Visible Light Transparency Research Articles

Nanocrystalline Lanthanum Oxide Layers on Tubes Synthesized Using the Metalorganic Chemical Vapor Deposition Technique

Lanthanum oxide (La2O3) layers are widely used in electronics, optics, and optoelectronics due to their properties. Lanthanum oxide is also used as a dopant, modifying and improving the properties of other materials in the form of layers, as well as having a large volume. In this work, lanthanum oxide layers were obtained using MOCVD (Metalorganic Chemical Vapor Deposition) on the inner walls of tubular substrates at 600–750 °C. The basic reactant was La(tmhd)3 (tris(2,2,6,6-tetramethyl-3,5-heptanedionato)lanthanum(III)). The evaporation temperature of La(tmhd)3 amounted to 170–200 °C. Pure argon (99.9999%) and air were used as the carrier gases. The air was also intended to remove the carbon from the synthesized layers. Tubes of quartz glass were used as the substrates. La2O3 layers were found to be growing on their inner surfaces. The value of the extended Grx/Rex2 criterion, where Gr—Grashof’s number, Re—Reynolds’ number, x—the distance from the gas inflow point, was below 0.01. The microstructure of the deposited layers of lanthanum oxide was investigated using an electron scanning microscope (SEM). Their chemical composition was analyzed via energy-dispersive X-ray (EDS) analysis. Their phase composition was tested via X-ray diffraction. The transmittance of the layers of lanthanum oxide was determined with the use of UV-Vis spectroscopy. The obtained layers of lanthanum oxide were characterized by a nanocrystalline microstructure and stable cubic structure. They also exhibited good transparency in both ultraviolet (UV) and visible (Vis) light.

Color/Transparent Bi‐Customizable Solar Antifogging Nanofilms

AbstractAlmost all reported solar anti‐/defogging surfaces are black and opaque. However, aesthetics and transparency are preferred to enhance security, privacy, and visual experience without sacrificing antifogging in some practical scenarios, such as automotive windshields, architectural glass facades, and sports goggles. Herein, a color and transparency bi‐customizable solar antifogging heterostructure nanofilms is reported, which only consists of a Ti–TiOx layer for partial visible light transmission and a narrow bandgap Ti2O3 layer for broadband sunlight absorption. By precisely controlling each monolayer thickness, various vibrant structural colors (covering yellow/green/purple/blue) through interference effects, along with tunable visible light transparency (from 0% to 30%), and broadband solar absorption (up to 90%) are obtained, providing personalized options for various applications. Simultaneously, the nanofilms exhibit remarkable photothermal performance (110.3 °C under 1 kW m−2 irradiation) compared to blank samples, demonstrating sustained and superior defogging (3.5‐fold improvement) and antifogging capabilities, even in extremely cold (–20 °C) or high temperature and high humidity (50 °C, 100%) conditions. Importantly, the nanofilms are just 174 nm thick, and can be easily upgraded and scalable fabricated by sputtering on various rigid, flexible and portable substrates, such as glass, metals, textiles, plastics, enabling a wide range of direct applications.

Effect of Chlorine Inclusion in Wide Band Gap FAPbBr3 Perovskites

AbstractWide bandgap perovskites have recently gained attention owing to their physical properties, versatility, and potential in various optoelectronic devices including LEDs, detectors, and building‐integrated photovoltaics (BIPV). However, BIPV materials must meet conflicting requirements, necessitating high performance, high transparency in the visible spectrum and color neutrality. This study investigates the controlled addition of chlorine in FAPb(Br1‐xClx)3 perovskites to achieve band gaps exceeding 2.4 eV. Increasing chlorine content from xCl = 0.00 to xCl = 0.25 widens the band gap from 2.37 to 2.52 eV, effectively improving the visible light transparency. Advanced characterization techniques including X‐ray diffraction, synchrotron radiation photoelectron spectroscopy, photoluminescence imaging, and fast transient absorption spectroscopy, complemented by density functional theory, reveal insights into absorption properties, electronic structure, and ultrafast recombination dynamics as a function of the thin film chemical composition. Furthermore, this study evaluates energetic disorder, carrier recombination rates, and non‐radiative losses for different compositions by extracting quantitative parameters such as Urbach energy and quasi‐Fermi level splitting, offering novel insights and guidelines for the design and optimization of emerging photovoltaic (PV) materials. Optimal PV performance metrics are achieved with a wide bandgap bromine perovskite containing 14% chlorine, striking a balance between morphology, transparency, and voltage losses.

