Cesium Tungsten Bronze Research Articles

Properties and Factors of CsxWO3 Slurry for Building Glass with High Visible Light Transmission and Outstanding Near-Infrared Insulation.

This study is dedicated to the development of a new type of cesium tungsten bronze energy-saving laminated glass and explores its application in insulating glass combinations, offering innovative ideas and practical solutions for advancing energy-saving glass technology. Experimental results show that both CsxWO3 (CWO) dispersions exhibit good visible light transmittance and near-infrared shielding properties, with CWO1 demonstrating superior shielding in the 650-950 nm range, attributed to differences in shape and size distribution and verified by simulations using the Drude-Lorentz model and the finite element method.

Optimizing Spectral Properties of Cesium Tungsten Bronze Films Doped with Silver Nanowires Based on the Machine Learning Method

Optimizing Spectral Properties of Cesium Tungsten Bronze Films Doped with Silver Nanowires Based on the Machine Learning Method

Poly(lactic Acid)/Cesium Tungsten Bronze Fibers with Good Dyeability and High Photothermal Conversion Performance

Poly(lactic Acid)/Cesium Tungsten Bronze Fibers with Good Dyeability and High Photothermal Conversion Performance

In-situ growth of Cs0·33WO3@ATO composite material with enhanced NIR shielding rate for energy-saving coating

Driven by the global goal of “carbon neutrality”, energy conservation, emission reduction and low-carbon development have become important research directions. Transparent thermal insulation materials can effectively shield near-infrared radiation while maintaining high visible light transmittance, making them widely applicable in building energy conservation. In this paper, antimony-doped tin oxide (ATO) and cesium tungsten bronze (CsxWO3, or CWO) are chosen to be composited in order to solve the problems of the poor shielding effect of ATO for short-wavelength near-infrared (NIR) light and the unsatisfactory shielding effect of CWO for long-wavelength NIR light. Therefore, in this study, we employed a one-step hydrothermal method to form a novel CWO@ATO core-shell structure to combine the advantages of both ATO and CWO. By adjusting the composite ratio of ATO and CWO, both the physical and electronic stucutres are effectively tuned to promote the optical modulation in a broad bandwidth. Enventually, the core-shell structured composite exhibit an excellent near-infrared blocking property, surpassing the pure ATO by 27.8 % in the wavelength region of 780∼1500 nm while improving by 14.9 % compared to CWO in the long wavelength between 1500 and 2500 nm. Furthermore, the prepared CWO@ATO core-shell structure repesents near-infrared shielding rate as high as 93.1 % in the full NIR spectrum, and possesses an overall thermal insulation coefficiency (THI) of 9.33 in the full range from 780 nm to 2500 nm, which is substantially larger than that of pure ATO and CWO by a factor of 2.37 and 3.05, respectively. This core-shell structure engineering realizes the utilization of complementary advantages of ATO and Cs0·33WO3 materials, providing a new method to improve the near-infrared performance of energy-saving glass coating, and having broad application prospects in the field of low-carbon buildings.

Enhancing NIR Shielding Properties of Au/CsWO3 Composite via Physical Mixing and Solvothermal Processes.

This research aims to enhance the near-infrared (NIR) shielding ability of cesium tungsten bronze (CsWO3) by increasing the spectral absorption in this region through the incorporation of gold nanorods (AuNR). Two approaches were used to prepare the composite materials: physical mixing and solvothermal process. The effects of gold nanorods content on the crystalline size, particle size, shape, and optical properties of the composite were investigated systematically using DLS, TEM, XRD, and UV-Vis spectroscopy techniques, respectively. The physical mixing process synergizes AuNR and CsWO3 into a composite which has better NIR absorption than that of neat AuNR and CsWO3 nanorods. A composite with 10 mol% of AuNR shows the highest NIR absorption ability due to the surface plasmon resonance and energy coupling between Au and CsWO3. With the solvothermal process, the CsWO3 nanorods grow up to 4-7 microns when the AuNR content increases to 0.8 mol% due to the incorporation of the Au atoms. The microsized CsWO3 rods have superior NIR shielding property compared to other conditions, including the AuNR+CsWO3 nanocomposite with 10 mol% of AuNR from the physical mixing process.

