High Visible Light Transparency Research Articles

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.

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.

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.

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.

Flexible and Transparent Bagasse Aerogels for Thermal Regulation Glazing

The preparation of functional composite aerogels for building envelopes, especially for building glazing as the key climate moderator, has been widely investigated to improve the sustainability of buildings. Unfortunately, the prohibitive costs, mechanical brittleness, and optical opacity limit the current development and application of composite aerogels. Herein, using the controllable extraction of cellulose from bagasse, a low-cost (less than $3 per square foot), flexible (>15% elastic deformation under 0.02 MPa) bagasse aerogel film with high visible-light transparency (>80% transmittance of visible light) and superinsulation (0.0158 W m–1 K–1) was developed. These properties were achieved by constructing a uniform three-dimensional network structure using elastic polysiloxane and a mixture of cellulose nanofibers and cellulose nanocrystals in an equal proportion. This cellulosic aerogel film would have the latent potential of application in highly glazed modern buildings to reduce the energy loss from windows.

Visible-Light Transparent, Ultrastretchable, and Self-Healable Semicrystalline Fluorinated Ionogels for Underwater Strain Sensing

The development of ultrastretchable ionogels with a combination of high transparency and unique waterproofness is central to the development of emerging skin-inspired sensors. In this study, an ultrastretchable semicrystalline fluorinated ionogel (SFIG) with visible-light transparency and underwater stability is prepared through one-pot copolymerization of acrylic acid and fluorinated acrylate monomers in a mixed solution of poly(ethylene oxide) (PEO) and fluorinated ionic liquids. Benefiting from the formation of the PEO-chain semicrystalline microstructures and the abundant noncovalent interactions (reversible hydrogen bonds and ion-dipole interactions) in an ionogel, SFIG is rendered with room-temperature stable cross-linking structures, providing high mechanical elasticity as well as high chain segment dynamics for self-healing and efficient energy absorption during the deformation. The resultant SFIG exhibits excellent stretchability (>2500%), improved mechanical toughness (7.4 MJ m-3), and room-temperature self-healability. Due to the high compatibility and abundance of hydrophobic fluorinated moieties in the ionogel, the SFIG demonstrates high visible-light transparency (>97%) and excellent waterproofness. Due to these unique advantages, the as-prepared SFIG is capable of working as an ultrastretchable ionic conductor in capacitive-type strain sensors, demonstrating excellent underwater strain-sensing performances with high sensitivity, large detecting range, and exceptional durability. This work might provide a straightforward and efficient method for obtaining waterproof ionogel elastomers for application in next-generation underwater sensors and communications.

RuO2-decorated CsxWO3 composite nanorods as transparent photothermal negative electrode material for enhancing supercapacitor performance in acid electrolyte

With the development of wearable and portable electronics, flexible transparent photothermal supercapacitors which improve the performance via the utilization of sunlight have received increasing attention. The high performance electrode materials, particularly those for negative electrodes in acid electrolytes, are needed. Herein, we developed a novel flexible transparent photothermal supercapacitor using RuO2-decorated CsxWO3 nanorods as the negative electrode material for acid electrolytes. It was demonstrated that the resulting electrodes possessed good pseudocapacitive performance in the potential window of −0.5–0.0 V in 1 M H2SO4 and the appropriate decoration of RuO2 on CsxWO3 nanorods could raise the pseudocapacitance effectively. Also, the fabricated all-solid-state supercapacitor was shown to possess high visible light transparency, flexibility, capacitive performance and stability. Its electrochemical performances could be remarkably enhanced by simulated sunlight illumination because the photothermal conversion-induced temperature increase might reduce the electrolyte and charge-transfer resistances effectively. Further kinetic analysis revealed that the enhanced capacitance was contributed by both the diffusion-limited and surface-limited processes. Accordingly, the strategy to improve the capacitive performance of CsxWO3 nanorods by RuO2 decoration was successful and made the resulting composite have great potential as the negative electrode material for transparent photothermal supercapacitors.