A multi-function glass shield for neutrons and gamma rays of boron- and bismuth-reinforced silicate glass

A successful attempt to produce a multi-function glass shield for attenuating neutrons and gamma rays by reinforcing a silicate glass network with boron and bismuth has been accomplished. A composition of 20SiO2-80Na2O (BSiBi0) was proposed to be used as a host glass network and prepared using the melt/annealing techniques. The low concentration of SiO2 in BSiBi0 was not sufficient to form a stable glass network. Then, the proposed BSiBi0 was modified with 10, 20, 30, and 40 mol% of each of B2O3 and Bi2O3 (BSiBi1, BSiBi2, BSiBi3, and BSiBi4) simultaneously. The structural effects of adding B3+ and Bi3+ were studied through X-ray diffraction, density, and FTIR, which all showed enhancement of glass forming ability, a former role of Bi3+ ions, and crowded the glass network by BO4 units. The derived structural parameters -\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document} molar volume, mean silicon – silicon separation, mean boron – boron separation, oxygen packing density, packing density, and number of bridging/non-bridging oxygen -\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document} were extensively discussed to explore the impact of B3+ and Bi3+ on the formed network. The richness of the proposed host glass network by B3+ and Bi3+ enhanced its thermal stability. The obtained elastic properties by ultrasonic measurements reflect the increase of the glass rigidity with increasing concentrations of B3+ and Bi3+ ions. The obtained glasses have high visible light transparency and almost complete UV absorption. The measured shielding parameters against two types of neutron energies (total slow and slow) and a wide range of gamma rays’ energies showed a significant improvement in the shielding efficiency of the considered glasses. The total slow neutrons, slow neutrons, and gamma rays’ attenuation abilities were improved by 22.9, 135.5, and 73.8 -\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$-$$\\end{document} 199.5%. High thermal stability, elasticity, visible light transparency, and neutrons and gamma rays’ attenuation performance features give the produced glasses, especially BSiBi4 glass, preference as shielding materials in nuclear fields.

PI-SiO2 aerogel as a versatile high transparent material for photothermal cooperative management

Effectively insulating against excessive heat generated by sunlight while also avoiding harmful ultraviolet (UV) and maintaining suitable levels of visible light transparency is vital for minimizing energy consumption and optimizing sunlight utilization. To address the challenge of photothermal collaborative management, the PI consisted of high fluorinated dianhydride and aliphatic diamine was used to effectively improve the performance of SiO2 aerogels. The resulting PI-SiO2 aerogels retain the characteristics of SiO2 aerogels, such as low density, high transparency between 82∼89 %, and excellent thermal insulation properties with an ultralow thermal conductivity range from 0.023 W/(m.K) to 0.028 W/(m.K). Meanwhile, the coarsened skeleton of aerogels can withstand the extreme temperature difference between −196 ℃ and 200 ℃ without brittle fracture and yellowing. In addition, PI-SiO2 aerogels exhibit the capability to absorb a significant proportion of UV light within the 200–400 nm, offering distinct advantages in transparent thermal insulation materials. The multifunctional PI-SiO2 aerogels can be used as candidate materials in the fields of architecture, automobile, electronics, solar energy and aerospace.

Smart Window with Reversible and Instantaneous Photoluminescence based on Microsphere Structure.

