Window Applications Research Articles

Stable Radicals in Dihydrophenazine Derivatives-Doped Epoxy Resin for High Photothermal Conversion.

Organic radicals exhibit great potential in photothermal applications, however, their innate high reactivity with oxygen renders the preparation of stable organic radicals highly challenging. In this work, a series of co-doped radical polymers ares prepared by doping dihydrophenazine derivatives (DPPs) into the epoxy resin matrix. DPPs can form radical species through the electron transfer process, which are further stabilized by the complex 3D network structure of epoxy resin. Experimental results show that the photothermal conversion efficiency is as high as 79.9%, and the temperature can quickly rise to ≈130°C within 60 s. Due to the excellent visible light transmittance and mechanical properties of co-doped systems, this study further demonstrates their practical applications in energy-saving solar windows and thermoelectric power generation.

Transparent and Colorless Luminescent Solar Concentrators Based on ZnO Quantum Dots for Building-Integrated Photovoltaics.

Scientific interest in luminescent solar concentrators (LSCs) has reemerged mainly due to the application of semiconductor quantum dots (QDs) as highly efficient luminophores. Recently, LSCs have become attractive proposals for Building-Integrated photovoltaics (BIPV) since they could help conventional photovoltaics to improve sunlight harvesting and reduce production costs. However, most of the modern LSCs rely on heavy-metal QDs which are highly toxic and may cause environmental concerns. Additionally, their absorption spectra give them a characteristic color limiting their potential application in BIPV. Herein, we fabricated transparent and colorless LSCs by embedding nontoxic and cost-effective zinc oxide quantum dots (ZnO QDs) in a PMMA polymer matrix (ZnO-LSC), preserving the QD optical properties and PMMA transparency. The synthesized colloidal ZnO QDs have an average size of 5.5 nm, a hexagonal wurtzite crystalline structure, a broad yellow photoluminescent signal under ultraviolet excitation, and are highly visibly transparent at the employed concentrations (>95% in wavelengths above 400 nm). The optical characterization of the fabricated ZnO-LSCs showed a good visible transparency of 80.3% average visible transmission (AVT), with an LSC concentration factor (C) of 1.02. An optimal device (ZnO-LSC-O) could reach a C value of 2.66 with the combination of optical properties of colloidal ZnO QDs and PMMA. Finally, simulations of the performance of silicon solar cells coupled to the fabricated and optimal LSCs under standard AM 1.5G illumination were performed employing the software COMSOL Multiphysics. The fabricated ZnO-LSC achieved a simulated maximum power conversion efficiency (PCE) of 3.80%, while the optimal ZnO-LSC-O reached 5.45%. Also, the ZnO-LSC generated a maximum power of 15.02 mW and the ZnO-LSC-O generated 40.33 mW, employing the same active area as the simulated solar cell directly illuminated, which generated 14.39 mW. These results indicate that the ZnO QD-based LSCs may be useful as transparent photovoltaic windows for BIPV applications.

Design, fabrication, and physical properties analysis of laminated Low-E coated glass for retrofit window solutions

The ever-growing demand for improved energy efficiency in buildings has stimulated a stream of research focused on innovative retrofit energy solutions. Laminated low emissivity (Low-E) type coated glass components can be used in retrofitting window systems for enhancing energy savings provided by the insulating properties of glass laminates containing these heat-mirror-type coatings. In particular, custom-designed double-silver low-E coatings embedded into the laminate structure (directly facing the polymer interlayers during and after the lamination) are of interest due to being protected from environmental exposure, enabling easy component transportation, storage, and window retrofits. In this study, we provide some details on the design of several reflector-type solar control low-E coatings of high environmental stability and demonstrate the feasibility of their fabrication on 3 mm thick glass substrates, followed by the lamination. We describe the optical properties of laminated structural glass components of potential usefulness for retrofitting window applications in new and existing buildings. Several thin-film coatings of a low-E type are deposited by using the RF magnetron sputtering technique and then subjected to lamination by using transparent epoxy and PVB materials, to be protected by a clear glass cover layer. The optical performance characteristics of these coatings (measured before and after lamination) elucidate the effects these lamination materials and cover glass thickness have on the final optical properties (leading to a slight reduction in the optical transmission in the visible spectral range, by around 8–10 % while retaining low thermal emissivity across the infrared spectral range). The outcomes of this research, if industrialized could contribute significantly to the development of sustainable building components and practices, and to acheiving a reduction in building energy consumption by way of enabling window retrofit operations at potentially reduced costs.