In situ facile one-step solvothermal synthesizing hexagonal ammonium tungsten bronze (NH4)0.33WO3 to tap NIR light absorption ability by controlling crystallinity

Tungsten bronze (TB) has potentially high visible light transparency and excellent near-infrared (NIR) shielding ability. To fully dig out the concealed optical properties of TB with specific chemical components, in this work, hexagonal ammonium tungsten bronze (h-ATB) (NH4)0.33WO3 was fabricated by a one-step solvothermal reaction. Through X-ray diffractometer (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and ultraviolet–visible–near infrared (UV–vis–NIR) spectroscopy to characterize h-ATB, which unraveled that controlling crystallinity could adjust the optical property of h-ATB. In particular, when the crystallinity of the h-ATB is over 95%, it exhibits the attractive NIR light shielding capability, which is in line with the predicted optical property via the first principle calculation based on density functional theory (DFT). Given the result, this work can provide a feasible research idea to explore the hidden optical properties of TB.

NIR band-pass filters for CMOS image sensors constructed with NIR absorbing dyes and plasmonic nanoparticles.

Two NIR band-pass filters for CMOS image sensors are developed by incorporating NIR absorption dye and silver nanodisks simultaneously in a transparent polymer, one of which blocks the NIR near the wavelength of 750 nm and the other near 950 nm. They offer low NIR transmittance while maintaining high visible light transparency even at a thin film thickness of 500 nm. By superimposing the proposed NIR band-pass filters, an NIR cutoff filter with a thickness of 1 µm is formed that shields the NIR at wavelengths longer than 680 nm while remaining transparent in the visible range.

Realizing translucency in aluminosilicate glass at ultralow temperature via cold sintering process

Glass with high visible-light transparency is widely considered as the most important optical material, which typically requires a processing temperature higher than 1000 °C. Here, we report a translucent aluminosilicate glass that can be prepared by cold sintering process (CSP) at merely 300 °C. After eliminating structural pores in hexagonal faujasite (EMT)-type zeolite by heat treatment, the obtained highly active nanoparticles are consolidated to have nearly full density by adding NaOH solution as liquid aids. However, direct densification of EMT powder cannot remove the structural pores of zeolite completely, leading to an opaque compact after the CSP. It is proved that the chemical reaction between the NaOH- and zeolite-derived powders is highly beneficial to dissolution-precipitation process during sintering, leading to the ultra-low activation energy of 27.13 kJ/mol. Although the addition of 5 M NaOH solution greatly promotes the densification via the reaction with aluminosilicate powder, lower or higher concentration of solvent can deteriorate the transmittance of glass. Additionally, the CSP-prepared glass exhibits a Vickers hardness of 4.3 GPa, reaching 60% of the reported value for spark plasma sintering (SPS)-prepared sample.

Pressure Engineering Promising Transparent Oxides with Large Conductivity Enhancement and Strong Thermal Stability.

Transparent conducting oxides (TCO) with high electrical conductivity and high visible light transparency are desired for a wide range of high-impact engineering. Yet, usually, a compromise must be made between conductivity and transparency, limiting the practical application of a TCO to the next level. Furthermore, TCO performance is highly sensitive to composition, so conventional synthesis methods, such as chemical doping, cannot unravel the mysteries of the quantitative structure-performance relationship. Thus, improving the fundamental understanding or creating materials-by-design has limited success. Here, a strategy is proposed to modulate the lattice and electronic and optical properties precisely by applying pressure on a TCO. Strikingly, after compression-decompression treatment on the indium titanium oxides (ITiO), a highly transparent and metastable phase with two orders of magnitude enhancement in conductivity is synthesized from an irreversible phase transition. Moreover, this phase possesses previously unattainable filter efficiency on hazardous blue light up to 600°C, providing potential for healthcare-related applications with strong thermal stability up to 200°C. These results demonstrate that pressure engineering is a clean and effective tool for tailoring functional materials that are not achievable by other means, providing an exciting alternative property-tuning dimension in materials science.

Semitransparent polymer solar cell/triboelectric nanogenerator hybrid systems: Synergistic solar and raindrop energy conversion for window-integrated applications