Rational Cationic Disorder in Hexagonal Cesium Tungsten Bronze Nanoparticles for Infrared Absorption Materials.

Hexagonal cesium tungsten bronze (Cs0.33WO3) nanoparticles (NPs) have attracted attention for their potential applications in near-infrared (NIR) absorbing materials. However, the insufficient Cs doping in Cs0.33WO3 NPs has limited their NIR absorbing capabilities and practical stability. In this study, we demonstrate the transition pathway from intermediate W-defective Cs0.33WO3 NPs synthesized by flame spray pyrolysis to cationic (Cs, W)-disordered Cs0.33WO3 NPs prepared through appropriate heat treatments. Direct atomic observations reveal the basal shear and prismatic (Cs, W)-defective planes, which contributed to the disorder of full Cs doping in Cs0.33WO3 NPs. The obtained Cs0.33WO3 NPs with cationic disorder exhibited enhanced practical performance compared with conventional Cs0.33WO3 NPs. Therefore, the developed approach that regulates cationic disorder enables the rational design of defective metal oxides for a variety of applications, including NIR absorbing materials.

Boosted near-infrared shielding properties of cesium-tungsten bronze based on solid state reaction with optimized precursor

Cesium doped tungsten bronze (CWO) nanoparticles can selectively keep high transmittance in the visible while presenting significant shielding rate in the near-infrared region. How to further improve the optical properties of CWO based on solid state method is crucial to the industry production. Based on changing the particle size and morphology of WO3 precursors, cesium-tungsten bronze powders with different dispersivity and concentrations of Cs+ doping were successfully prepared by solid-phase method. The characterization analysis reveals that the precursors with appropriated surface area and morphology are significant to improve the dispersivity of CWO nanocrystal and increase the density of free carriers, thereby improving the small polariton absorption performance and the local surface plasmon resonance effect. The result provides an effective strategy to boost the optical property of CWO nanocrystal synthesized by optimizing the morphology and size of precursor, which is important to the industry production and practical applications in the field of energy-saving window films.

CWO/SiO2 spectral beam splitter coating for photothermal synergetic catalysis: Design and development

Solar-energy-driven hydrogen production from biomass is a key technology for green hydrogen production. Photothermal synergistic catalysis is an effective means to enhance biological hydrogen production. In this study, a spectral beam splitter coating (SBSC) adapted for photothermal synergetic catalysis is designed and developed based on cesium tungsten bronze (CWO) and silicon dioxide (SiO2) in a sol–gel system. The CWO/SiO2 SBSC exhibits short-wavelength transmittance up to 85.7 % and absorption of near-infrared (NIR) light up to 91.3 % by adjusting the lifting speed, filling factor, and curing temperature. Evaluation model calculations reveal that the CWO/SiO2 SBSC can significantly improve the hydrogen production rate when the reaction solution temperature is 80 °C and that the integrated solar energy conversion efficiency is 3.7 times that without the SBSC. The results demonstrate the high durability of the CWO/SiO2 SBSC as well as its promising application scope in the photothermal synergetic catalysis of biomass hydrogen.

Study on effect of vanadium doping in cesium tungsten bronze system and application in HER

Increasing demand for energy and the crisis of fossil fuels have led researchers to search for an alternative energy source. Hydrogen is the cleanest energy source producing water as fuel cells exhaust. However, producing hydrogen could be crucial as only some active catalysts produce pure hydrogen. The expense due to the scarcity of the state-of-the-art catalyst (platinum) for the Hydrogen Evolution Reaction (HER) is the main reason for the higher price of pure hydrogen as a fuel. In our present research, we chose the less expensive cesium tungsten bronzes (CTB) doped with various percentages of vanadium (5 mol% - 20 mol%) to study their HER performance. The materials were prepared hydrothermally at 180 °C at different reaction times. XRD revealed that, upon increasing the vanadium amount, the hexagonal phase of the CTB is transformed to the cubic phase at a higher reaction time. However, the hexagonal phase was retained after vanadium introduction with a lower reaction time. FT-IR, Raman, EDX, SIMS, XPS, and XRF spectroscopy confirmed the incorporation of vanadium into the bronze system. Vanadium-doped samples showed enhanced HER activity compared to the pure CTB. The 20% vanadium-doped hexagonal bronze showed the best HER performance in 0.5 M H2SO4 among all the vanadium-doped materials, which lowered the HER potential of the pure CTB (-0.665 V vs RHE) to -0.288 V vs RHE at -10 mA cm−2. This increase in activity was correlated with a higher surface area, higher electrochemical surface area, faster reaction kinetics with a lower Tafel slope, and a small charge-transfer resistance of the samples after V5+ incorporation compared to the pure CTB.