A smart window that dynamically regulates light transmittance is crucial for modern life end-users and promising for on-demand optical devices. The advent of three-dimensional (3D) photonic crystal microspheres has enriched the functions of a smart window. However, the smart window formed by polymer microspheres encounters poor mechanical strength and microstructural defects. Herein, to solve this limitation, we report the microsphere-based smart window composed of tightly packed cross-linked polymer microspheres (as a precursor) containing organic photochromic dyes, followed by compression under a high elastic state. When excited under an ultraviolet supply, our smart window showed a rapid and reversible fluorescent photoluminescence without fatigue (50 cycles). Moreover, the bulk devices with a microsphere cross-linked network structure enable excellent mechanical strength (hardness reached 0.158 GPa) and visible-light transparency. Interestingly, a QR code can be recognized under visible light exposure but not under ultraviolet light exposure because of photoluminescence of the smart window. Our method generally provided a paradigm for various amorphous polymers, which can be regarded as a simple and effective approach to build a versatile strategy to introduce an ideal marketplace with economic and community benefits.

Tolerance of Corundum‐Structured Tin‐Doped Indium Oxide Thin Films to Gamma‐ray Irradiation

Corundum‐structured Sn‐doped indium oxide (rh‐ITO) is investigated as a novel transparent conductive oxide. Herein, its gamma‐ray tolerance up to a total dose of 77 kGy is examined for potential applications in harsh environments, such as space. The investigations are conducted on rh‐ITO with Sn concentrations of 0 and 5 at%. X‐ray diffraction 2θ‐ω scan analysis reveals that no phase separation occurs due to gamma‐ray irradiation. The carrier concentration in undoped rh‐In2O3 increases after irradiation, indicating that the gamma rays displace the oxygen atoms and form oxygen defects that generate donors. The high visible light transparency of rh‐In2O3 and rh‐ITO is maintained after irradiation. This study demonstrates the high stability of rh‐ITO to gamma‐ray irradiation until 77 kGy dose. This work contributes to the application of rh‐ITO as an electrode in high‐radiation environments.

Macrocyclic Supramolecular Glass: New Type of Supramolecular Transparent Materials.

Transparent materials are widely used in industries, everyday life, and scientific activities. The development of new, lightweight, and durable artificial transparent materials is a challenge in synthetic chemistry. In this study, a supramolecular approach is conceived to construct transparent glass. Cyclodextrins are selected as the building blocks for the fabrication of supramolecular glass via noncovalent polymerization. The newly formed glass displays several attractive advantages, including good thermal processability, high mechanical strength and dielectric constant, excellent visible light transparency, and good adhesion performance. Importantly, the structural characteristics of long-range disorder and short-range order are observed in cyclodextrin glass. Here a new strategy is presented for the preparation and functionalization of low-molecular-weight transparent materials.

Evaluation of optical and self-healing properties of Titania/ionic liquid/poly(butyl methacrylate) hybrid material based on thermally reversible Diels–Alder chemistry

ABSTRACT In this study, we report the development of a hybrid polymer material comprising poly(butyl methacrylate) and titania, which exhibits the three key elements of visible-light transparency, UV shielding, and self-healing. Nanodispersion of titania in the polymers was achieved using the sol – gel method using titanium propoxide as the raw material. Furthermore, by adding tetrabutylphosphonium chloride, an ionic liquid, we suppressed visible light absorption due to charge transfer between poly(butyl methacrylate) and titania, resulting in enhanced visible light transmittance. An approach involving crosslinking points comprising Diels – Alder functional groups was used to heal scratches in the hybrid material at 75°C for 30 min. Dynamic viscoelastic measurements and microscopic observations were conducted to investigate the self-healing mechanism. These findings suggested that this phenomenon occurred through the fluidization of the polymer matrix and the recombination reaction of the crosslinking points, which comprise Diels – Alder and titania. The development of intelligent materials with combined transparency, UV protection, and self-healing capabilities provides potential avenues for future research to enhance and broaden their versatile characteristics for widespread applications.

First principles investigation on CaxLa1-xB6 as the solar radiation shielding material for energy-efficient windows

To improve the visible transparency and the absorption capacity of near-infrared light of LaB6, the electronic structure and optical properties of the substitution of La with Ca were studied through first principles calculations. The results show that Ca0.125La0.875B6 exhibits satisfactory solar radiation shielding performance with high transparency of visible light for energy-efficient windows. However, Ca0.25La0.75B6 exhibits weaker absorption properties in both visible and near-infrared light. This work offers theoretical guidance for the application and design of the solar radiation shielding material for energy-efficient windows.

