genetic algorithm-based approach to predict broadband and highly efficient electromagnetic wave-absorbing materials in a SiC@SiO2 nanowire aerogel-based system. The obtained SiC@SiO2 nanowire aerogels exhibit a gradient multilayered structure with a low dielectric outer layer, a medium layer with alternatively distributed electromagnetic wave transparent and attenuation layers, and an inner high attenuation layer, giving it a broadband electromagnetic wave-absorbing performance covering almost all the 2-18 GHz bandwidth and simultaneous high efficiency. The results show that the genetic algorithm-based approach is efficient in predicting high-performance electromagnetic wave-absorbing ceramic aerogels.

Highly effective passivation of crystalline silicon surfaces achieved through transparent conductive Al-doped ZnO layers

Highly effective passivation of crystalline silicon surfaces achieved through transparent conductive Al-doped ZnO layers

Impulse coupling enhancement of aluminum targets under laser irradiation in a soft polymer confined geometry

Laser pulses were applied to a target mounted on a ballistic pendulum to study the momentum imparted by a laser shock impact. Photonic Doppler Velocimetry was used to assess the momentum imparted by each laser pulse. To increase the momentum produced, a layer of polymer transparent to the laser wavelength was applied to the surface of the targets to confine the plasma generated as a result of the laser–matter interaction. This yielded momentum coupling coefficients one hundred times higher than those obtained for equivalent laser parameters in the classical direct regime configuration. The study was completed by simulating the experiments with the one-dimensional Lagrangian hydrodynamics code ESTHER, which showed good agreement with the experimental results.

Surface plasmon polariton excitation and propagation in metal tripod systems

Through the activation of a planar gaseous medium consisting of four-level tripod atoms, our approach provides a mechanism to generate the Surface Plasmon Polariton (SPP). We investigate a three-layer structure in which the bottom layer is composed of atoms arranged in a tripod configuration, a metal film is layered in the middle, and a transparent layer of either air or vacuum resides on top. The bottom layer facilitates SPP excitation via amplification in the atom arrangement, caused by three laser beams: control, weak probe, and signal. The electromagnetically induced transparency effect, which can be seen in atoms, compensates for the momentum difference between light and SPP. We can coherently change SPP propagation length by altering control field strength, resonance, and off-resonant detuning. SPP optical gain power, propagation length, penetration depth, and metal thickness effects are also examined. Our method to generate SPPs may find use in lithography, sensors, polarizers, along with photodetectors.

Microstructure and topography of laterally confined porous anodic oxides produced with high growth rate in a maskless two-phase jet setup

AbstractMaskless anodic oxidation with a continuous free jet of electrolyte can be used for the local surface functionalization and structuring of aluminum materials. In this study, a two-phase jet was applied with the aim of enhanced lateral confinement of the anodic oxide on the aluminum alloy EN AW-7075. The two-phase jet was realized by a coaxial arrangement. While the inner electrolyte nozzle with a diameter of 100 µm acted as the cathode and was used to provide the electrolyte with a flow rate of 10 ml min−1 resulting in an average jet velocity of approximately 21 m s−1, the outer nozzle with a diameter of 3000 µm was used to provide deionized water with a flow rate of 383 ml min−1 resulting in an average water jet velocity of 1 m s−1, which is sufficient to realize a continuous free two-phase jet. Process voltages from 10 to 60 V were investigated. The realized oxide layers were characterized by non-destructive as well as destructive methods to determine their microstructure and their thicknesses. Optically transparent anodic oxide layers were achieved in the voltage range between 10 and 25 V. Maximum total layer thicknesses between 1.1 µm and 16.9 µm were measured in these cases. Thicknesses of more than 50 µm were determined for higher voltages up to 60 V; however, burning effects and stronger discolorations were determined for voltages ranging from 30 to 60 V. Consequently, 25 V was derived as best suitable voltage for two-phase anodizing with high growth rate leading to oxide layers with low defects. Graphical abstract

Comparison between Compression Strength of Composite Resin with and without Stamp Technique

Background: This study aims to determine whether there is a difference in compression strength between resin composites that use the stamp technique and those that do not use the stamp technique. Objective: To identify the effect of the stamp technique with occlusal matrix on the compression strength and compare it with the one without stamp technique. Materials and methods: This study used an occlusal matrix from a transparent impression made of silicone to print the occlusal teeth. This transparent impression was attached to the resin surface composite prior to polymerization and remained on the surface until polymerization ended. The advantage of using this transparent occlusal matrix is ​​that the light cure can penetrate through the transparent layer of the impression. It can be used to isolate oxygen during polymerization. Results: The average compression strength of composite resin with the stamp technique was 128.5300 ±17.23023 MPa, while composite resin without the stamp technique was 91.2460 ±8,72802 MPa. Conclusion: This study showed the difference between the two test groups, where the resin composite using the stamp strength had a higher compression strength.