One-step assembly of organic-inorganic hybrid coatings with superior thermal insulation, sustainable antifogging and self-cleaning capabilities

Multifunctional transparent glass integrating energy-saving and antifogging properties has receiving continuous attention in basic research and practical applications, which is still plagued by the lack of simple and general methods for low-cost and large-area fabrication. Herein, a multifunctional window with high thermal insulation, antifogging, and self-cleaning functions is rationally fabricated via coating a mixture of polyacrylic acid (PAA), polypropylene glycol (PPG), 3-glycidyloxypropyltrimethoxysilane (KH-560), and cesium tungsten bronze (CWO) nanoparticles on a monolayer film. The synergistic effect between the plentiful hydroxyl/carboxyl groups of PAA/PPG and the nano-textured surface induced by CWO nanoparticles enabled the monolayer film to exhibit superhydrophilic, self-cleaning and antifogging capabilities. The film maintains its antifogging properties even after 80 rubbings of dust-free cloth and 120 days of exposure tests at room temperature. Moreover, the as-prepared window can reduce the indoor temperature by 15.8 °C compared to a normal window at noon. The energy simulation results demonstrate that such windows can reduce energy consumption by 18.9 % in local cities compared to traditional windows. The high visible light transmittance, low haze, stable and durable antifogging ability, distinguished energy-saving effect and climate adaptability, as well as the solution-based process of this multifunctional window make it promising for architectural and automotive glass applications.

One-step ball-milling synthesis of cesium tungsten bronze nanoparticles and near-infrared shielding performance

Tungsten bronze (MxWO3) materials have been widely used as thermal insulation for architectural glass because of their higher near-infrared (NIR) light shielding capacity. To solve the problems encountered in solvothermal preparation with high costs and low yields, this study has developed a facile, eco-friendly, effective, but low-cost method, with no need for any annealing process, for promoting the large-scale fabrication of cesium tungsten bronze (CsxWO3, x = 0.32) nanomaterials for potential thermal insulation windows applications. In the proposed ball-milling process, the tungstic acid material could be reduced to hydro tungsten bronze (HxWO3) by cellulose, while the cesium ions (Cs+) could be gradually incorporated into the interspace until the formation of Cs0.32WO3 (Cs/W atomic ratio = 0.32), with an average particle size of ∼33 nm after a 15 h ball-milling process. The reaction mechanism has been investigated in detail via particle structural analysis and optical performance characterization. The obtained Cs0.32WO3 nanoparticles are dispersed in a solution composed of surfactant (s) and polymer (s) which can form a thin film with a thickness of about 2 μm on a glass substrate, by a spinning coating or casting method, to exhibit high visible (Vis) light transmittance (T566nm = 72.6%), and excellent NIR-shielding capability (T1388nm = 5.3%), reflected by good heat-insulating performance in practice use. This work will pave a new path for large-scale production of Cs0.32WO3 nanomaterials with low costs and high performance, beneficial for practical applications in energy-saving glass coatings.

Thermochromic Ni(II) Organometallics With High Optical Transparency and Low Phase-Transition Temperature for Energy-Saving Smart Windows.