Simultaneous enhancements of UV-shielding properties and photostability of polyvinyl butyral by incorporation of MWCNTs

Polymer nanocomposites with proper reinforcement can simultaneously enhance both the UV-shielding and optical properties. Such composite materials are being investigated for many commercial applications, including automotive, window screens etc. However, the inherent challenge is maintaining transparency while using reinforcement to get better optical properties and UV resistance. In this study, Multiwall Carbon Nanotubes (MWCNTs) were reinforced for a range of content (0.5, 1.0, 1.5 and 2.0 wt%) in Polyvinyl Butyral (PVB) matrix to synthesize nanocomposite films for UV-shielding purposes. UV-shielding properties are enhanced as compared to PVB for all compositions. We were adding 0.5 wt% MWCNTs to PVB effectively improved UV wavelength blocking and slightly decreased visible light transparency. UV studies were performed in the 190–1100 nm wavelength range and the values of the absorption edge, direct and indirect bandgap energies and Urbach energy were evaluated. When 0.5 wt% MWCNTs were reinforced into the PVB, the direct and indirect bandgaps changed significantly from 4.50 to 4.91 eV–3.01 eV and 4.06 eV respectively, while the Urbach energy increased from 0.73 eV to 1.16 eV. These results show that the UV shielding and photostability of PVB nanocomposite films are significantly changed with the low dispersion of MWCNTs.

Asymmetric nanofiber photothermal interactive electronic skin with triboelectric autonomous thermal perceptivity

Thermal-perceptive electronic skins (e-skin) represent an important functional interface in wearables and soft robots. Realizing an all-in-one structured nanofiber interactive e-skin with autonomous thermal perceptivity remains challenging. We demonstrated a polyurethane/(polyvinyl pyrrolidone/MXene) (PPM) bilayer nanofiber film with asymmetric structure compactness by continuous and controllable electrospinning, that achieves asymmetric optical transmittance (visible light transparency of 20∼97%, infrared transparency of 5.5∼34.1%) and photothermal actuation response, with a response rate of 0.8 mm−1 s−1 and bending curvature of 2.2 cm−1, as well as additional excellent triboelectric outputs of ∼320 V and ∼5.4 µA. We proposed a “contact-actuation-perception” strategy for instantaneous object temperature sensing based on the PPM, which can actuate under photothermal stimulation to change its contact area with the target objects at different temperatures, producing temperature-dependent distinguishable triboelectric signals for autonomous thermal perception, with sensitivity up to ∼99.6%. This work could inspire a facile strategy to realize asymmetric features in fiber materials, in which the asymmetric optical-thermal-mechanical-electrical coupling mechanism for active perception is expected to promote the development of autonomous interactive e-skins.

Metal oxide-dispersed PDMS nanocomposite films with enhanced heat-shielding ability and optical transparency

Coatings that transmit visible light and shield near-infrared (NIR) rays of sunlight have potential applications in smart windows, thermal camouflage, and heat shielding encapsulations. Here, we report metal oxide-dispersed polymer nanocomposites as potential coating materials that possess a combination of NIR reflection and visible light transmission. Film coatings (∼600 μm) comprising nanocrystalline zinc oxide (ZnO), titanium dioxide (TiO2), and cupric oxide (CuO) in the range of 0–2 wt% in polydimethylsiloxane (PDMS) matrix are fabricated. At optimal compositions, these coatings provided up to 52 % reduction in the interior air temperature, measured at distances ∼3 cm beneath the surface, while, at the same time, retaining up to 70 % of visible light transparency. The NIR reflection may be attributed to a combination of the band gap of the pigment material and the difference between the refractive indices of the pigments and the polymer matrix. We present a design map that highlights different regimes of heat-shielding and light transmission space for PDMS nanocomposite films. The performance, when compared with existing reports, suggests that films fabricated in this work outperform previously reported polymeric coatings in providing a combination of heat shielding and optical transparency.

