VO2/ZnO bilayer films with enhanced thermochromic property and durability for smart windows

It has been recently demonstrated that yttrium oxyhydride(YHO) films can exhibit reversible photochromic properties when exposed to illumination at ambient conditions. This switchable optical propertyenables their utilization in many technological applications, such as smart windows, sensors, goggles, medical devices, etc. However, how the composition of the films affects their optical properties is not fully clear and therefore demands a straightforward investigation. In this work, the composition of YHO films manufactured by reactive magnetron sputtering under different conditions is deduced in a ternary diagram from Time-of-Flight Elastic Recoil Detection Analysis (ToF-ERDA). The results suggest that stable compounds are formed with a specificchemical formula – YH<sub>2-δ</sub>O<sub>δ</sub>. In addition, optical and electrical properties of the films are investigated, and a correlation with their compositions is established. The corresponding photochromic response is found in a specific oxygen concentration range (0.45 < δ < 1.5) with maximum and minimum of magnitude on the lower and higher border, respectively.

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Tailoring Broad-Band-Absorbed Thermoplasmonic 1D Nanochains for Smart Windows with Adaptive Solar Modulation

ACS Applied Materials & Interfaces ◽

10.1021/acsami.0c21584 ◽

2021 ◽

Vol 13 (4) ◽

pp. 5634-5644

Author(s):

Min Guo ◽

Qiaoqi Yu ◽

Xingchi Wang ◽

Wanxuan Xu ◽

Yi Wei ◽

...

Keyword(s):

Broad Band ◽

Solar Modulation ◽

Smart Windows

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Development of PE/PCL Bilayer Films Modified with Casein and Aluminum Oxide

Molecules ◽

10.3390/molecules26113090 ◽

2021 ◽

Vol 26 (11) ◽

pp. 3090

Author(s):

Anita Ptiček Siročić ◽

Ana Rešček ◽

Zvonimir Katančić ◽

Zlata Hrnjak-Murgić

Keyword(s):

Mechanical Properties ◽

Thermal Properties ◽

Water Vapor ◽

Aluminum Oxide ◽

Water Vapor Permeability ◽

Vapor Permeability ◽

Mechanical And Thermal Properties ◽

Oxide Compound ◽

Bilayer Films ◽

Oxide Particles

The studied samples were prepared from polyethylene (PE) polymer which was coated with modified polycaprolactone (PCL) film in order to obtain bilayer films. Thin PCL film was modified with casein/aluminum oxide compound to enhance vapor permeability as well as mechanical and thermal properties of PE/PCL films. Casein/aluminum oxide modifiers were used in order to achieve some functional properties of polymer film that can be used in various applications, e.g., reduction of water vapor permeability (WVTR) and good mechanical and thermal properties. Significant improvement was observed in mechanical properties, especially in tensile strength as well as in water vapor values. Samples prepared with aluminum oxide particles indicated significantly lower values up to 60%, and samples that were prepared with casein and 5% Al2O3 showed the lowest WVTR value.

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High-Efficiency Responsive Smart Windows Fabricated by Carbon Nanotubes Modified by Liquid Crystalline Polymers

Crystals ◽

10.3390/cryst11040440 ◽

2021 ◽

Vol 11 (4) ◽

pp. 440

Author(s):

Yuan Deng ◽

Shi-Qin Li ◽

Qian Yang ◽

Zhi-Wang Luo ◽

He-Lou Xie

Keyword(s):

Carbon Nanotubes ◽

Liquid Crystalline ◽

Near Infrared ◽

High Efficiency ◽

Polymer Brush ◽

Light Transmittance ◽

Smart Window ◽

Vertical Orientation ◽

Smart Windows ◽

Conversion Materials

Smart windows can dynamically and adaptively adjust the light transmittance in non-energy or low-energy ways to maintain a comfortable ambient temperature, which are conducive to efficient use of energy. This work proposes a liquid crystal (LC) smart window with highly efficient near-infrared (NIR) response using carbon nanotubes grafted by biphenyl LC polymer brush (CNT-PDB) as the orientation layer. The resultant CNT-PDB polymer brush can provide the vertical orientation of LC molecules to maintain the initial transparency. At the same time, the smart window shows a rapid response to NIR light, which can quickly adjust the light transmittance to prevent sunlight from entering the room. Different from common doping systems, this method avoids the problem of poor compatibility between the LC host and photothermal conversion materials, which is beneficial for improving the durability of the device.

