SOLAR ENERGY MATERIALS AND SOLAR CELLS
·
2012
·
IF 4.542
Jing Du,Yanfeng Gao,Zhang Chen,Litao Kang,Zongtao Zhang,Hongjie Luo
Application of VO 2 to smart windows calls for an enhancement of both luminous transmittance ( T lum ) and solar transmittance modulation (Δ T sol ). These two properties are related to optical constants , microstructure and film thickness. In this article, VO 2 -based films with increased microroughness are prepared by polymer assisted deposition , and ZnCl 2 is added to the precursor solution to control the microstructure of the films. Addition of ZnCl 2 increases the microroughness of films through phase separation, which largely decreases the refraction index and the reflectivity of the films, resulting in enhanced luminous transmittance and solar transmittance modulation; two films with balanced optical performance show T lum =50.5% and Δ T sol =11.3%, and T lum =59.3% and Δ T sol =10.5%, respectively. Moreover, this kind of microstructure control has no influence on doping VO 2 , which is proven by the deposition and characterization of W-doped VO 2 -based films. By the formation of a W-doped VO 2 /F:SnO 2 /glass multilayer stack, a film shows excellent thermochromic properties and low emissivities; typically, a film with a phase transition temperature, T lum , Δ T sol of 43.4 °C, 30.0%, 8.82%, respectively, and emissivity of 0.20 for monoclinic and 0.33 for rutile phase is successfully prepared.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF NON-CRYSTALLINE SOLIDS
·
2013
·
IF 1.597
Yuankai Liu,Haizheng Tao,Xinhong Chu,Meinan Wan,Jianhua Bao,Xiujian Zhao
Based on the thermochromic properties of VO 2 , wide applications such as smart windows have been investigated in the world. Using the sol–gel method, series of thermochromic films, including the pure and W-doped VO 2 films, were fabricated on quartz substrate. WCl 6 was used as the source of tungsten . Measurements of temperature dependent transmitting spectra indicated that obvious enhancement of transmitting variance between 30 and 90 °C can be realized through the addition of tungsten. In addition, based on the comparison of thermal hysteresis loops of the W-doped and undoped thermochromic films, the sharpening of temperature width and steepening of temperature–transmittance curves can be clearly seen from the W-doped thermochromic films, which indicated the improved phase change quality compared with the undoped ones. Therefore, the improvement of phase change quality has been realized successfully through the addition of tungsten compound into the thermochromic VO 2 films.
研究领域:
材料科学
·
物理学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2017
·
IF 3.133
Meinan Wan,Baoshun Liu,Shuo Wang,Lingting Hu,Youjia He,Haizheng Tao,Xiujian Zhao
Monoclinic (M1) VO 2 film has potential applications in thermochromic modulators owing to the particular optical performance caused by phase transition. However, its controllable preparation is very difficult due to the multivalence of V element. Here, we studied a sol-gel process followed by annealing in a closed vaccum furnace containing NH 3 atmosphere, and discussed the formation mechanism of M1-phase VO 2 films. Thermochromic M1-phase VO 2 thin films can be fabricated under the base pressure of 600–2000 Pa with the annealing temperature at 470–590 °C for more than 0.5 h, and the optimal condition is at 1000–2000 Pa and 500–530 °C for 0.5 h, by synthetically considering their luminous transmittance ( T lum ), solar modulation efficiency ( ΔT sol ), and modulation efficiency at 2000 nm ( ΔT 2000nm ). The M1-phase VO 2 thin film generally exhibits the optical properties with T lum ≈ 39–41%, ΔT sol ≈ 7.7% and ΔT 2000nm ≈ 50%. A higher base pressure introduces more oxygen to remove polymers in precursors, enhancing the transparency of films. Improving the temperature or the duration promotes the growth of VO 2 crystallite with limits. However, inappropriate base pressure, temperature or duration will reduce or oxidize the VO 2 films, resulting in the inferior thermochromic properties. According to thermal and XPS analysis , NH 3 can act as a reductant to prevent oxidation of VO 2 films during the annealing process. This convenient heat treatment method to synthesize M1-VO 2 films may provide a useful and practical technique for the production of VO 2 -based smart window and optical devices.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2022
·
IF 7.392
Jiachen Qian,Bin Li,Shouqin Tian,Baoshun Liu,Xiujian Zhao
VO 2 -based thermochromic smart windows have attracted much attention due to their promising energy-saving effects. However, the high phase transition temperature ( T c , 68 °C), low luminous transmittance ( T lum , <40%) and solar energy modulation efficiency (Δ T sol , <10%) hindered their practical application. In order to improve these deficiencies simultaneously, the photothermal W 18 O 49 nanorods were introduced into VO 2 based nanothermochromic films in this work. The obtained film exhibited enhanced thermochromic performance ( T lum = 82.5%, Δ T sol = 10%) due to the incorporation of W 18 O 49 nanorods. And T lum of 63.3% and Δ T sol of 18.6% were presented for the bilayer film, which is one of the best reported performances for VO 2 films to date. In particular, the bilayer film exhibited an obvious energy saving effect with a reduction of 21.1 °C in indoor temperature compared with normal glass due to its excellent thermochromic properties. In addition, the thermochromic characteristics of VO 2 -W 18 O 49 -polyvinylpyrrolidone (PVP) composite films could be trigged at lower temperature than that of VO 2 film due to the additional thermal energy generated by the absorption of near-infrared light by W 18 O 49 nanorods. Therefore, the outstanding performance and the easily scaled solution-based synthesis route would facilitate the practical application of VO 2 -based smart windows.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