Electropolymerization of D-A-D type butterfly-shaped monomers based on triphenylamine-thiophene consisting of camphor substituted quinoxaline moiety for efficient electrochromism and supercapacitors

Two new butterfly-shaped monomers TTCQF and TTCQH consisting of camphor-substituted quinoxaline units as π-spacers were designed and synthesized, which were further electrochemical polymerized and deposited on ITO substrates for electrochromic energy storage devices. The present cross-linked polymer thin films PTTCQF and PTTCQH displayed prominent color changes with significant optical contrast in both the visible and near-infrared regions under external electrical stimuli. These two polymers showcased superior electrochromic performance, involving high optical contrast, fast switching speed, and good coloration efficiency. Additionally, both polymers demonstrated a high areal specific capacitance (12 mF/cm2 for PTTCQH and 9.97 mF/cm2 for PTTCQF) at a current density of 0.1 mA/cm2. Electrochromic energy storage devices based on these polymers were fabricated, and not only illuminated an LED bulb but also visually indicated the energy storage state, guaranteed their potential for applications in energy-saving smart windows. This work may provide valuable insights into the development of efficient cross-linked electrochromic energy storage polymers.

The Influence of Financial Literacy, Pocket Money and Lifestyle on Student Consumptive Behavior on Online Shopping Platforms

Consumption behavior in the current digitalization era is high because shopping platforms make it easier for everyone to access online shopping through several online shopping platforms. For students, uncontrolled consumptive behavior will burden their finances and cause financial problems to arise in the future. The purpose of this study was to determine (1) the effect of financial literacy on student consumptive behavior on online shopping platforms, (2) the effect of pocket money on student consumptive behavior on online shopping platforms, (3) the effect of lifestyle on student consumptive behavior on online shopping platforms (4 ) the effect of financial literacy, pocket money and lifestyle on student consumptive behavior on online shopping platforms. This study uses descriptive quantitative research with correlational methods using the help of the IBM SPSS Statistics 25 for Windows application program. The population in the study was 136, and in determining the sample using a purposive sampling technique, were 101 respondents in the sample. Data collection for financial literacy used tests for pocket money variables, lifestyle and consumptive behavior using questionnaires. Based on the results of the analysis, it can be concluded that (1) there is an effect of financial literacy on consumptive behavior, (2) there is an effect of pocket money on consumptive behavior, (3) there is an influence of lifestyle on consumptive behavior(4) there is a simultaneous effect of financial literacy, pocket money and lifestyle towards consumptive behavior.

Viologen-functionalized biomass-based furan trimer as a multi-coloring electrochromic material

The ability of electrochromic devices (ECD) to undergo a reversible color change when exposed to different voltage conditions has rendered them suitable for applications in smart mirrors, energy-efficient windows, and multi-color displays. While most of the compounds used for ECD fabrication are inorganic metal oxides, various studies have demonstrated that organic materials can also be promising candidates for ECD applications. Recently, our research group introduced a trifuran oligomer that can undergo reversible colorations at lower voltage ranges. However, the decoloration ability of the compound for a better color transition upon reduction remains a challenge. In this study, we successfully synthesized a viologen-functionalized biomass-based trimer and explored its electrochromic properties. Based on our findings, the novel compound exhibited a red to transmissive yellow to deep blue multi-coloring ability when it undergoes oxidation and reduction by virtue of its electrochromic components. Additionally, the introduction of viologen to the structure of the trifuran moiety enhanced the decoloration capacity of the ECD, therefore rendering the color transitions more visible.

A sustainable utilization approach of waste biomass resources to smart materials for buildings