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Strong texture tuning along different crystalline directions in glass-supported CeO2 thin films by ultrasonic spray pyrolysis

Scientific Reports ◽

10.1038/s41598-021-81353-x ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Inti Zumeta-Dubé ◽

José Manuel García Rangel ◽

Jorge Roque ◽

Issis Claudette Romero-Ibarra ◽

Mario Fidel García Sánchez

Keyword(s):

Thin Films ◽

Spray Pyrolysis ◽

Spray Pyrolysis Technique ◽

Morphological Characteristics ◽

Ultrasonic Spray Pyrolysis ◽

Cost Effective ◽

Growth Direction ◽

Large Area ◽

Smart Windows ◽

Ultrasonic Spray

AbstractThe strong facet-dependent performance of glass-supported CeO2 thin films in different applications (catalysis, smart windows, etc.) has been the target of diverse fundamental and technological approaches. However, the design of accurate, cost-effective and scalable methods with the potential for large-area coverage that produce highly textured glass-supported CeO2 thin films remains a technological challenge. In the present work, it is demonstrated that under proper tuning conditions, the ultrasonic spray pyrolysis technique enables one to obtain glass-supported polycrystalline CeO2 films with noticeable texture along both the (100) and (111) directions, as well as with randomly oriented crystallites (no texture). The influence of flow rates, solution molarity, and substrate temperature on the texture and morphological characteristics, as well as optical absorption and Raman response of the deposited films, is evaluated. The obtained results are discussed on the basis of the combined dependence of the CeO2-exposed surfaces on the thermodynamic stability of the corresponding facets and the reaction kinetics, which modulate the crystallite growth direction.

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Optimal Control Strategies for Switchable Transparent Insulation Systems Applied to Smart Windows for US Residential Buildings

Energies ◽

10.3390/en14102917 ◽

2021 ◽

Vol 14 (10) ◽

pp. 2917

Author(s):

Mohammad Dabbagh ◽

Moncef Krarti

Keyword(s):

Energy Use ◽

Control Strategies ◽

Residential Buildings ◽

Residential Building ◽

Optimization Approach ◽

Optimal Controls ◽

Peak Demand ◽

Smart Windows ◽

Insulation Systems ◽

Rule Set

This paper evaluates the potential energy use and peak demand savings associated with optimal controls of switchable transparent insulation systems (STIS) applied to smart windows for US residential buildings. The optimal controls are developed based on Genetic Algorithm (GA) to identify the automatic settings of the dynamic shades. First, switchable insulation systems and their operation mechanisms are briefly described when combined with smart windows. Then, the GA-based optimization approach is outlined to operate switchable insulation systems applied to windows for a prototypical US residential building. The optimized controls are implemented to reduce heating and cooling energy end-uses for a house located four US locations, during three representative days of swing, summer, and winter seasons. The performance of optimal controller is compared to that obtained using simplified rule-based control sets to operate the dynamic insulation systems. The analysis results indicate that optimized controls of STISs can save up to 81.8% in daily thermal loads compared to the simplified rule-set especially when dwellings are located in hot climates such as that of Phoenix, AZ. Moreover, optimally controlled STISs can reduce electrical peak demand by up to 49.8% compared to the simplified rule-set, indicating significant energy efficiency and demand response potentials of the SIS technology when applied to US residential buildings.

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Cover Picture: Self-Assembled Metal Oxide Bilayer Films with “Single-Crystalline” Overlayer Mesopore Structure (Adv. Mater. 8/2007)

Advanced Materials ◽

10.1002/adma.200790029 ◽

2007 ◽

Vol 19 (8) ◽

Author(s):

T. Brezesinski ◽

M. Antonietti ◽

B. M. Smarsly

Keyword(s):

Metal Oxide ◽

Single Crystalline ◽

Bilayer Films ◽

Mesopore Structure ◽

Self Assembled

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Full-frame and high-contrast smart windows from halide-exchanged perovskites

Nature Communications ◽

10.1038/s41467-021-23701-z ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

You Liu ◽

Jungan Wang ◽

Fangfang Wang ◽

Zhengchun Cheng ◽

Yinyu Fang ◽

...

Keyword(s):

Contrast Ratio ◽

High Contrast ◽

Smart Window ◽

Frame Size ◽

Smart Windows ◽

Ideal Solutions ◽

Ion Gel ◽

And Control ◽

Colour Rendering ◽

Perovskite Photovoltaic

AbstractWindow glazing plays an essential role to modulate indoor light and heat transmission, which is a prospect to save the energy cost in buildings. The latest photovoltachromic technology has been regarded as one of the most ideal solutions, however, to achieve full-frame size (100% active area) and high-contrast ratio (>30% variable in visible wavelength) for smart window applicability is still a challenge. Here we report a photovoltachromic device combining full-transparent perovskite photovoltaic and ion-gel based electrochromic components in a vertical tandem architecture without any intermediated electrode. Most importantly, by accurately adjusting the halide-exchanging period, this photovoltachromic module can realize a high pristine transmittance up to 76%. Moreover, it possesses excellent colour-rendering index to 96, wide contrast ratio (>30%) on average visible transmittance (400-780 nm), and a self-adaptable transmittance adjustment and control indoor brightness and temperature automatically depending on different solar irradiances.

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