ZEITSCHRIFT FUR ANORGANISCHE UND ALLGEMEINE CHEMIE
·
2022
·Vol. 648
·期 14
·e202200132
·
IF 1.414
Rui Pei,Xinguo Ma,Changcun Han,Zhifeng Liu,Zhengwang Cheng,Xiaoru Dong
Reducing the phase transition temperature ( T c ) of VO 2 films to achieve the application in the field of Smart Home is still a challenge. Thus, in the work, the ultra-thin VO 2 films with different Mo doping amounts were successfully prepared by an economic sol-gel method and atmosphere annealing, aiming to further investigate the mechanism of the decrease of T c . The results show that the VO 2 films with 3 at % Mo doping possess the T c of 29.5 °C. Notedly, in the as-prepared films, the maximum transmittance in the visible region ( T vis ) is 46.3 % and the solar direct transmittance ( T sol ) is 45.8 %. According to the XPS spectra, it is confirmed that the Mo doping prominently induces the valence change of V ions from +4 to +3, inhibiting the strain in the phase transition process of VO 2 films, and leading to the decrease of T c . Our work will provide a feasible solution for reducing the T c of the ultra-thin VO 2 films.
研究领域:
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Bin Li,Shouqin Tian,Jiachen Qian,Senwei Wu,Baoshun Liu,Xiujian Zhao
Thermochromic VO 2 -based smart windows are considered as a highly promising building envelope to reduce building energy consumption. However, the inherent unsatisfactory optical performance hindered its practical applications and nanocomposite films are testified to be the most promising strategy addressing this issue, while uniformly dispersing nanoparticles is often a challenge. Herein, a facile in situ method was proposed to directly fabricate highly dispersed VO 2 nanoparticles (HD-VN) on a glass surface from the VOC 2 O 4 ·xH 2 O aqueous solution to achieve the high-optical performance VO 2 film (HD-VN film). The forming mechanism of HD-VN was fully elucidated and HD-VN was generated via the sintering process from the irregular VO 2 particles derived from the decomposition of polyvinyl pyrrolidone (PVP). The HD-VN film showed excellent luminous transmittance ( T lum ) of 72.5% and solar energy modulation efficiency (Δ T sol ) of 10.1%, the former was attributed to the reduced refractive index which led to a reduced reflectance of HD-VN film, and the latter was ascribed to the localized surface plasmon resonance (LSPR) behavior of the HD-VN. The simple and cost-efficient synthesis strategy would promote the application of VO 2 film in energy-efficient glazing, and also shed light on the structures’ design applied to the field of optics, catalysts, and sensors.
研究领域:
材料科学
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能源技术
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2022
·Vol. 16
·期 1
·208
·
IF 3.748
Meinan Wan,Mo Xiong,Shouqin Tian,Xingzhu Chen,Bin Li,Xuesong Lu,Xiujian Zhao
VO2, as a promising material for smart windows, has attracted much attention, and researchers have been continuously striving to optimize the performance of VO2-based materials. Herein, nitrogen-incorporated VO2(M1) thin films, using a polyvinylpyrrolidone (PVP)-assisted sol–gel method followed by heat treatment in NH3atmosphere, were synthesized, which exhibited a good solar modulation efficiency (ΔTsol) of 4.99% and modulation efficiency of 37.6% at 2000 nm (ΔT2000 nm), while their visible integrated transmittance (Tlum) ranged from 52.19% to 56.79% after the phase transition. The crystallization, microstructure, and thickness of the film could be regulated by varying PVP concentrations. XPS results showed that, in addition to the NH3atmosphere-N doped into VO2lattice, the pyrrolidone-N introduced N-containing groups with N–N, N–O, or N–H bonds into the vicinity of the surface or void of the film in the form of molecular adsorption or atom (N, O, and H) filling. According to the Tauc plot, the estimated bandgap of N-incorporated VO2thin films related to metal-to-insulator transition (Eg1) was 0.16–0.26 eV, while that associated with the visible transparency (Eg2) was 1.31–1.45 eV. The calculatedEg1andEg2from the first-principles theory were 0.1–0.5 eV and 1.4–1.6 eV, respectively. The Tauc plot estimation and theoretical calculations suggested that the combined effect of N-doping and N-adsorption with the extra atom (H, N, and O) decreased the critical temperature (τc) due to the reduction inEg1.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
LANGMUIR
·
2010
·
IF 3.898
Zongtao Zhang,Yanfeng Gao,Zhang Chen,Jing Du,Chuanxiang Cao,Litao Kang,Hongjie Luo