Development of photovoltaic (PV)-derived hybrid power systems can overcome the weather-dependent electricity production and increase the amount of dispatchable renewable energy generation. Herein, monolithic hybrid devices are developed via rational integration of high-performance semitransparent polymer solar cells (ST-PSCs) and liquid−solid triboelectric nanogenerators (TENGs). High-performance PSCs with efficiencies of 17.4% for rigid and 15.7% for flexible devices are achieved. Further electrode modifications and integration of transparent TENGs synergistically balance the above-bandgap photon harvesting and transparency in a broad wavelength range (380 − 1000 nm), yet significantly reduce the transmittance in the near-infrared wavelength range (1000 − 2500 nm) of hybrid devices. The hybrid devices simultaneously provide high visible light transparency, good color fidelity, efficient heat resistance and possibility to integrate on rigid and flexible substrates. The hybrid devices attain a high solar conversion efficiency of 10.1% under 1 sun, indicating efficient light-to-electricity conversion (a maximum electrical power output: 101 W m−2) on sunny days. The hybrid devices can also generate a maximum electrical power output of 2.62 W m−2 through waterdrop energy conversion, implying complementary green electricity production on rainy days. The controlled ambient temperature and specific transmittance windows provided by the hybrid devices sustain plant growth and highlight their great potential in agricultural applications. Gratifyingly, this work demonstrates the first example of ST-PSC/TENG hybrid systems for scaling up renewable power generation in different weather conditions, considering architectural and agricultural applications.

Benzotriazole-containing fluorinated acrylic polymer coatings with high thermal stability, low surface energy, high visible-light transparency, and UV-blocking performance

Benzotriazole-containing fluorinated acrylic polymer coatings with high thermal stability, low surface energy, high visible-light transparency, and UV-blocking performance

Three modes of the nonstationary holographic current excitation in a gallium oxide crystal

We report the nonstationary holographic current excitation in a β-Ga2O3 crystal at light wavelength . The material demonstrates insulating properties and high transparency for visible light, but this, however, does not prevent the dynamic space-charge grating formation and the holographic current observation for various external electric fields —zero, dc and ac ones. The signal amplitude is measured and analyzed vs. the frequency of phase modulation, spatial frequency and electric field value. The main photoelectric parameters such as specific photoconductivity, sensor responsivity and diffusion length of carriers are determined for the blue region of spectrum.

Flexible, broadband, super-reflective infrared reflector based on cholesteric liquid crystal polymer

Cooling indoor spaces in hot weather conditions requires a significant amount of energy. To reduce energy consumption, light control of windows and facades in buildings is a great way. In this study, we propose a facile method to fabricate a flexible cholesteric liquid crystal (CLC) polymer reflector that can control the reflection of infrared (IR) light selectively without interfering with visible light. To this end, we fabricated a flexible super-wideband IR reflector using right- and left-handed chiral reactive mesogens. The fabricated IR reflector exhibited several desirable properties, including thinness, high mechanical stability and flexibility, strong durability, solvent- and acid resistance, high transparency, and low haze in visible light. The fabricated IR reflector was observed to reduce the indoor temperature by 6 °C compared to the outside temperature. This proves that, by insulating the incident heat, the proposed IR reflector can be utilized to maintain low indoor temperatures in working and living spaces. The flexible and super-reflective CLC film reported in this study is expected to be a promising candidate in several applications, including anti-IR devices, energy-saving windows for cars, and facades of modern buildings.

Organic diradicals enabled N-type self-doped conjugated polyelectrolyte with high transparency and enhanced conductivity

Conjugated polyelectrolytes (CPEs) have achieved vast success in organic electronics due to their appealing opt-electrical properties and convenient solution-processability. However, most of the existing n-type CPEs commonly exhibit distinct light capture in visible region. The attainment of novel n-type CPEs possessing both high electron conductivity and high visible light transparency is significant while still challenging. Herein, optimized amount of organic diradicals achieved by benzobisthiadiazo (BBT) unit are intentionally introduced into the backbone of the representative wide-band-gap polyfluorene-based conjugated polyelectrolyte via ternary copolymerization. The incorporation of diradical canonical structure could promote the quinoid resonance of conjugated skeleton, leading to increased self-doping effect. Consequently, the copolymerized CPE exhibits high visible light transmittance (AVT over 85%) and enhanced electron conductivity compared to the referenced CPE. The fabricated organic solar cell devices with the new-designed polyelectrolyte as the cathode interface layer can achieve high power conversion efficiencies of more than 16%, which is not susceptible to the thickness up to 50 nm. This work provides a feasible molecular modification strategy via organic diradicals regulation to obtain high performance n-type self-doped conjugated polyelectrolytes.

