Transparent Materials Research Articles

Electronic and optical properties for Li1-xAgxAlTe2 alloys: potential transparent conductive material

Using the hybrid functionals combining the special quasi-random structure methods, the properties of LiAlTe2, AgAlTe2, and their alloys (Li1-xAgxAlTe2) are studied. Our study confirms that both LiAlTe2 and AgAlTe2 are direct wide-band gap semiconductors. Moreover, LiAlTe2 possesses high transmittance in the visual light region. Lattice constants and volume of Li1-xAgxAlTe2 alloys satisfy Vegard’s law. The band gaps express nonlinear behavior with the component x, and the optical bowing parameter (b Eg ) is 0.13. The carriers’ effective mass for Li1-xAgxAlTe2 alloys is rapidly decreased by the presence of Ag. When Ag component reaches 0.125, the electron (hole) effective mass is 0.225 (0.271) m0 (m0: static electron’s mass), and the band gap is 3.034 eV. Low transition temperature suggests Li1-xAgxAlTe2 alloys are stable under experimental conditions. Meanwhile, the Li1-xAgxAlTe2 alloys express excellent ductility, which is beneficial for future flexible device applications. Wide band gap, smaller electron (hole) effective mass, thermodynamic stability, and high transmittance in the visual light region indicate Li0.875Ag0.125AlTe2 alloy is a promising transparent conductive material.

Mn2+/Er3+‐Codoped Cs2AgInCl6 Double Perovskites with Dual Emission and Photochromism Properties for Anti‐Counterfeiting Application

AbstractHighly transparent inorganic photochromic materials have several promising applications, especially for anti‐counterfeiting application. Enriching and enhancing the luminescent properties of perovskite by doping transition metals and rare earth elements into the host is a feasible and attractive route. Codoping of Mn2+ and Er3+ can realize novel anti‐counterfeiting properties with upconversion emission and photochromic ability within a double perovskite structure of Cs2AgInCl6.The Cs2AgInCl6: Mn2+, Er3+ single crystal can be observed in a reversible color variation from yellow to dark violet by implementing under 365, 520 nm illumination or thermal treatment. In addition, the crystal emits red and green light under the excitation of 365 nm ultraviolet and 980 nm laser, respectively. The introduction of Mn2+ endowed Cs2AgInCl6 with photochromic ability, and Mn2+ acted as a bridge for energy transfer from host excitons to Er3+, facilitating emission in the visible region. Er3+ achieve upconversion luminescence in the material through its abundant energy levels and acting synergistically with Mn2+. Herein, the Cs2AgInCl6:Mn2+, Er3+ combines various optical properties and has applications for specific anti‐counterfeiting demands.

Indirect Liftoff Mechanism for High‐Throughput, Single‐Source Laser Scribing for Perovskite Solar Modules

AbstractA high‐throughput, single‐source laser scribing method exploiting a transparent conducting oxide (TCO) indirect liftoff mechanism is developed to produce serially interconnected perovskite solar modules. The TCO‐based indirect liftoff mechanism relies solely on laser absorption in the front transparent electrode material reducing thermal damage to the overlying layers and allowing for fast scribing speeds with low‐cost μs‐pulse duration fiber laser systems. Minimal resistive power losses are observed with the method compared to conventional ablative laser scribes, maintaining the power conversion efficiencies of small‐area devices (≈0.2 cm2) across significantly larger deposition areas (≈1 cm2). Demonstrating > 3 m s−1 processing speeds, TCO‐based liftoff provides the highest throughput laser scribing method for thin‐film photovoltaic devices produced on glass/TCO substrates, capable of processing large‐area perovskite solar modules at a manufacturing scale.

Stretchable Substrates with 3D Wave Patterned Surface for Enhanced Mechanical Stability of Indium Tin Oxide Electrodes

AbstractFlexible electronic devices have promising applications in many future technologies such as wearables, implantables, robotics, and displays. Among the distinct types of mechanical flexibility, stretchability stands as a significant challenge. A particularly demanding objective is the realization of a high‐performance transparent electrode that endures stretching and can be mass produced, all while avoiding additional restrictions on device density. In this work, it is demonstrated that a 3D wave patterned surface provides a threefold improved strain performance of deposited indium tin oxide electrodes, in a statistical comparison of 3D wave patterned and planar surfaces, where indium tin oxide electrodes are stretched to electrical failure. Moreover, this platform alleviates residual thin film stress, allowing for easier handling of the substrates. This study demonstrates the feasibility of attaining stretchability for upcoming electronic devices using a scalable platform that incorporates high‐performance transparent electrode materials using only conventional materials and fabrication steps.