Self-Healable Sandfish Scale-Inspired Scalable Triboelectric Layer for Hybrid Energy Harvesting in Desert Environment.

In deserts, sedimentation from frequent dust activities on solar cells poses a substantial technical challenge, reducing efficiency and necessitating advanced cost-inefficient cleaning mechanisms. Herein, a novel sandfish scale-inspired self-healing fluorinated copolymer-based triboelectric layer is directly incorporated on top of the polysilicon solar cell for sustained hybrid energy harvesting. The transparent biomimetic layer, with distinctive saw-tooth microstructured morphology, exhibits ultra-low sand adhesion and high abrasion-resistant properties, inhibits sedimentation deposition on solar cells, and concurrently harvests kinetic energy from wind-driven sand particles through triboelectric nanogenerator (TENG). The film exhibits a low friction coefficient (0.149), minimal sand adhesion force (27 nN), and a small wear area (327 µm2). In addition, over 2 months, a solar cell with the sandfish scale-inspired structure demonstrates only a 16% decline in maximum power output compared to the bare solar cell, which experiences a 60% decline. Further, the sandfish scale-based TENG device's electrical output is fully restored to its original value after a 6-h self-healing cycle and maintains consistent stable outputs. These results highlight the exceptional advantages of employing biomimetic self-healing materials as robust triboelectric layers, showcasing sustained device stability and durability for prolonged use in harsh desert environments, ultimately contributing to a low cost-of-electricity generation paradigm.

Inherited mitochondrial dysfunction triggered by OPA1 mutation impacts the sensory innervation fibre identity, functionality and regenerative potential in the cornea

Mitochondrial dysfunctions are detrimental to organ metabolism. The cornea, transparent outmost layer of the eye, is prone to environmental aggressions, such as UV light, and therefore dependent on adequate mitochondrial function. While several reports have linked corneal defects to mitochondrial dysfunction, the impact of OPA1 mutation, known to induce such dysfunction, has never been studied in this context. We used the mouse line carrying OPA1delTTAG mutation to investigate its impact on corneal biology. To our surprise, neither the tear film composition nor the corneal epithelial transcriptomic signature were altered upon OPA1 mutation. However, when analyzing the corneal innervation, we discovered an undersensitivity of the cornea upon the mutation, but an increased innervation volume at 3 months. Furthermore, the fibre identity changed with a decrease of the SP + axons. Finally, we demonstrated that the innervation regeneration was less efficient and less functional in OPA1+/- corneas. Altogether, our study describes the resilience of the corneal epithelial biology, reflecting the mitohormesis induced by the OPA1 mutation, and the adaptation of the corneal innervation to maintain its functionality despite its morphogenesis defects. These findings will participate to a better understanding of the mitochondrial dysfunction on peripheral innervation.

Recent Advancements on Slot-Die Coating of Perovskite Solar Cells: The Lab-to-Fab Optimisation Process

Perovskite solar cells (PSCs) are the most rapidly advancing photovoltaic technology in terms of power conversion efficiency. An efficiency of 26.1% was achieved in a decade, which is on par with the efficiency of very mature silicon panels. However, PSC commercialisation is partly hindered by the difficulty of scaling these devices without efficiency loss, mostly due to the increasing sheet resistance of the transparent conductive layer substrates and the nonuniformity of the layers when deposited across large areas. Therefore, it is crucial for the commercialisation of PSCs to implement easily scalable deposition processes with low material waste and compatibility with roll-to-roll (R2R) processes to reduce manufacturing costs. Slot-die coating can meet all these requirements, allowing for great uniformity over large areas. The most recent developments in PSC upscaling using slot-die coating as the main deposition process, along with its extension to the R2R process, are reviewed, including a thorough discussion of the slot-die coating process and the theory behind its operating limits. In fact, R2R coating is a very promising strategy for PSC industrialisation, since all processing steps use low-cost materials and scalable processes at temperatures lower than 120 °C, allowing the cost-effective and high-throughput production of PSC devices.