Thermochromic smart windows with rational modulation in indoor temperature and brightness draw considerable interest in reducing building energy consumption, which remains a huge challenge to meet the comfortable responsive temperature and the wide transmittance modulation range from visible to near-infrared (NIR) light for their practical application. Herein, a novel thermochromic Ni(II) organometallic of [(C2 H5 )2 NH2 ]2 NiCl4 for smart windows is rationally designed and synthesized via an inexpensive mechanochemistry method, which processes a low phase-transition temperature of 46.3 °C for the reversible color evolution from transparent to blue with a tunable visible transmittance from 90.5% to 72.1%. Furthermore, cesium tungsten bronze (CWO) and antimony tin oxide (ATO) with excellent NIR absorption in 750-1500 and 1500-2600nm are introduced in the [(C2 H5 )2 NH2 ]2 NiCl4 -based smart windows, realizing a broadband sunlight modulation of a 27% visible light modulation and more than 90% of NIR shielding ability. Impressively, these smart windows demonstrate stable and reversible thermochromic cycles at room temperature. Compared with the conventional windows in the field tests, these smart windows can significantly reduce the indoor temperature by 16.1 °C, which is promising for next-generation energy-saving buildings.

Tungsten bronze CsxWO3 nanopowders doped by Ti to enhance transparent thermal insulation ability for energy saving

Cesium tungsten bronze (CsxWO3), a unique energy-saving material, has attracted great interest because of its excellent visible transmittance and near-infrared absorption. In order to improve its optical properties, the Ti doping modification was carried out in this work, and a series of Ti-doped CsXWO3 (Ti-CsxWO3) nanopowders were synthesized by a solvothermal reaction and post-annealing. The 1.71 at. % of Ti dopants achieved remarkable enhancement of both integral visible transmittance (Tlum, 380–780 nm) and near-infrared shielding efficiency (ΨNIR, 780–2500 nm) of CsxWO3. The Tlum and ΨNIR of the 1.71 at. % Ti-CsxWO3 polymer film reaches 63.87 % and 76.90 %, respectively, higher by 51.88 % and 65.00 % than those of the CsxWO3 film. The improvement of Tlum is attributed to the broadening of band gap and smaller size of the nanoparticles induced by Ti doping, and the enhanced ΨNIR would result from the increased free electron concentration and energy levels of impurities. The incorporation of Ti elements renders CsxWO3 a promising application in the field of energy saving.

One-step solvothermal synthesis of CsxWO3: Crystal growth regulation by halogen acids with generating oxygen vacancies and W5+ for improving transparent thermal insulation performance

Synthesis of cesium tungsten bronze (CsxWO3) nanorods with excellent near-infrared shielding performance by a one-step solvothermal method from cheap tungsten source is still challenging. In this work, small-sized CsxWO3 nanorods with excellent transparent thermal insulation performance were synthesized by a one-step solvothermal method. It was found that halogen acids played an important role in regulating the growth and microstructure of CsxWO3 nanorods. Moreover, different halogen acid can regulate the content of W5+=O and oxygen vacancies (VO) in CsxWO3 nanorods, which is helpful to further improve the near-infrared shielding performance of CsxWO3 particles. Compared with HF and HBr, the CsxWO3 nanoparticles synthesized under the regulation of HCl contain more VOs and W5+=O content, showing more excellent near-infrared shielding performance, and the as-prepared CsxWO3-PVA composite film exhibits low haze and high transparency, with the near-infrared light shielding rate at 1500 nm attaining to 97.7% when the visible light transmittance is 71.8%. The thermal insulation test results show that the CsxWO3-PVA composite film synthesized under the regulation of HCl can effectively reduce the indoor temperature by 6.9 °C under the irradiation of sunlight. After 100 cycles of thermal insulation tests, the near-infrared shielding and thermal insulation performance have not declined, showing excellent photothermal stability. This work is of great significance for promoting the industrial production of high-performance CsxWO3 nanoparticles and its application in energy-saving windows.

An energy-efficient and low-driving-voltage flexible smart window enhanced by POSS and CsxWO3

