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Thermochromic Oxide-Based Thin Films and Nanoparticle Composites for Energy-Efficient Glazings
摘要： Today’s advances in materials science and technology can lead to better buildings with improved energy efficiency and indoor conditions. Particular attention should be directed towards windows and glass facades—jointly known as “glazings”—since current practices often lead to huge energy expenditures related to excessive inflow or outflow of energy which need to be balanced by energy-intensive cooling or heating. This review article outlines recent progress in thermochromics, i.e., it deals with materials whose optical properties are strongly dependent on temperature. In particular, we discuss oxide-based thin surface coatings (thin films) and nanoparticle composites which can be deposited onto glass and are able to regulate the throughput of solar energy while the luminous (visible) properties remain more or less unaltered. Another implementation embodies lamination materials incorporating thermochromic (TC) nanoparticles. The thin films and nanocomposites are based on vanadium dioxide (VO2), which is able to change its properties within a narrow temperature range in the vicinity of room temperature and either reflects or absorbs infrared light at elevated temperatures, whereas the reflectance or absorptance is much smaller at lower temperatures. The review outlines the state of the art for these thin films and nanocomposites with particular attention to recent developments that have taken place in laboratories worldwide. Specifically, we first set the scene by discussing environmental challenges and their relationship with TC glazings. Then enters VO2 and we present its key properties in thin-film form and as nanoparticles. The next part of the article gives perspectives on the manufacturing of these films and particles. We point out that the properties of pure VO2 may not be fully adequate for buildings and we elaborate how additives, antireflection layers, nanostructuring and protective over-coatings can be employed to yield improved performance and durability that make TC glazings of considerable interest for building-related applications. Finally, we briefly describe recent developments towards TC light scattering and draw some final conclusions.
关键词： thermochromism,vanadium dioxide,thin film,energy-efficient glazing,coating,sputter deposition,nanoparticle
更新于2025-09-23 15:21:01
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Enhanced Thermochromic Properties of Vanadium Dioxide (VO2)/Glass Heterostructure by Inserting a Zr-Based Thin Film Metallic Glasses (Cu50Zr50) Buffer Layer
摘要： Vanadium dioxide (VO2) with reversible metal–insulator transition (MIT) is one of the most promising energy-efficient materials. Especially for VO2-based smart windows, the visible transmittance and solar modulation ability are the most critical parameters. However, VO2 thin films that are directly deposited onto glass substrates are of poor crystallinity and MIT performance, limiting the practical applications of VO2/glass heterostructures. In this paper, a buffer layer of Cu50Zr50 was introduced to build a novel Zr-based thin film metallic glass (VO2/Cu50Zr50/glass) with multilayer structures for thermochromic applications. It is observed that the insertion of a Cu50Zr50 buffer layer with appropriate thickness results in a clear enhancement of crystalline quality and MIT performance in the VO2/Cu50Zr50/glass thin films, compared with the single-layer VO2/glass thin films. Moreover, the VO2/Cu50Zr50/glass bi-layer films exhibit better optical performance with enhanced solar modulation ability (?Tsol = 14.3%) and a high visible transmittance (Tvis = 52.3%), which represents a good balance between ?Tsol and Tvis for smart window applications.
关键词： Cu50Zr50 buffer layers,metal–insulator transition,vanadium dioxide thin film,thermochromic property,smart window
更新于2025-09-10 09:29:36
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Pressure and Temperature Dependence of Field-Induced Oscillation in Two-Terminal Device Based on Vanadium Dioxide Thin Film
摘要： In this paper, we investigated the pressure and temperature dependence of the frequency and amplitude of the ?eld-induced oscillation created in a two-terminal device based on a vanadium dioxide (cid:2) thin ?lm. First, a simple oscillation circuit was constructed using a VO2-based two-terminal (VO2 device, a standard resistor, and a DC power supply. Then, the frequency and amplitude variation of the ?eld-induced oscillation was observed for pressure changes applied to the VO2 device in a pressure chamber. This variation of the oscillation characteristics was also examined for ambient temperature changes applied to the VO2 device using a plate heater. When the chamber pressure increased from 0 to 5 MPa with a step of 1 MPa at 25 (cid:3)C, the oscillation frequency increased from ～592 to ～739 kHz, and the oscillation amplitude decreased from ～12.60 to ～11.40 V. Similarly, when the heater temperature increased from 25 to 50 (cid:3)C (step: 5 (cid:3)C) without applied pressure, the oscillation frequency increased from ～592 to ～819 kHz, and the oscillation amplitude decreased from ～12.60 to ～7.16 V. Owing to linear pressure and temperature responses of the VO2 oscillation, the pressure and temperature sensitivities of the oscillation frequency and amplitude could be obtained as four different constant coef?cients from the measurement results. These coef?cients can be directly utilized for simultaneously measuring pressure and temperature variation applied to the VO2 device, which can be bene?cially applied to localized temperature and pressure sensing at a very small area less than 1 mm2.
关键词： Vanadium Dioxide,Thin Film,Sensor,Field-Induced Oscillation
更新于2025-09-09 09:28:46