Transparent ultrahigh-molecular-weight polyethylene/MXene films with efficient UV-absorption for thermal management

The rational use and conversion of energy are the primary means for achieving the goal of carbon neutrality. MXenes can be used for photothermal conversion, but their opaque appearance limits wider applications. Herein, we successfully develop visible-light transparent and UV-absorbing polymer composite film by solution blending the MXene with polyethylene and then vacuum pressing. The resulting film could be quickly heated to 65 °C under 400 mW cm−2 light irradiation and maintained over 85% visible-light transmittance as well as low haze (<12%). The findings of the indoor heat insulation test demonstrate that the temperature of the glass house model covered by this film was 6-7 °C lower than that of the uncovered model, revealing the potential of transparent film in energy-saving applications. In order to mimic the energy-saving condition of the building in various climates, a typical building model with this film as the outer layer of the window was created using the EnergyPlus building energy consumption software. According to predictions, they could reduce yearly refrigeration energy used by 31-61 MJ m−2, and 3%-12% of the total energy used for refrigeration in such structures. This work imply that the film has wide potential for use as transparent devices in energy-related applications.

Biomimetic Nanoporous Transparent Universal Fire-Resistant Coatings.

The inherent flammability of most polymeric materials poses a significant fire hazard, leading to substantial property damage and loss of life. A universal flame-retardant protective coating is considered as a promising strategy to mitigate such risks; however, simultaneously achieving high transparency of the coatings remains a great challenge. Here, inspired by the moth eye effect, we designed a nanoporous structure into a protective coating that leverages a hydrophilic-hydrophobic interactive assembly facilitated by phosphoric acid protonated amino siloxane. The coating demonstrates robust adhesion to a diverse range of substrates, including but not limited to fabrics, foams, paper, and wood. As expected, its moth-eye-inspired nanoporous structure conferred a high visible light transparency of >97% and water vapor transmittance of 96%. The synergistic effect among phosphorus (P), nitrogen (N), and silicon (Si) largely enhanced the char-forming ability and restricted the decomposition of the coated substrates, which successfully endowed the coating with high fire-fighting performance. More importantly, for both flexible and rigid substrates, the coated samples all possessed great mechanical properties. This work provides a new insight for the design of protective coatings, particularly focusing on achieving high transparency.

Harnessing the Synergetic Effects of Ag, Mn Dopants in Eco-Friendly Ultraviolet Selective Quantum Dots for Luminescent Solar Concentrators.

Quantum dots (QDs) are promising building blocks for luminescent solar concentrators (LSCs), yet most QD-based LSCs suffer from toxic metal composition and color tinting. UV-selective harvesting QDs can enable visible transparency, but their development is restricted by large reabsorption losses and low photoluminescence quantum yield (PLQY). The developed here Ag, Mn: ZnInS2/ZnS QDs show a high PLQY of 53% due to the passivating effect of ZnS shell. These QDs selectively absorb UV light and emit orange-red light with a large Stokes shift of 180nm. A LSC of 5×5×0.2cm3, fabricated using a poly(lauryl methacrylate) (PLMA) as a matrix, maintains 87% of integrated PL after 7h of UV exposure. The QD-PLMA achieved 90.7% average visible transparency (AVT) and a color rendering index (CRI) of 95.8, which is close to plain PLMA (AVT=90.8%; CRI=99.5), yielding excellent visible light transparency. Incorporating Si-PVs at LSC edges, the Ag, Mn: ZIS/ZnS QD-LSC achieved an optical efficiency of 1.42%, ranking competitively among high-performing UV-harvesting LSCs.