Simultaneous Enhancement of Thermal Insulation and Impact Resistance in Transparent Bulk Composites.

Transparent bulk glass is highly demanded in devices and components of daily life to transmit light and protect against external temperature and mechanical hazards. However, the application of glass is impeded by its poor functional performance, especially in terms of thermal isolation and impact resistance. Here, a glass composite integrating the nacre-inspired structure and shear stiffening gel (SSG) material is proposed. Benefiting from the combination of these two elements, this nacre-inspired SSG/glass composite (NSG) exhibits superior thermal insulation and impact resistance while maintaining transparency simultaneously. Specifically, the low thermal conductivity of the SSG combined with the anisotropic heat transfer capability of the nacre-inspired structure enhances the out-of-plane thermal insulation of NSG. The deformations over large volumes in nacre-inspired facesheets promote the deformation region of the SSG core, synergistic effect of tablet sliding mechanism in nacre-inspired structure and strain-rate enhancement in SSG material cause the superior impact resistance of overall panels in a wide range of impact velocities. NSG demonstrates outstanding properties such as transparency, light weight, impact resistance, and thermal insulation, which are major concerns for the application in engineering fields. In conclusion, this bioinspired SSG/glass composite opens new avenues to achieve comprehensive performance improvements for transparent structural materials.

Hierarchically Structured 3D Nanoporous Vanadium Oxide Transparent Electrodes for Next‐Generation Supercapacitors

AbstractThis article describes the automatic spray pyrolysis deposition (ASPD) process for the synthesis of hierarchically structured 3D nanoporous vanadium oxide (V2O5) transparent material on a fluorine‐doped tin oxide (FTO) substrate. The deposition of material occurs at 673 K using an aqueous solution of NH4VO3, with a constant solution spray rate of 10 mL min−1 and airflow rate of 10 L min−1. Structural analysis confirms the pure orthorhombic structure formation of the V2O5 material, while FE‐SEM images show a well‐organized 3D spongy‐like porous architecture. The excellent conformality of the ASPD enables the deposition of high‐aspect‐ratio 3D structured nanoporous V2O5 electrodes for next‐generation supercapacitor applications. The hierarchical structured 3D nanoporous V2O5 electrode exhibits superior electrochemical performance in a 1M Na2SO3 electrolyte. Within the potential window 0 to ‐1.3 V, the electrode archives the highest specific capacitance (SC) of 453.32 F g−1 and also retains 86% of its capacitance after 5000 cycles. These properties mainly originate from the crystallinity, 3D nanoporous structure, and fast and easy ionic intercalation through the material. Furthermore, a symmetric supercapacitor device using this electrode is fabricated and which yields outstanding electrochemical performance. Overall, the results highlight the potential of 3D nanoporous V2O5 as an outstanding electrode material for next‐generation supercapacitor applications.

ELECTRICAL, OPTICAL, AND CHEMICAL PROPERTIES OF GRAPHENE THIN FILMS FABRICATED BY VACUUM FILTRATION TECHNIQUE

There has been considerable interest in graphene as a transparent electrode material because of its extraordinary features, such as high optical transmittance, high electrical conductivity, excellent thermal conductivity, exceptional mechanical strength, and remarkable electrochemical capacity. In addition, transparent conductors’ graphene thin films have been considered a promising candidate to replace currently utilized indium tin oxide films, which are unlikely to meet future demands because of their rising cost. In this study, a vacuum filtration process along with isopropyl alcohol (IPA)-assisted with direct transfer (IDT) technique is used to prepare wide-area highly conductive graphene thin films on different substrates including (glass, and PET). The graphene thin films' optical, structural, and electrical properties are studied. The graphene sheets are deposited homogeneously on the substrate, and the distribution of small graphene sheets is observed in SEM images. XPS analysis revealed that the amount of oxygen in graphene decreases significantly with annealing at 500°C and treated with HNO3. Furthermore, the graphene transparent conductive films prepared by the adjusted vacuum filtration method show low sheet resistances of 12.2, 1.41, 1.18, and 0.8 kΩ/sq with transmittances of 81%, 70%, 64.3%, and 46.4% respectively after being annealing at 500°C and treated with HNO3.