Resource utilization of solid waste promotes resource conservation, energy transformation and sustainable development. In this study, we developed a synthetic strategy for converting biomass waste, such as waste bamboo powder, into a smart material with thermochromic properties - hydroxypropyl cellulose (HPC). The synthesis process includes extraction of cellulose and modification with hydroxypropyl groups. The maximum extraction efficiency of cellulose from raw bamboo powder was up to 48 % by carefully adjusting the reaction conditions including NaOH concentration, reaction time, and treatment temperature. The maximum yield of modification process was achieved to 1.32 g/g by optimizing alkalization temperature, alkalization time, NaOH concentration, propylene oxide concentration, etherification temperature and etherification time. The samples were characterized by a variety of techniques such as FTIR, 1H NMR, XRD, SEM to validate the micro-structure of the extracted cellulose the HPC materials. Moreover, this study explored the potential application of HPC hydrogel in smart window application, and evaluated its building energy saving efficiency under different climate conditions through computational simulation. The corresponding results showed that the HPC hydrogel smart window could have significant energy saving potential compared to ordinary clear glass window. This novel approach of converting waste resources into high valued thermochromic materials for smart windows, not only reduces waste disposal demand for excessive land-use and energy consumption but also shows a positively contributes to sustainable development, environmental protection, as well as energy conservation.

Revelation of luminescence-thermometry, light generation in first biological window and IR detection capabilities of sodium yttrium fluoride co-doped with Yb3+ and Er3+ ions synthesized by low-cost approach

Microwave-assisted combustion synthesis approach is adopted to prepare sodium yttrium fluoride co-doped with ytterbium and erbium (NaYF4: Er3+/ Yb3+) nanoparticles. PXRD confirms the formation of mixed phase (cubic and hexagonal) of the NaYF4: Er3+/ Yb3+ crystal lattice. It is determined that the cubic phase dominates over the hexagonal phase. Three characteristic emission peaks appearing at 523, 544 and 672 nm are attributed to the transitions 2H11/2, 4S3/2 - 4I15/2 and 4F9/2 - 4I15/2 respectively which is character of Er3+ ions, confirming the potential in first biological window applications. The optimal dopant concentration is found and the asymmetric ratio is calculated. Strong up-conversion emission has been observed in the sample in the yellowish-green area when excited with 980 nm radiation. The life time of the 4S3/2 (green) and 4F9/2 (red) levels are found to be 1.187 and 0.472 ms respectively. The emission occurring in the synthesized sample follows the two-photon process which is confirmed by double log graph of intensity and pump-power. Thermal sensitivity is recorded in the range of 300–540 K. The thermally and non-thermally coupled levels attributed to the transitions (2H11/2 and 4S3/2) to (2H11/2 and 4F9/2) of Er3+ ions which are employed to study the temperature sensing. Higher relative sensitivities in both thermally and non-thermally coupled levels were observed in the samples with their values being 1.33 % K−1 and 1.81 % K−1 correspondingly. The significant thermal sensitivity of the synthesized phosphor materials improves its possibility in optical thermometric applications. Further to study the light-emitting abilities of the prepared phosphor, a phosphor-in-glass structure was fabricated using a borate-based glass system. The photometric parameters such as luminous efficacy of radiation and luminous efficiency were obtained to be 331 lm/Wopt and 48.46 % respectively. The prepared compound exhibits superior IR sensing which is evident upon exposure of the fabricated P-i-G to 980 nm radiation. The performed studies authenticate the capabilities of the cubic phase NYF in optical thermometry, light generation and IR detection abilities.

Comprehensive effect on the development of multifunctional low emissive and transparent conductive amorphous-SIZO/Ag/amorphous-SIZO multilayer structure

Wide band gap oxide semiconductors based on transparent conducting electrodes (TCEs) are promising for the fabrication of a wide range of electronic and optoelectronic devices, which include flat panel displays, photovoltaics, transparent heaters, and smart windows. High optical transmittance in the visible spectral range and low electrical resistivity as obtained by intrinsic and/or extrinsic doping, lead to a high figure of merit (FoM) for oxide based TCEs. Recently, we have used wide band gap amorphous Si–In–Zn–O (SIZO) to realize a relatively new class of TCEs using SIZO/Ag/SIZO multilayer structures, which exhibit high FoM in addition to infrared reflection capability due to the embedded ultrathin Ag metal layer. These multifunctional TCEs are found to be highly useful for low emissive smart window applications, which minimize the outside infrared to coming inside and efficiently reflect inside heat to emit outside. In addition, amorphous OMO based TCEs show excellent mechanical endurance, unlike crystalline ITO based coatings. The optical and low emission characteristics of amorphous SIZO OMO were optimized to transmittance of 93.4 % at 550 nm and 58.6 % at 950 nm.

Optimization of Cr/Sc-based multilayer mirrors for water window soft x-rays.