Smart windows with controllable visible and near-infrared (NIR) light transmittance are highly desirable for energy-saving buildings. Herein, we propose a hybrid polymer dispersed liquid crystal (PDLC) film for smart window applications, which combines dopants of polyhedral oligomeric silsesquioxane (POSS) and cesium tungsten bronze (Cs x WO 3 ). The low surface free energy of POSS and NIR absorption of Cs x WO 3 endow the film with enhanced electro-optical performance (ultra-low driving voltages, high contrast ratio and low optical haze value) and maneuverable light modulation in visible and NIR range. A model house equipped with the proposed film as smart windows reveals its outstanding light shielding and temperature regulating abilities that the indoor temperature rises less than 5 o C after irradiation for 10min under the experimental conditions. The research provides new opportunities for further development of energy-efficient smart windows, especially for cooling energy saving in buildings. • A hybrid PDLC film is proposed that can modulate the light passage in both visible and near-infrared ranges. • Cs x WO 3 is introduced to absorb the near-infrared radiation. • Both Cs x WO 3 and POSS can enhance the electro-optical properties of PDLC. • The as-fabricated film can regulate indoor temperature if used as smart windows.

Effects of crystal structure and morphology on the electrochromic properties of CsxWO3

Smart windows have been used to reduce indoor energy consumption by utilizing materials with excellent near-infrared absorption properties, among which cesium tungsten bronze CsxWO3 is one of the widely used materials. However, the stability of CsxWO3 during applications is a very challenging problem. The electrochromic technology can be used to solve it. Here, nano CsxWO3 with space group P63/mcm has been synthesized to study the effects of the crystal structure and morphology on the electrochromic properties by tailoring the reaction condition during the solvothermal process. The sizes of hexagonal and trigonal channels in WO6 framework change with the reaction condition of samples and reach to their maximum values at the highest Cs content. The cluster-shaped grains uniformly distribute in the sample with the highest Cs content. Both of the transmittance modulation range and coloration efficiency of this sample are about several times than those of other samples. The large-size channels in WO6 framework and rod-like cluster morphology facilitate the enhancement of electrochromic properties.

HPC-PAA hydrogel smart windows with and without Cs0.32WO3: High solar modulation ability and luminous transmittance

Hydroxypropyl cellulose (HPC) hydrogel is a promising material for fabricating energy saving smart windows. However, its lower critical solution temperature (LCST = 42 °C) is much higher than comfortable room temperatures. In this work, we applied surface polymerization of acrylic acid (AA) monomers on HPC chains and synthesized HPC-polyacrylic acid (PAA) hydrogels with precisely controllable LCST in the range of 23.0–42.0 °C. The fabricated HPC-PAA hydrogel smart windows exhibited excellent Tlum,22 °C of 91.8% and ΔTsol,22–40 °C of 73.7%, outperforming VO2 hydrogel composites and photothermal nanoparticles doped hydrogel smart windows. Meanwhile, cesium tungsten bronze (Cs0.32WO3) photothermal nanoparticles can be introduced to the HPC-PAA hydrogel matrix, and the near infrared (NIR) shielding ability of Cs0.32WO3 allowed significant reduction of NIR transmittance of the smart windows from 81.7% to 41.6% at 22 °C, and from 19.3% to 3.6% at 40 °C. Temperature regulation tests in model houses revealed outstanding heat-shielding performance of Cs0.32WO3 (0.4 wt%)/HPC-PAA hydrogel smart windows, especially compared with ordinary double-glass windows. Furthermore, the HPC-PAA hydrogel and Cs0.32WO3 (0.4 wt%)/HPC-PAA hydrogel are non-toxic, biocompatible, low-cost, suggesting their suitability for energy-saving smart window applications.

Doping Sodium Tungsten Bronze-Like (Na5W14O44) Near-Infrared Shielding Functional Units in Bulk Borosilicate Glasses for Energy-Saving Window Applications.

