scholarly journals The Effect of Alkali Metal (Na, K) Doping on Thermochromic Properties of VO2 Films

MRS Advances ◽  
2018 ◽  
Vol 3 (32) ◽  
pp. 1863-1869 ◽  
Author(s):  
Işıl Top ◽  
Johannes Schläfer ◽  
Russell Binions ◽  
Ioannis Papakonstantinou ◽  
Sriluxmi Srimurugananthan ◽  
...  
Keyword(s):  
Transition Temperature ◽  
Alkali Metal ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Critical Transition Temperature ◽  
Low Temperature Annealing ◽  
Thermochromic Properties ◽  
Metal Doped ◽  
Sodium And Potassium ◽  
Vanadium Dioxide Thin Films

ABSTRACT:This work reports the synthesis of undoped and alkali metal doped thermochromic vanadium dioxide thin films by sol-gel spin coating and subsequent low-temperature annealing at 450 °C in N2-H2 atmosphere. The effect of sodium and potassium on the phase transition temperature as well as on the solar modulations were investigated. A dopant concentration of 0.3 at% resulted in a reduction of the critical transition temperature (Tc) from 62 °C to 57 °C and 47 °C for the sodium and potassium doped films, respectively. Moreover, both dopants improved the solar modulations (ΔTsol) of the undoped VO2 films from 3.81 to 9.44 and 5.43 %, respectively.

Study on the Grain Size of Vanadium Dioxide Thin Films using Sol-gel Spin Coating Method

2018 ◽  
Author(s):  
Ibrahim Mohd Yazid ◽  
Muhammad Hazim Raselan ◽  
Shafinaz Sobihana Shariffudin ◽  
Puteri Sarah Mohamad Saad ◽  
Sukreen Hana ◽  
...  
Keyword(s):  
Thin Films ◽  
Grain Size ◽  
Vanadium Dioxide ◽  
Spin Coating ◽  
Sol Gel ◽  
Spin Coating Method ◽  
Coating Method ◽  
Vanadium Dioxide Thin Films

scholarly journals Mg/W-codoped vanadium dioxide thin films with enhanced visible transmittance and low phase transition temperature

2015 ◽  
Vol 3 (26) ◽  
pp. 6771-6777 ◽  
Author(s):  
Ning Wang ◽  
Shiyu Liu ◽  
X. T. Zeng ◽  
Shlomo Magdassi ◽  
Yi Long
Keyword(s):  
Thin Films ◽  
Phase Transition ◽  
Transition Temperature ◽  
Charge Carrier ◽  
Band Gap ◽  
Phase Transition Temperature ◽  
Vanadium Dioxide ◽  
Visible Transmittance ◽  
Vanadium Dioxide Thin Films

Mg2+ and W6+ cations were first codoped into the VO2 lattice, resulting in a widened photon band gap and h+/e− charge carrier accumulation. These effects enhanced the thermochromic performance with a high visible transmission (∼80%) and a low phase transition temperature (∼30 °C).

Optical Switches Based on Vanadium Dioxide Films Grown By The Sol-Gel Process

1990 ◽  
Vol 180 ◽  
Author(s):  
Richard S. Potember ◽  
Kenneth R. Speck
Keyword(s):  
Transition Metal Oxides ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Optical Switches ◽  
Glass Slides ◽  
Sol Gel Process ◽  
Metal Phase Transition ◽  
Isopropanol Solution ◽  
High Degree ◽  
Vanadium Dioxide Thin Films

ABSTRACTVanadium dioxide thin films have been grown from vanadium tetrakis (t-butoxide) by the sol-gel process. A new method for the synthesis of the vanadium precursor was also developed. Films were deposited by dipcoating glass slides from an isopropanol solution, followed by post-deposition annealing of the films at 600°C under nitrogen. The properties of these films, to a high degree, were a function of crystalline boundaries and crystalline grain size. These gel-derived VO2 films undergo a reversible semiconductor-to-metal phase transition near 72°C, exhibiting characteristic resistive and spectral switching comparable with near stoichiometric VO2 films prepared on non-crystalline substrates by other techniques. Films were doped with hexavalent transition metal oxides to demonstrate lowering of the transition of the transition temperature.

Structure of Alkali Metal-Catalyzed Butadiene Polymers

1953 ◽  
Vol 26 (3) ◽  
pp. 522-527
Author(s):  
A. W. Meyer ◽  
R. R. Hampton ◽  
J. A. Davison
Keyword(s):  
Transition Temperature ◽  
Alkali Metal ◽  
Infrared Absorption ◽  
Styrene Copolymers ◽  
A Value ◽  
Second Order Transition ◽  
Metal Catalyzed ◽  
Sodium And Potassium ◽  
Absorption Measurements ◽  
Butadiene Styrene

Abstract The structures of various sodium and potassium-catalyzed butadiene polymers were determined from infrared absorption measurements. All of the polymers had a higher proportion of butadiene in the 1,2-configuration (45–80 per cent) than emulsion polybutadiene (18–23 per cent). Polybutadienes catalyzed by potassium had 15–20 per cent less butadiene in the 1,2-configuration than those in which sodium was the catalyst. When a mixture of sodium and potassium was used, the results were nearly the same as with the potassium catalyst alone. Polybutadienes made at 5° had 10 to 15 per cent more butadiene in the 1,2-configuration than those made at 45°. Diluent type had little or no effect on the structure of the polybutadienes. The butadiene portions of butadiene-styrene copolymers were found to have the same relative proportions of 1,2-, cis-1,4- and trans-1,4-configurations as the butadiene homopolymers. The second order transition temperature of sodium-catalyzed polybutadiene polymerized at 30° was −45°, whereas the 75° polybutadiene had a value of −64°.

Vanadium Dioxide Films Grown from Vanadium Tetrakis(t-Butoxide) by the Sol-Gel Process

1988 ◽  
Vol 121 ◽  
Author(s):  
K. R. Speck ◽  
H. S-W. Hu ◽  
R. A. Murphy ◽  
R. S. Potember
Keyword(s):  
Transition Metal Oxides ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Preparation Conditions ◽  
Glass Slides ◽  
Sol Gel Process ◽  
Metal Phase Transition ◽  
Isopropanol Solution ◽  
High Degree ◽  
Vanadium Dioxide Thin Films

ABSTRACTVanadium dioxide thin films have been grown from vanadium tetrakis (t-butoxide) by the sol-gel process. A new method for the synthesis of the vanadium precursor was developed. Films were deposited by dipcoating glass slides from an isopropanol solution, followed by post-deposition annealing of the films at 600 °C under nitrogen. The properties of these films, to a high degree, were a function of the preparation conditions. These gel-derived VO2 films undergo a reversible semiconductor-to-metal phase transition near 72 °C, exhibiting characteristic resistive and spectral switching comparable with near stoichiometric VO2 films prepared on non-crystalline substrates by other techniques. Paralleling the investigation of pure VO2, films were doped with hexavalent transition metal oxides to demonstrate lowering of the transition temperature.

Thermochromic characteristics of WO3-doped vanadium dioxide thin films prepared by sol–gel method

2012 ◽  
Vol 38 ◽  
pp. S589-S593 ◽  
Author(s):  
Jeong-Ho Cho ◽  
Young-Jun Byun ◽  
Jin-Ho Kim ◽  
Young-Jin Lee ◽  
Young-Hun Jeong ◽  
...  
Keyword(s):  
Thin Films ◽  
Vanadium Dioxide ◽  
Sol Gel ◽  
Gel Method ◽  
Sol Gel Method ◽  
Vanadium Dioxide Thin Films
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