High-performance and stable inverted perovskite solar cells using low-temperature solution-processed CuNbOx hole transport layer

For a typical perovskite solar cell (PSC), the hole transport layer (HTL) plays a vital role in determining device performance and stability. Herein, for the first time, we demonstrate that a low-temperature solution-processed copper-niobium oxide (CuNbOx) thin film, consisting of CuNbO3 and CuNb2O6 phases, can serve as an efficient HTL to develop PSCs with high-performance and long-term stability simultaneously. The CuNbOx thin film possesses high optical transparency in visible light, well-matched energy levels with perovskite, and excellent hole extraction capability from the perovskite layer. By optimizing the precursor concentration, the CuNbOx-based device reaches the best power conversion efficiency (PCE) of 16.01% with negligible hysteresis. In comparison, the control device based on the extensively studied PEDOT:PSS HTL shows an obviously lower PCE of 10.13%. Besides exhibiting significant improvement in photovoltaic performance, our CuNbOx-based device also shows much enhanced long-term stability than the control device. After 1000 h of storage in air without encapsulation, the CuNbOx-based PSCs maintains ~78% of their initial efficiency, whereas the PCE of PEDOT:PSS-based PSCs drops to ~44% of the initial value. Overall, this study suggests that the utilization of the inorganic CuNbOx thin film as the HTL provides a novel route for fabricating low-cost, high-performance, and stable PSCs.

Mechanism for transmittance light tunable property of nanocrystalline Eu-doped SmB6: Experimental and first-principles study

Binary nanocrystalline rare-earth hexaboride is regarded as one of the promising optical absorption materials that possess the high transparency for visible light and the strong absorption for NIR due to the effects of localized surface plasmon resonance. In present work, we experimentally investigated the structural and optical absorption of ternary nanocrystalline Eu-doped SmB6 powder. As a result, it is found that the reaction temperature as an important factor not only refines the grain size, but also improves the powder dispersion of synthesized samples. The optical absorption results reveal that the transmittance wavelength of nanocrystalline SmB6 increases from 696 nm to exceeding 1000 nm with the Eu doping content increasing to x = 0.8. Theoretically, in order to study the transmittance wavelength tunable mechanisms of nanocrystalline Eu-doped SmB6, the electronic structure, density of states and energy loss function were calculated by first-principle calculation. It shows that the Eu2+ doping into SmB6 effectively reduces the plasma frequency excitation energy from 1.48 to 1.25 eV and leads to the transmittance wavelength redshift toward a higher wavelength. Based on above meaningful studies, present work is helpful for extension of optical applications of nanocrystalline SmB6 powder.

Thermal evolution of point defects in indium doped ZnO transparent conducting films

High visible light transparency and conductivity of ZnO enable the use of its material as transparent conducting films, in which point defects are vitally important for determining its optoelectronic properties. Herein, Indium doped ZnO thin films (ZnO:In) were prepared by radio-frequency magnetron sputtering technique. Thermal evolution of point defects and their effects on the microstructure and photoelectric properties of ZnO:In transparent conducting films were systematically investigated. The results show that thermal annealing induces the dissociation of extensive zinc interstitial clusters, causing their concentration gradually decreasing with increasing annealing temperature. Furthermore, when annealing at low temperature (≤ 500°C), the concentration of oxygen vacancy and zinc vacancy defects also decreases with increasing temperature. However, after annealing at higher temperature (600 and 700°C), additional vacancy defects are generated due to the evaporation of zinc and oxygen atoms from the film surface. It is demonstrated that the evolution of point defects caused by thermal annealing directly affects the microstructure and photoelectric properties of ZnO:In transparent conducting films.

High conductivity along with high visible light transparency in Al implanted sol-gel ZnO thin film with an elevated figure of merit value as a transparent conducting layer

Abstract In this work, sol–gel ZnO thin films were implanted with Al ions of various fluences to study their electrical transport properties as transparent conducting oxide (TCO) layers. Additionally, formation of structural defects and modifications of the optical emission properties due to implantation have been investigated extensively to correlate the resultant electrical properties. By varying the ion fluence over two orders of magnitude from 1 × 1013 to 6 × 1015 ions/cm2, interestingly the electrical transport properties have been seen to be degraded in an unexpected manner as soon as Al is implanted and beyond a certain fluence (5 × 1013 ions/cm2), the electrical properties begin to improve. For the highest fluence (6 × 1015 ions/cm2), the sheet resistance is found to be 156 Ω/sq with an average visible transmission of 82%. The figure of merit value of our Al implanted ZnO film for an Al fluence of 5 × 1015 ions/cm2 is the highest till date, which may be prospective as a TCO layer. Detailed investigation on the evolution of the electrical and photoluminescence properties with an increase in the Al ion fluence reveals that zinc vacancy type defects are formed in large number which on healing produces further higher conductivity in the films.