Metal-to-insulator transition near room temperature in graphene oxide and graphene oxide + TiO2 thin films

RSC Advances ◽  
2016 ◽  
Vol 6 (114) ◽  
pp. 112864-112869 ◽  
Author(s):  
G. H. Wegher ◽  
E. R. Viana ◽  
G. M. Ribeiro ◽  
J. F. Deus
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Titanium Oxide ◽  
Room Temperature ◽  
Insulator Transition ◽  
Tio2 Thin Films ◽  
Chemical Route ◽  
Metal To Insulator Transition

Thin films of graphene oxide and a composite of graphene oxide with titanium oxide were prepared via an alternative chemical route based on Hummer's method. Metal-to-Insulator Transition (MIT) were observed for GO (at 280 K) and for GO + TiO2 (at 260 K).

A chemical route to room-temperature synthesis of nanocrystalline TiO2 thin films

2005 ◽  
Vol 246 (1-3) ◽  
pp. 72-76 ◽  
Author(s):  
Habib M. Pathan ◽  
Woo Young Kim ◽  
Kwang-Deog Jung ◽  
Oh-Shim Joo
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Tio2 Thin Films ◽  
Temperature Synthesis ◽  
Nanocrystalline Tio2 ◽  
Chemical Route ◽  
Room Temperature Synthesis

scholarly journals Metal-to-insulator transition in anatase TiO2 thin films induced by growth rate modulation

2012 ◽  
Vol 101 (2) ◽  
pp. 022104 ◽  
Author(s):  
T. Tachikawa ◽  
M. Minohara ◽  
Y. Nakanishi ◽  
Y. Hikita ◽  
M. Yoshita ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Anatase Tio2 ◽  
Insulator Transition ◽  
Tio2 Thin Films ◽  
Rate Modulation ◽  
Metal To Insulator Transition

Investigation of the metal-to-insulator transition of N-doped VO2(M1) thin films

2021 ◽  
pp. 149661
Author(s):  
Simon Chouteau ◽  
Sabeur Mansouri ◽  
Mohamed Lemine Ould Ne Mohamedou ◽  
Jérémie Chaillou ◽  
Aminat Oyiza Suleiman ◽  
...  
Keyword(s):  
Thin Films ◽  
Insulator Transition ◽  
Metal To Insulator Transition

scholarly journals Functionalized Reduced Graphene Oxide Thin Films for Ultrahigh CO2 Gas Sensing Performance at Room Temperature

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 623
Author(s):  
Monika Gupta ◽  
Huzein Fahmi Hawari ◽  
Pradeep Kumar ◽  
Zainal Arif Burhanudin ◽  
Nelson Tansu
Keyword(s):  
Thin Films ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Gas Sensor ◽  
Functional Groups ◽  
Recovery Time ◽  
Room Temperature ◽  
Co2 Gas ◽  
Reduced Graphene ◽  
Response And Recovery

The demand for carbon dioxide (CO2) gas detection is increasing nowadays. However, its fast detection at room temperature (RT) is a major challenge. Graphene is found to be the most promising sensing material for RT detection, owing to its high surface area and electrical conductivity. In this work, we report a highly edge functionalized chemically synthesized reduced graphene oxide (rGO) thin films to achieve fast sensing response for CO2 gas at room temperature. The high amount of edge functional groups is prominent for the sorption of CO2 molecules. Initially, rGO is synthesized by reduction of GO using ascorbic acid (AA) as a reducing agent. Three different concentrations of rGO are prepared using three AA concentrations (25, 50, and 100 mg) to optimize the material properties such as functional groups and conductivity. Thin films of three different AA reduced rGO suspensions (AArGO25, AArGO50, AArGO100) are developed and later analyzed using standard FTIR, XRD, Raman, XPS, TEM, SEM, and four-point probe measurement techniques. We find that the highest edge functionality is achieved by the AArGO25 sample with a conductivity of ~1389 S/cm. The functionalized AArGO25 gas sensor shows recordable high sensing properties (response and recovery time) with good repeatability for CO2 at room temperature at 500 ppm and 50 ppm. Short response and recovery time of ~26 s and ~10 s, respectively, are achieved for 500 ppm CO2 gas with the sensitivity of ~50 Hz/µg. We believe that a highly functionalized AArGO CO2 gas sensor could be applicable for enhanced oil recovery, industrial and domestic safety applications.

Irradiation induced ferromagnetism at room temperature in TiO2 thin films: X-ray magnetic circular dichroism characterizations

2011 ◽  
Vol 98 (19) ◽  
pp. 192512 ◽  
Author(s):  
Hardeep Thakur ◽  
P. Thakur ◽  
Ravi Kumar ◽  
N. B. Brookes ◽  
K. K. Sharma ◽  
...  
Keyword(s):  
Thin Films ◽  
Circular Dichroism ◽  
Room Temperature ◽  
Magnetic Circular Dichroism ◽  
Tio2 Thin Films ◽  
X Ray ◽  
Circular Dichroïsm

scholarly journals Metal–insulator-transition engineering by modulation tilt-control in perovskite nickelates for room temperature optical switching

2018 ◽  
Vol 115 (38) ◽  
pp. 9515-9520 ◽  
Author(s):  
Zhaoliang Liao ◽  
Nicolas Gauquelin ◽  
Robert J. Green ◽  
Knut Müller-Caspary ◽  
Ivan Lobato ◽  
...  
Keyword(s):  
Thin Films ◽  
Optical Switching ◽  
Room Temperature ◽  
Target Material ◽  
Insulator Transition ◽  
Fine Tuning ◽  
Perovskite Oxide ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Bond Angles

In transition metal perovskites ABO3, the physical properties are largely driven by the rotations of the BO6 octahedra, which can be tuned in thin films through strain and dimensionality control. However, both approaches have fundamental and practical limitations due to discrete and indirect variations in bond angles, bond lengths, and film symmetry by using commercially available substrates. Here, we introduce modulation tilt control as an approach to tune the ground state of perovskite oxide thin films by acting explicitly on the oxygen octahedra rotation modes—that is, directly on the bond angles. By intercalating the prototype SmNiO3 target material with a tilt-control layer, we cause the system to change the natural amplitude of a given rotation mode without affecting the interactions. In contrast to strain and dimensionality engineering, our method enables a continuous fine-tuning of the materials’ properties. This is achieved through two independent adjustable parameters: the nature of the tilt-control material (through its symmetry, elastic constants, and oxygen rotation angles), and the relative thicknesses of the target and tilt-control materials. As a result, a magnetic and electronic phase diagram can be obtained, normally only accessible by A-site element substitution, within the single SmNiO3 compound. With this unique approach, we successfully adjusted the metal–insulator transition (MIT) to room temperature to fulfill the desired conditions for optical switching applications.

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