Tungsten bronze is an effective near-infrared (NIR) shielding material for fabricating energy-saving smart windows. While high-performing NIR-shielding glasses can be fabricated by coating a tungsten bronze film on window glasses, these glasses suffer a short lifespan due to the adhesion and degeneration of film. In this work, we show that tungsten bronze-like material Na5W14O44 can be distributed in the bulk glass matrix during the facile melt-quenching glass fabrication process under an air atmosphere, overcoming the limitations of film-based glasses. X-ray diffraction, Raman spectroscopy, and X-ray photoelectron spectroscopy confirmed the presence of tungsten bronze-like Na5W14O44 functional units in the SiO2-B2O3-NaF glass matrix. The addition of a small amount of H2WO4 and Sb2O3 is critical for the formation of Na5W14O44 functional units because H2WO4 provides W for Na5W14O44, and Sb2O3 acts as a reducing agent that helps the formation of W5+ in Na5W14O44 under an air atmosphere. Furthermore, the NIR-shielding ability can be tuned by adjusting the concentration of Sb2O3 in the range of 0-1.5 mol % and of H2WO4 in the range of 4-6 mol %. The optimized composition containing 1.25 mol % of Sb2O3 and 5 mol % of H2WO4 exhibits excellent NIR-shielding ability (ΔT = 62.8%), high visible light transmittance (Tmax = 67.7%), and excellent thermal insulation. This performance is comparable to cesium tungsten bronze film-based glasses and much better than soda lime glass and ITO glass under sun irradiation. This study sheds light on fabricating energy-saving windows in a simple and cost-effective way with flexibility for fine tuning of NIR-shielding performance.

Effects of patterned electrode on near infrared light-triggered cesium tungsten bronze/poly(vinylidene)fluoride nanocomposite-based pyroelectric nanogenerator for energy harvesting

Pyroelectric nanogenerators (PyNG) are crucial to convert waste heat into electrical energy. In this study, we develop PyNG device with screen-printed serpentine electrode (SRE) and we modify with cesium tungsten bronze (Cs0.33WO3). We incorporate Cs0.33WO3 into both the electrode and poly(vinylidene)fluoride (PVDF) layers. We investigate effects of Cs0.33WO3 on pyroelectric response and photothermal conversion and electrode pattern effects on the pyroelectric properties. The electrode pattern remarkably improves pyroelectric response in which SRE pattern with width of 2 mm (Sample 2 (S2)) presents the highest electrical current and power. Moreover, the PVDF/Cs0.33WO3 PyNG device possesses outstanding photothermal conversion and pyroelectric response in comparison to PVDF-based PyNG device. Particularly, temperature of the device with 7 wt% Cs0.33WO3 reaches 121 °C and it shows electrical output responses of 4.36 V and 214 nA. It also generates a power density of 23.28 μW/m2 at a loading resistance of 20 MΩ. The electrical energy PyNG device generate power liquid crystal display (LCD) and four light-emitting diodes (LEDs). Our PyNG device presents better pyroelectric properties than that of PyNG device in open literature. This study represents an alternative to design and develop PyNG devices to harvest solar energy.

Carbon-supported nano tungsten bronze aerogels with synergistically enhanced photothermal conversion performance: Fabrication and application in solar evaporation

Solar interfacial evaporation is an effective and sustainable strategy to solve the shortage of fresh water. Nowadays, fully converting the near-infrared light with significant thermal effect, and reducing the energy loss in evaporation stage are the key factors to achieve higher evaporation rate. Herein, the nano cesium tungsten bronze (Cs0.32WO3) with exceptional near-infrared absorption property was loaded on reduced graphene oxide-carbon nanotubes (rGO-CNTs) composite aerogel, drastically enhancing the evaporation efficiency from 61.0% to 85.9%, which can be explained by the remarkable synergistic effect between rGO-CNTs and nano Cs0.32WO3 in improving the photothermal conversion performance. As a result, the solar evaporators assembled by the fabricated rGO-CNTs-Cs0.32WO3 aerogels and corn straw grooves achieved an evaporation rate of 1.93 kg m−2 h−1, exceeding the previously-investigated carbon aerogels/foams, natural plants and tungsten-based compound systems. The characterization results reveal that the loading of nano Cs0.32WO3 contributes to the partial restoration of π-conjugated structure in rGC, increasing solar absorption and the corresponding thermal energy released by the lattice vibration. Meanwhile, the oxygen vacancies and carrier density of Cs0.32WO3 nanoparticles increase after compositing with rGC, which further enhances the local surface plasma resonances (LSPR) effect. Significantly, the hydrophilic functional groups and excellent wettability of composite aerogel and corn straw play crucial effect in accelerating water transport, activating water molecules and reducing evaporation energy consumption. In a word, the unique construction of rGO-CNTs-Cs0.32WO3 aerogels presents a novel approach for the design of solar-driven freshwater production system, the application expansion of nano tungsten bronze and carbon aerogels.