Eco-friendly activation of cotton textiles with LiNbO3 nanoparticles for enhanced self-cleaning and antibacterial performance

Cotton textiles play a universal role in everyday life, but they are prone to stain and serve as a primary channel for transmitting viruses and bacteria. The photocatalytic/antibacterial coatings are highly effective in addressing bacterial contamination on fabrics, although their efficacy diminishes with continuous use and washing. Here, insights are provided into the attachment of LiNbO3 on cotton surfaces using eco-friendly chemical activators to promote resistance to washing cycles, self-cleaning, and bactericide textiles. LiNbO3 nanoparticles were synthesized by low-temperature hydrothermal synthesis and directly applied to cotton fabric using immersion. The synthesized nanoparticles were characterized by X-ray diffraction (XRD), Brunauer-Emmett-Teller (BET) N2 adsorption, diffuse reflectance for band gap determination, and Raman spectroscopy. A simple and effective impregnation method was used, promoting an ester-bond attachment between the cotton surface and the activators. Microscopy analysis (SEM) confirmed the successful deposition of the nanoparticles on cotton fabric. The LiNbO3 coating consisted of transparent layers and did not change the properties of cotton. Methylene blue stains are generally eliminated under UV light after 2 h using nanoparticles and activators. Antibacterial properties were evaluated under visible light through direct contact with bacterial suspensions and culturing. The coated cotton fabric that was activated with oxalic acid exhibited significant photocatalytic antibacterial activity against both Escherichia coli (gram-negative) and Staphylococcus aureus (gram-positive) bacteria, with bacterial reduction rate above 97 %, even after 10 washing cycles. This performance can be attributed to the effective coupling of LiNbO3 with oxalic acid in the cotton’s surface and its resistance to washing out. This study's novel synthesis and coating method offers an environmentally friendly, cost-effective, and straightforward approach for producing LiNbO3 self-cleaning and antibacterial surface-activated cotton.

Influence of global/local processing on perceived colour transparency.

Our cognitive processing is flexible and affected by global/local dominance in prior cognitive tasks. Similar to cognitive processing, perceptual processing, especially colour perception related to global/local processing, may be affected by prior global/local dominance; however, this possibility has not yet been assessed. Here, we examined whether prior tasks involving global/local processing influenced colour perception related to global/local processing. As colour perception is related to global/local processing, we focused on perceived colour transparency, in which a transparent layer is perceived in front of a background layer, even though these stimuli are physically in the same layer. When viewing the colour transparency stimulus, we expected that the perceived colour of a specific region, when focusing on only the local region, would differ from that when focusing on the whole image. In our study, the participants completed a global or local Navon task, followed by a colour-matching task that assessed how they saw colours using colour transparency stimuli. The degree of optical illusion (i.e., perceived colour transparency) after the global Navon task was greater than that after the local Navon task. Thus, prior global/local processing, a flexible mode of cognitive processing, influenced colour perception. This study provides new insight into perceptual flexibility, especially in colour perception.

Comparative study of cadmium telluride solar cell performance on different TCO‐coated substrates under concentrated light intensities

AbstractConcentrating photovoltaics is an attractive route for achieving high power output with thin film solar cells, using low‐cost optics. In this work, the performance of CdTe:As thin film solar cells on two different transparent conducting oxide (TCO)‐coated substrates is investigated and compared under varying concentrated light intensities (1–6.3 Suns). Samples tested had CdZnS/CdTe:As devices deposited atop of either a soda‐lime glass with a fluorine‐doped tin oxide TCO or an ultra‐thin glass (UTG) with an aluminium zinc oxide TCO and ZnO high‐resistive transparent (HRT) layer. Device current density was found to increase linearly with increased light intensities, for both sample configurations. Power conversion efficiencies of both device samples decreased with increased light intensity, due to a decrease in fill factor. The fill factor, for both sample configurations, was affected by reducing shunt resistance with increasing illumination intensity. The two device types performed differently at the high illumination intensities due to their series resistance. Light‐soaking devices under 6.3 Suns illumination intensity for 90 min showed no significant performance degradation, indicative of relatively stable devices under the highest illumination intensity tested. Efficiency limiting factors are assessed, evaluated and discussed.