The development of efficient multilayer mirrors for the water window (a spectral region between absorption edges of carbon and oxygen, from 284 to 543 eV) remains a challenge. As the best candidate, the Cr/Sc multilayer provides maximum theoretical reflectivity of about 60% at near-normal incidence around the Sc L2,3 absorption edge (397 eV). However, the maximum measured peak reflectance published so far just slightly exceeds 20%. We report on a new (to the best of our knowledge) approach to design more efficient Cr/Sc-based multilayer coatings using the process of nitridation of chromium during deposition and adding boron carbide as a third material in the multilayer structure. We discuss our strategy of optimization of the CrN/B4C/Sc multilayer system based on experimental studies. The peak reflectance as high as 32% at 396 eV was measured with this type of coating, which is of main interest for various water window applications such as x-ray microscopy.

Electrospun Materials with High Reflectance and Polarization Contrast for Sensing Applications in the Mid-Infrared Atmospheric Window

Electrospun Materials with High Reflectance and Polarization Contrast for Sensing Applications in the Mid-Infrared Atmospheric Window

A double-layer light shutter consisting of polymer dispersed liquid crystal and azo dye/quantum dot

We have developed a double-layer liquid crystal light shutter and investigated its temperature dependent morphological, electro-optical, and dielectric properties. The optical layers of the shutter are in direct contact, reducing optical losses. The shutter comprises a polymer dispersed liquid crystal film adjacent to an azo dye methyl red and CdSeS/ZnS quantum dot doped cholesteric liquid crystal layer. This novel double-layer light shutter device is switchable between opaque and transparent states at room temperature, and it exhibits low threshold and saturation voltages. Both the threshold (Vth) and saturation (Vsat) voltages are found to decrease with increasing temperature. The electrical characteristics of the shutter, namely the real part of dielectric constant (ε′) and the ac conductivity (σac) also increase with temperature in the low frequency region. Our results show that this double-layer light shutter has interesting potential for simple electro-optical devices and smart window applications.

Absorptive metasurface with optical transparency for broadband RCS reduction

Here, we introduce an optically transparent and flexible metasurface designed for effective absorption within the microwave spectrum. Indium tin oxide (ITO) films with varying square resistances fabricate a metasurface ground layer and a lossy pattern layers. Polydimethylsiloxane (PDMS) with a low refractive index, high transparency, and high flexibility is chosen as the dielectric layer. The proposed structure exhibits a reflection band of less than -10 dB with a fractional bandwidth of 167% in the range of 3.0–33.8 GHz under vertical incident electromagnetic waves. The metasurface designed based on this unit allows for the attainment of a radar cross section (RCS) reduction bandwidth of 8.75–31.1 GHz with a 10 dB reduction and a fractional bandwidth of 112%. The metasurface can maintain a broadband RCS reduction over a range of 45° incidence angles. In addition, due to the flexibility of the structure, we analyzed its RCS reduction capability when non-planar by wrapping the structure around a cylinder. The integration of simulation and testing has demonstrated that the structure exhibits excellent performance in the field of electromagnetic stealth. It has potential practical applications in electromagnetic shielding windows and the windows or domes of airplanes or satellites.

Enhanced durability of thermochromic film using VO2 nanoparticles with hybrid shell

Many progresses have been made for commercial application of adaptive VO2-based thermochromic smart window in the improvement of luminous transmittance (Tlum), phase transition temperature, solar regulation efficiency (ΔTsol), color modification, etc. The main obstacle for reaching this goal is relatively poor environmental durability of VO2. To address this issue, VO2 nanoparticle with hybrid shell (VO2@m-SiOx) was prepared by hydrolysis and polycondensation of the mixture of tetraethyl orthosilicate (TEOS) and Methyltriethoxysilane (MTES) using ammonia as catalyst in this paper. The optimized VO2@m-SiOx nanoparticle-based thermochromic films exhibited an ultra-high durability. The ΔTsol of thermochromic film in this study kept 44 % (from 19.0 % to 8.39 %) after 30 days in hyperthermal and humid environments, while the corresponding performance of film using uncoated VO2 nanoparticle disappeared completely after 2 days. This work provided a direct and effective way for improvement of stability of VO2 nanoparticle.