Coconut husk-lignin derived carbon dots incorporated carrageenan based functional film for intelligent food packaging

Carbon dots (CDs) derived from sustainable natural feed-stocks like lignin have gained wide acceptance by virtue of their renewability and promising potential in intelligent sensing applications. The precursor lignin is isolated from agro-biomass waste, coconut husk through sodium hydroxide based extraction process. CDs are synthesised from amine functionalized lignin through solvothermal process and integrated into carrageenan biopolymer matrix (1, 2 and 3 wt%). The composite film with 2 wt% CDs (CARR2CD) showed optimum fluorescent emission intensity, excellent pH dependent fluorescent color change in the food pH range, reasonable tensile strength (46.50 ± 1.32 MPa) and 27 % increase in elongation at break. CDs imparted UV-light blocking properties (70 % UV-light) and enhanced hydrophobicity of the carrageenan matrix. CARR2CD film showed 84 % visible light transparency, 79 % reduction in oxygen transmittance rate (OTR), 81 % reduction in CO2 gas permeability and excellent antioxidant and antibacterial properties (against E. coli and S. aureus). As a practical application, the developed responsive packaging material is used to track pH change associated with milk spoilage via noticeable color change in fluorescent emission of the composite film. Thus, the developed responsive composite film paves a way for use as green and sustainable transparent intelligent food packaging material.

Selectively self-recyclable, highly transparent and fire-safe polycarbonate plastic enabled by thermally responsive phosphonium-phosphate.

Both the circular economy and fire-safety of polymer plastics have become a global consensus. Herein, an integrated strategy for selectively self-recyclable, highly-transparent and fire-safe polycarbonate plastic is proposed by thermally responsive phosphonium-phosphate (DP). During its service life, DP, as a flame-retardant with good compatibility, enables polycarbonate plastic with high transparency in visible light, excellent self-extinguishing and high fire-safety. After consumption, DP, as a catalyst, triggers the selective self-recycling of DP-containing polycarbonate in mixed plastics and even in same-kind polycarbonate plastics without an external catalyst. Importantly, the oxygen-consuming mechanism at high temperature in fire accidents (>350 °C) and the double hydrogen bond catalysis mechanism at a lower temperature (180 °C) of DP are key to the life cycle management of polycarbonate from use-stage to post-consumption. This work inspires a new solution to plastic pollution by designing sustainable plastics that satisfy both service-stage and end-of-life criteria, striving towards a zero-waste circular economy.

A 1064 nm laser adaptive limiter with visible light transparency based on one dimensional photonic crystals of LiNbO3 defects.

Herein, we present the investigation of the visible light transparency and optical limiting characteristics of one dimensional photonic crystals with LiNbO3 defects fabricated by the sputtering technique. Transmission spectroscopy measurements reveal a broad photonic band gap with a 1064 nm defect mode and high transmittance within the visible range. The optical energy limiting performance in the photonic crystal can be attributed to the strong confinement of the optical field surrounding the LiNbO3 defect layer. The low energy 1064 nm laser demonstrates a transmittance of 82.15%. Notably, the optical limiting threshold is lower at 62.03 mJ cm-2 in comparison with conventional optical limiting materials. Additionally, the optical limiter achieves a transmittance of 68.57% within the visible light band.

Sprayed water-based lignin colloidal nanoparticle-cellulose nanofibril hybrid films with UV-blocking ability.

In the context of global climate change, the demand for new functional materials that are sustainable and environmentally friendly is rapidly increasing. Cellulose and lignin are the two most abundant raw materials in nature, and are ideal components for functional materials. The hydrophilic interface and easy film-forming properties of cellulose nanofibrils make them excellent candidates for natural biopolymer templates and network structures. Lignin is a natural UV-shielding material, as it contains a large number of phenolic groups. In this work, we have applied two routes for spray deposition of hybrid films with different laminar structures using surface-charged cellulose nanofibrils and water-based colloidal lignin particles. As the first route, we prepare stacked colloidal lignin particles and cellulose nanofibrils hybrid film through a layer-by-layer deposition. As the second route, we spray-deposite premixed colloidal lignin particles and cellulose nanofibrils dispersion to prepare a mixed hybrid film. We find that cellulose nanofibrils act as a directing agent to dominate the arrangement of the colloidal lignin particles in a mixed system. Additionally, cellulose nanofibrils eliminate the agglomerations and thus increase the visible light transparency while retaining the UV shielding ability. Our research on these colloidal lignin and cellulose nanofibril hybrid films provides a fundamental understanding of using colloidal lignin nanoparticles as functional material on porous cellulose-based materials, for example on fabrics.