This paper describes a solution-phase synthesis of high-quality vanadium dioxide thermochromic thin films. The films obtained showed excellent visible transparency and a large change in transmittance at near-infrared (NIR) wavelengths before and after the metal−insulator phase transition (MIPT). For a 59 nm thick single-layer VO2 thin film, the integral values of visible transmittance (Tint) for metallic (M) and semiconductive (S) states were 54.1% and 49.1%, respectively, while the NIR switching efficiencies (ΔT) were as high as 50% at 2000 nm. Thinner films can provide much higher transmittance of visible light, but they suffer from an attenuation of the switching efficiency in the near-infrared region. By varying the film thickness, ultrahigh Tint values of 75.2% and 75.7% for the M and S states, respectively, were obtained, while the ΔT at 2000 nm remained high. These results represent the best data for VO2 to date. Thicker films in an optimized range can give enhanced NIR switching efficiencies and excellent NIR blocking abilities; in a particularly impressive experiment, one film provided near-zero NIR transmittance in the switched state. The thickness-dependent performance suggests that VO2 will be of great use in the objective-specific applications. The reflectance and emissivity at the wavelength range of 2.5−25 μm before and after the MIPT were dependent on the film thickness; large contrasts were observed for relatively thick films. This work also showed that the MIPT temperature can be reduced simply by selecting the annealing temperature that induces local nonstoichiometry; a MIPT temperature as low as 42.7 °C was obtained by annealing the film at 440 °C. These properties (the high visible transmittance, the large change in infrared transmittance, and the near room-temperature MIPT) suggest that the current method is a landmark in the development of this interesting material toward applications in energy-saving smart windows.
研究领域:
材料科学
·
能源技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yuang Zhang,Rongwen Lu,Shufen Zhang,Bingtao Tang
Solar thermoelectric generation (STEG) is an excellent and environmentally-friendly way to convert thermal energy into electricity by utilizing Seebeck effect of thermoelectric material. However, how to overcome the rigidity and large output fluctuation of traditional STEG is the key to realize its large-scale application in self-powered devices. Herein, a smart light-driven flexible STEG system was designed and constructed through simple layered structure of VO 2 flexible film and carbon nanotube (CNT) thermoelectric modules. Based on the optical control characteristics of VO 2 flexible film due to the thermal crystal phase transformation, and the light capture, photo-thermal-electric conversion capabilities of CNT flexible film, the smart light-driven flexible STEG system exhibits good flexibility, light-thermal-electrical conversion and stable voltage output. In the above system, CNT, polyvinylidene fluoride (PVDF) as raw material and polyethyleneimine (PEI) as electron donor, p- and n-type flexible thermoelectric films and modules were constructed; VO 2 ultrafine powder was dispersed in polyvinylpyrrolidone (PVP), and the optical control VO 2 flexible film was obtained by simple spin coating on the flexible substrate. The system is so flexible that can be folded or bended to different shapes to adapt to different application environments. Furthermore, the intelligent light-driven flexible STEG system can obtain relatively stable voltage to prevent the damage of equipment caused by large voltage fluctuation and has great application potential in civil micro-self-powered devices.
研究领域:
材料科学
·
能源技术
✓ 已验证
DOI
高影响因子
Defence Technology
·
2025
·
IF 5.9
Yingke Chang,Pengtao Cheng,Zhe Kong,Jianxin Nie,Wei Ren,Xiaohui Liang,Enyi Chu,Qingjie Jiao,Jianjun Luo
Initiating explosive devices (IEDs) are crucial in both military and civilian applications for improving the accuracy of controlled detonations. However, the safety of semiconductor bridge (SCB) wire IEDs, which are the most widely used, is increasingly threatened by complex electromagnetic environments. Although protective devices such as thermistors and zener diodes are commonly employed to enhance safety, traditional discrete components can compromise compactness and provide only marginal improvements. The metal-insulator transition properties of vanadium dioxide (VO 2 ) present an innovative approach to enhancing the safety performance of IEDs. Nevertheless, the functional relevance of the VO 2 phase transition in relation to IEDs has garnered limited scientific attention. The VO 2 film fabricated via 3D printing demonstrated resistivity modulation ranging from 2 to 5 orders of magnitude, achieving a stable metallic-state resistance of 1.2 Ω. The results show that this process increases the 5-minute safe current threshold by 90%, from 1 A to 1.9 A, and reduces the temperature generated by the current by approximately 40% when below the safe current threshold. Integrating VO 2 film into IEDs via semiconductor processes significantly enhances safety performance while maintaining detonation capability, demonstrating its effectiveness as a safety modulator in pyrotechnic engineering.
研究领域:
材料科学
·
电气工程
·
增材制造
·
固体物理
·
烟火技术
·
安全工程
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）