Transparent Image Layer Diffusion using Latent Transparency

We present an approach enabling large-scale pretrained latent diffusion models to generate transparent images. The method allows generation of single transparent images or of multiple transparent layers. The method learns a "latent transparency" that encodes alpha channel transparency into the latent manifold of a pretrained latent diffusion model. It preserves the production-ready quality of the large diffusion model by regulating the added transparency as a latent offset with minimal changes to the original latent distribution of the pretrained model. In this way, any latent diffusion model can be converted into a transparent image generator by finetuning it with the adjusted latent space. We train the model with 1M transparent image layer pairs collected using a human-in-the-loop collection scheme. We show that latent transparency can be applied to different open source image generators, or be adapted to various conditional control systems to achieve applications like foreground/background-conditioned layer generation, joint layer generation, structural control of layer contents, etc. A user study finds that in most cases (97%) users prefer our natively generated transparent content over previous ad-hoc solutions such as generating and then matting. Users also report the quality of our generated transparent images is comparable to real commercial transparent assets like Adobe Stock.

Noise analysis and optical response of microwave kinetic inductance detectors with an optical stack

We report on the experimental investigation of optical coupling for superconducting microresonators known as microwave kinetic inductance detectors (MKIDs) in the visible and near-infrared bands. MKIDs are photon-counting, time and energy-resolving detectors that still suffer from a poor quantum efficiency. To improve this efficiency, we propose to add a superconducting reflective layer below the absorbing part of the detector separated by a transparent Al2O3 layer with a quarter-wavelength thickness optimized around a single wavelength λ = 405 nm. We have first fabricated samples patterned from stoichiometric TiN ( Tc∼4 K), one with the full optical stack, one without for reference and one with a partial optical stack in order to characterize the noise influence of each layer individually. We observe that the full optical stack geometry has the most impact on the resonator’s noise and quality factors. A second design was fabricated to characterize the optical response to short pulses of the optical stack and we show from both the frequential noise and optical response that a strong signature of TLS is still present in the optical stack sample. We have finally obtained single-photon response with the optical stack using a more sensitive tri-layer TiN/Ti/TiN absorber ( Tc∼1.3 K) for which a maximum energy resolving power of R=E/ΔE∼ 1.3 was achieved using 405 nm laser pulses at 225 mK. The quality factors of both the reference and optical stack samples are similar but the frequency noise is still a tenfold higher for the optical stack sample which degrades the energy-resolving power of the detector.

Transparent superhydrophilic acrylic resin@GO-Fe3O4 coatings for glass surfaces with highly efficient visible-light-induced self-cleaning and anti-fogging properties

A transparent layer containing acrylic resin, graphene oxide and Fe3O4 have been studied based on its potential application including photocatalytically active and self-cleaning coatings. In this study, a transparent and superhydrophilic acrylic resin@graphene oxide-Fe3O4 (PA@GO-Fe3O4) composite coating has been successfully deposited on a glass substrate by dip coating technique to provide a thin film with a self-cleaning and photocatalytically active surface. The prepared samples were characterized by field emission scanning electron microscope (FE-SEM), atomic force microscope (AFM), fourier transform infrared (FTIR), X-ray diffraction (XRD), Raman spectroscopy, UV–vis diffused transmittance (DTS) and water contact angle (WCA) measurements. The photocatalytic activity of the coated surfaces was investigated by the photocatalytic degradation of methylene blue (MB) under UV and visible light irradiation. The glass film of PA@GO-Fe3O4 (5 %) with an average roughness of 20.71 nm exhibited 76 % and 72 % MB photodegradation efficiency for 450 min under UV and visible light illuminations. The transparency of the glass coated film decreased to 76 % relative to that of the non-coated bare glass (92 %). The hydrophilicity of the glass coated film facilitated the formation of a thin water layer, which can increase self-cleaning property of glass coated film and augment the anti-fog effect. Therefore, the PA@GO-Fe3O4 composite coating exhibits significant superhydrophilicity, self-cleaning, and antifogging properties.

Transparent Luminescent down-conversion coating for improved performance and enhanced stability of carbon-based perovskite solar cells

Methylammonium lead halide-based perovskite solar cells (PSCs) perform superior photovoltaic performance, nevertheless, demonstrate limited light utilization and instability within the ultraviolet (UV) range. Lanthanide-based down-conversion (DC) materials can mitigate the photoinduced deterioration by resolving spectrum mismatched losses. Particularly, lanthanide complexes possess a broad UV absorbing region thus can convert absorbed UV light to visible or near-infrared light, exhibiting large pseudo-Stoke's shift while they could allow spectrum responsiveness of the PSCs in the UV.Therefore, the DC material may enhance the photovoltaic performance by converting high-energy photons to low-energy photons whilst may also perform as UV shielding material, and finally may both develop PSCs' efficiency and stability. Herein, a novel transparent luminescent down-converting layer (LDC) based on a highly emitting Europium complex in a siloxane matrix was used as an external coating to PSCs with the purpose of improving the solar cells' performance extending their response in the UV region while improving cells’ photostability. The conducted studies indicated that the LDC coating may additionally serve as an anti-reflective and UV-shielding layer simultaneously, resulting in better light-harvesting ability of the perovskite. As a result, short circuit current (Jsc) amplification by the presence of LDC re-emitting the absorbed UV light to the visible and the best carbon-based perovskite solar cell (C-PSC) revealed a 16.13 % overall performance in comparison to the 15.38 % obtained for the control device. Furthermore, photostability tests demonstrated that the unencapsulated LDC-modified devices prepared under ambient conditions retained 75 % of their initial PCE after 8 h under artificial solar light illumination whereas the control devices remained at 40 % at the same conditions. These findings suggest that the LDC layer decreases the UV degradation for PCEs, resulting in PCE and stability enhancement.