2D ordered porous VO2-based composite film with enhanced thermochromism performance and high stability for smart windows

Thermochromic vanadium dioxide (VO2) can autonomously adjust near-infrared light transmittance in response to the external temperature changes, offering a significant reduction in building energy consumption when applied it in smart window. However, it is a big challenge for simultaneous optimization of visible light transmittance, solar modulation ability, and stability in VO2. To address such a big challenge, this study successfully prepared a 2D ordered porous VO2@Zn3V3O8 composite film. The as-obtained film exhibits exceptional optical performance with a visible light transmittance (Tlum) of 62.75 % and the solar modulation ability (ΔTsol) of 10.62 %, based on the anti-reflective effects of porous structure and the localized surface plasma resonance (LSPR) absorption of independently distributed VO2 nanoparticles. In addition, the composite structural film showcases excellent environmental durability that 80 % of ΔTsol could be retained after 30 days aging under the conditions of 50 % humidity and 100 °C. This work propels the practical application of VO2 smart windows and offers valuable insights for the design of composite structures.

Influence and mechanism of titanium doping on the electrochromic performance of nickel oxide nanofilm

This research investigates the preparation and electrochromic performance of titanium-doped nickel oxide nanofilms. Through chemical bath deposition, nickel oxide doped with various ratios of titanium (NiO) films was successfully synthesized. The study extensively analyzes the structural features and properties of these films using such characterization techniques as X-ray diffraction, transmission electron microscopy, and X-ray photoelectron spectroscopy, among others. The experimental findings highlight that moderate titanium doping (0.3%) notably enhances the porous structure and crystalline properties of NiO films, leading to improved optical modulation (88%), coloring efficiency (CE up to 42.6 cm2/C), and cycle stability (maintaining 61% optical modulation after 500 cycles). However, excessive titanium doping tends to diminish the electrochromic response time. These results underscore the significant impact of titanium doping on the electrochromic performance of NiO films, providing essential insights for their potential applications in smart windows, displays, and related fields.

군용 무인기 비행안전 신뢰성 향상을 위한 점검창 적용 방안 및 영향성 분석 연구

군용 무인기 비행안전 신뢰성 향상을 위한 점검창 적용 방안 및 영향성 분석 연구

Project Scheduling of the Garment Business Using CPM-Crashing based on the POM-QM Application for Windows

Project Scheduling of the Garment Business Using CPM-Crashing based on the POM-QM Application for Windows

Thiol-acrylate based polymer wall-stabilized cholesteric liquid crystal enables flexible bistable states light shutter

Bistable-states mode light shutter boost the applications in smart windows or transparent displays due to the significant energy efficiency. In this study, polymer wall-stabilized cholesteric liquid crystals (PWSCLC) with regular microstructures and outstanding electric field frequency-controlled bistability were prepared using non-liquid crystalline thiol-acrylate monomers system and polymerization under a photomask. The addition and proportion of the thiol monomer played an essential role in the morphology structures of the polymer network. Thanks to the effectively modulation of polymerization speed, periodic regular polymer wall morphology was obtained, which improved the transmittance and the long-term stability. Under a suitable voltage, repeatedly reversible switch between transparent and scattering states was successfully realized via frequency regulation, and both states remained stable for more than 10 days after removing electric field. Remarkably, the mechanical strength of the PSWCLC film was significantly improved due to the relatively high polymer concentration, proving feasibility for the flexible applications and large-scale preparation.

Experimental and Computational Study Toward Identifying Active Sites of Supported SnOx Nanoparticles for Electrochemical CO2 Reduction Using Machine-Learned Interatomic Potentials.

SnOx has received great attention as an electrocatalyst for CO2 reduction reaction (CO2RR), however; it still suffers from low activity. Moreover, the atomic-level SnOx structure and the nature of the active sites are still ambiguous due to the dynamism of surface structure and difficulty in structure characterization under electrochemical conditions. Herein, CO2RR performance is enhanced by supporting SnO2 nanoparticles on two common supports, vulcan carbon and TiO2. Then, electrolysis of CO2 at various temperatures in a neutral electrolyte reveals that the application window for this catalyst is between 12 and 30°C. Furthermore, this study introduces a machine learning interatomic potential method for the atomistic simulation to investigate SnO2 reduction and establish a correlation between SnOx structures and their CO2RR performance. In addition, selectivity is analyzed computationally with density functional theory simulations to identify the key differences between the binding energies of *H and *CO2 -, where both are correlated with the presence of oxygen on the nanoparticle surface. This study offers in-depth insights into the rational design and application of SnOx-based electrocatalysts for CO2RR.