Using electrical impedance spectroscopy to identify equivalent circuit models of lubricated contacts with complex geometry: In-situ application to mini traction machine

Electrical contact resistance or capacitance as measured between a lubricated contact has been used in tribometers, partially reflecting the lubrication condition. In contrast, the electrical impedance provides rich information of magnitude and phase, which can be interpreted using equivalent circuit models, enabling more comprehensive measurements, including the variation of lubricant film thickness and the asperity (metal-to-metal) contact area. An accurate circuit model of the lubricated contact is critical as needed for the electrical impedance analysis. However, existing circuit models are hand derived and suited to interfaces with simple geometry, such as parallel plates, concentric and eccentric cylinders. Circuit model identification of lubricated contacts with complex geometry is challenging. This work takes the ball-on-disc lubricated contact in a Mini Traction Machine (MTM) as an example, where screws on the ball, grooves on the disc, and contact close to the disc edge make the overall interface geometry complicated. The electrical impedance spectroscopy (EIS) is used to capture its frequency response, with a group of load, speed, and temperature varied and tested separately. The results enable an identification of equivalent circuit models by fitting parallel resistor-capacitor models, the dependence on the oil film thickness is further calibrated using a high-accuracy optical interferometry, which is operated under the same lubrication condition as in the MTM. Overall, the proposed method is applicable to general lubricated interfaces for the identification of equivalent circuit models, which in turn facilitates in-situ tribo-contacts with electric impedance measurement of oil film thickness – it does not need transparent materials as optical techniques do, or structural modifications for piezoelectric sensor mounting as ultrasound techniques do.

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This paper proposes the first self-supervised 6D object pose prediction from multimodal RGB + polarimetric images. The novel training paradigm comprises (1) a physical model to extract geometric information of polarized light, (2) a teacher–student knowledge distillation scheme and (3) a self-supervised loss formulation through differentiable rendering and an invertible physical constraint. Both networks leverage the physical properties of polarized light to learn robust geometric representations by encoding shape priors and polarization characteristics derived from our physical model. Geometric pseudo-labels from the teacher support the student network without the need for annotated real data. Dense appearance and geometric information of objects are obtained through a differentiable renderer with the predicted pose for self-supervised direct coupling. The student network additionally features our proposed invertible formulation of the physical shape priors that enables end-to-end self-supervised training through physical constraints of derived polarization characteristics compared against polarimetric input images. We specifically focus on photometrically challenging objects with texture-less or reflective surfaces and transparent materials for which the most prominent performance gain is reported.

Retracted: Detecting Distance between Surfaces of Large Transparent Material Based on Low-Cost TOF Sensor and Deep Convolutional Neural Network

Retracted: Detecting Distance between Surfaces of Large Transparent Material Based on Low-Cost TOF Sensor and Deep Convolutional Neural Network

The transparency and p-type defects for group IV atoms doped AlP: the hybrid functional study

Abstract The electronic structures and optical properties, together with the properties for intrinsic defects and group IV atoms doped AlP are studied by employing the hybrid functional method. Obtained results imply AlP is a promising transparent material, nonstoichiometric AlP is a potential n-type semiconductor. The transition energy level ε(0/-) for C, Si and Ge substituting P are 0.24, 0.33 and 0.48 eV above the valence band maximum (VBM), indicating C substituting P (written as CP) is a shallow p-type defect. With the thermal equilibrium fabricated method, the obvious self-compensation effect exists among the CP and the intrinsic defects, suggesting the non-equilibrium fabricated method, such as, the molecular beam epitaxy fabrication scheme, should be considered to fabricate the p-type CP defect.