Optical constants and thickness gradients for light intensities in glass substrate layers and for complex electric fields in indium tin oxide (ITO) transparent conductor thin film layer, using Bode and Nyquist wavelength-dependent diagrams

Abstract The optical constants of a thin film layer of transparent conductive indium tin oxide (ITO), deposited on a thick glass substrate (G), were obtained for an ITO-G sample using a multilayer matrix method by fitting the regular transmittance and specular reflectance measurements to the collimated equations of the four-flux model, once the optical constants of the glass substrate layer had previously been obtained from a G sample of a single glass substrate layer. The accuracy of the results was validated using a feedback system called the three-extinction matching requirement, that is, obtaining the same extinction coefficients from the optical constants and from the forward and backward collimated differential equations of the four-flux model. To calculate the extinction coefficients of the glass from optical constants, the compression of the wavelength of the incident light in the glass substrate and in the thin ITO film layer was demonstrated, with a thickness less than the wavelength of incident light. The thickness gradients of the forward and backward collimated light intensities, on the glass substrate of the ITOG sample, were compared with those obtained for the single-layer G sample. Then, the thickness gradients for the complex forward and backward electric fields of the ITO thin film layer were obtained and plotted using spectral magnitude and phase Bode plots and new Nyquist plots, i.e. imaginary versus real parts, dependent on wavelength.

Factors associated with the quality of corneas retrieved for transplantation by Eye Banks: a scoping review protocol

IntroductionThe cornea is an avascular and transparent layer of connective tissue crucial to retinal image quality. Diseases can impair its quality, affecting vision. Keratoplasty is the only therapy capable of...

Development of carbon dots‐immobilized fluorescent polylactic acid hydrogel ink toward security authentication

AbstractA self‐healable hydrogel for advanced authentication applications was successfully developed. In the presence of an aqueous solution of ammonium hydroxide as a cheap passivating agent, the hydrothermal carbonization of cellulose diacetate extracted from rice straw yielded nitrogen‐doped carbon dots (NdCD) in a straightforward and ecologically beneficial manner. NdCD achieved a maximum quantum yield of 25.11%. Self‐healing biocomposite inks with different emission properties were created by using different concentrations of NdCD nanoparticles (NPs). In order to create a transparent layer of NdCD@PLA hydrogel, stamps were used to press homogenous films onto paper surfaces. Polylactic acid (PLA) hydrogel was embedded with NPs of NdCD. Self‐healing security hydrogel inks are highly durable. The NdCD@PLA hydrogel is efficiently self‐healable at room temperature. The current NdCD@PLA hydrogel can attach to different surfaces, such as glasses, plastics, and papers. The self‐healable nanobiocomposite was photostable when exposed to UV light. Under UV light, NdCD‐containing nanobiocomposite inks have a bluish color, as proved by both colorimetric parameters and fluorescence spectra. The morphological properties of NdCD were studied by transmission electron microscopy to suggest a particle diameter of 10–15 nm. The morphology of the fluorescent prints was analyzed using a number of different analytical methods. The hydrogel rheology and the mechanical performance of printed papers were tested. The printed films showed excitation and fluorescence bands at 401 and 488 nm, respectively. The present smart ink shows significant promise as a potential industrial production technique to simply produce anti‐counterfeiting prints.Highlights Rice straws were used to prepare nitrogen‐doped carbon dots with a quantum yield of 25.11%. Self‐healable polylactic acid hydrogel was immobilized with N‐doped carbon dots (10–15 nm). Transparent printed films shifted in color to blue (488 nm) when excited at 401 nm. Ultraviolet‐stimulated photochromic authentication prints were prepared. Printed paper demonstrated non‐cytotoxicity, high photostability, and durability.