Polypropylene nanocomposites produced by in‐situ grafting of maleic anhydride using different mixing procedures

AbstractNanocomposites (NC) of polypropylene (PP) and organophilic montmorillonite (oMt) are produced by reactive mixing with simultaneous grafting of maleic anhydride (MA) onto PP using organic peroxide as initiator. Five different strategies of incorporating reactants and clay into a laboratory mixer are used. The structure of composites is examined by FT‐IR spectroscopy, x‐ray diffraction and scanning electron microscopy. Rotational rheometry, thermogravimetry and oxygen permeability are used to evaluate properties. The preparation method has a remarkable influence on NC's structure. Simultaneous addition of peroxide and MA to molten PP followed by incorporation of clay 20 minutes later produces the best degree of clay exfoliation/disaggregation. The NCs obtained using this procedure are highly transparent and have very thin tactoids with interlayer spacing more than 50% larger than the original oMt. The incorporation of just 2 wt% of clay gives place to more than 30% reduction in PP oxygen permeability. Additionally, the temperature at the maximum thermal degradation rate in nitrogen reduces in about 60°C while the temperature at which the thermal degradation process begins is not affected.Highlights Highly intercalated/exfoliated PP/oMt nanocomposites are synthesized Reactive mixing procedure affects the quality of nanocomposite's structure A initial period of grafting before clay addition is the most effective method Highly transparent materials with small tactoids of d001>4 nm is generated PP oxygen permeability is highly reduced by the use of just 2 wt% of nanoclay

Machine learning-assisted high-throughput screening of transparent organic light-emitting diode anode materials

A target-driven material design framework for the rapid work function prediction of AB-type 2D nanomaterials is proposed to accelerate the discovery of transparent OLED anode materials.

A Single-Frame Deflectometry Method for Online Inspection of Light-Transmitting Components.

Transparent materials are widely used in industrial applications, such as construction, transportation, and optics. However, the complex optical properties of these materials make it difficult to achieve precise surface form measurements, especially for bulk surface form inspection in industrial environments. Traditional structured light-based measurement methods often struggle with suboptimal signal-to-noise ratios, making them ineffective. Currently, there is a lack of efficient techniques for real-time inspection of such components. This paper proposes a single-frame measurement technique based on deflectometry for large-size transparent surfaces. It utilizes the reflective characteristics of the measured surface, making it independent of the surface's diffuse reflection properties. This fundamentally solves the issues associated with signal-to-noise ratios. By discretizing the phase map, it separates the multiple surface reflection characteristics of transparent devices, enabling transparent device measurement. To meet the requirements of industrial dynamic measurement, this technique only needs a simple and low-cost system structure, which contains just two cameras for image capture. It does not require phase shifting to complete the measurement, making it independent of the screen and having the potential for larger surface measurement. The proposed method was used to measure a 400mm aperture automobile glass, and the results showed that it is able to achieve a measurement accuracy on the order of 10 μ m. The method proposed in this paper overcomes the influence of surface reflection on transparent objects and significantly improves the efficiency and accuracy of large-sized transparent surface measurements by using a single-frame image measurement. Moreover, this method shows promise for broader applications, including measurements of lenses and HUD (Heads-Up Display) components, showcasing significant potential for industrial applications.

Effectiveness of palpation technique training and practice using a muscle-nodule-palpation simulator.

[Purpose] Extant techniques for palpating nodules, a diagnostic criterion of myofascial trigger points, lack high reliability. Therefore, this study aimed to investigate the effects of training and practice using a novel muscle-nodule-palpation simulator. [Participants and Methods] Sixteen university students (age range: 19-22 years) were randomly assigned to the training (n=8) and control (n=8) groups and used the muscle-nodule-palpation simulator to determine the position and orientation of the muscle nodule embedded in the model. During the experiment, only the participants in the training group were allowed to practice nodule detection while viewing the model through its transparent material. Subsequently, both groups underwent a performance evaluation. [Results] The training group exhibited greater improvement in performance than the control group. The means and standard errors of the improvement in the proportion of successful localization of the muscle nodule were 0.14 ± 0.06 for the control group and 0.42 ± 0.09 for the training group. [Conclusion] Training using the muscle-nodule-palpation simulator improved palpation technique for nodule localization.

FABRICATION OF REALISTIC TRANSPARENT POROUS MEDIA FOR 3D OBSERVATION OF INTERNAL MASS TRANSPORT

A new experimental system was developed to observe the migration of colloidal particles in saturated porous media in 3D, which is important in engineering processes such as contaminant migration and filtration. The system enables the observation of internal migration that is invisible from the outside by fabricating a porous body using a transparent material and a 3D printer. Non-artificial media with arbitrarily controlled internal pore sizes were fabricated by designing the porous media based on the results of numerical analysis on phase-separation phenomena. The refractive indices of the porous media and the interstitial liquid were matched, and a laser sheet was used to extract cross sections of the media. By reconstructing multiple cross-sectional images, it was possible to visualize the 3D migration of suspended particles. The developed system was then applied to the collective gravitational settling of fine particles in saturated porous media. The results showed that the particles selectively settled in the pore networks while repeatedly branching in the lateral direction.

Direct observation of carbon slurry flow behavior and its effect on electrochemical performance in a microfluidic electrochemical flow capacitor.

Carbon slurries have been used as "flowable electrodes" in various electrochemical systems, and the slurry flow characteristics play an important role in the system electrochemical performance. For example, in an electrochemical flow capacitor (EFC), activated carbon particles must pass electrical charge from a stationary electrode to surrounding particles via particle-electrode and particle-particle interactions to store energy in the electric double layer. So far, particle behaviors under a continuous flow condition have not been observed due to the slurry's opacity, and studies of the device's performance thus have been mainly on a bulk level. To understand the relation between the hydrodynamic behavior and the electrochemical performance of carbon slurries, we have constructed a microfluidic EFC (μ-EFC) using transparent materials. The μ-EFC allows for direct observation of particle interactions in flowing carbon slurries using high-speed camera recording, and concurrent measurements of the electrochemical performance via chronoamperometry. The results indicate an interesting dependence of the particle cluster interaction on the flowrate, and its effect on the slurry charging/discharging behavior. It is found that an optimal flowrate could exist for better electrochemical performance.

Achieving lysozyme functionalization in PDADMAC-NaPSS saloplastics through salt annealing.

Hot-pressed saloplastics are dense and transparent polyelectrolyte complex materials governed by ionic crosslinking. Such plastics have several advantages, for example, salt water processibility and recyclability. Here, we demonstrate a simple but effective post-treatment method to incorporate lysozyme as a biocatalytic component into the hot-pressed saloplastics. Changes in salt concentration can be used for annealing and curing the saloplastics, where the temporary opening allows for lysozyme loading. This process was carefully examined by two different routes and the salt concentrations and incubation times were varied systematically. Optimised saloplastics showed an enzymatic activity against Micrococcus lysodeikticus of 4.44 ± 0.37 U cm-2 and remained partially active (∼72% activity preserved) after 7 days. This approach opens new routes to incorporate enzymes or other biological functionality into saloplastics which is difficult to achieve for conventional plastics.

Low reflective index, highly transparent, and ultra-low dielectric constant materials prepared via effective copolymerization of 4-methyl-1-pentene and a Si-containing α,ω-diolefin

A series of ultra-low dielectric constant materials containing C–Si-cyclic units were prepared. The new copolymers showed stable and ultra-low dielectric constants below 2.0, tunable glass transition temperature and mechanical performance.

Experimental evaluation of scatter in fracture stress of silicate glass and its thickness dependence

Glass is widely used in various structural application, where a transparent, durable, and stiff material is needed. Although glass is primarily not a load-bearing member in applications, however, even in common usage of glass as windows panes it is exposed to loads, such as wind loads, thermal and other mechanical loads, and may also be exposed to vibratory, impact and blast loading. However, these materials are brittle in nature and cannot withstand thermal loads beyond a certain limit. Moreover, there is a substantial scatter in their fracture stress and the median values of fracture stress is dependent upon the thickness of the specimen used in the tests. In order to study the effect of specimen thickness on fracture stress and its scatter, several experiments have been conducted on different thickness of glass material. Three point bend test was conducted on various glass specimens of 4 mm and 8 mm thickness to ascertain the scatter in the fracture strength of the glass specimen. A lot of scatter in the fracture strength of the glass specimen was observed which is attributed to the presence of micro crack on the surface of the glass specimen. Scatter in fracture stress is higher for 8 mm thickness of glass as compared to 4 mm glass specimen. It was seen that the cumulative experiment probability of fracture strength of glass follows a Weibull model. It was seen that the fracture strength of the glass reduces from 46 MPa to 40 MPa with the increase in thickness from 4 mm to 8 mm respectively indicating the decrease in fracture toughness with increasing thickness.