| 1. |
- Imran, Z., et al.
(författare)
-
Excellent humidity sensing properties of cadmium titanate nanofibers
- 2013
-
Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:1, s. 457-462
-
Tidskriftsartikel (refereegranskat)abstract
- We report humidity sensing characteristics of CdTiO3 nanofibers prepared by electrospinning. The nanofibers were porous having an average diameter and length of similar to 50-200 nm and similar to 100 mu m, respectively. The nanofiber humidity sensor was fabricated by defining aluminum electrodes using photolithography on top of the nanofibers deposited on glass substrate. The performance of the CdTiO3 nanofiber humidity sensor was evaluated by AC electrical characterization from 40% to 90% relative humidity at 25 degrees C. The frequency of the AC signal was varied from 10(-1) to 10(6) Hz. Fast response time and recovery time of 4 s and 6 s were observed, respectively. The sensor was highly sensitive and exhibited a reversible response with small hysteresis of less than 7%. Long term stability of the sensor was confirmed during 30 day test. The excellent sensing characteristics prove that the CdTiO3 nanofibers are potential candidate for use in high performance humidity sensors.
|
|
| 2. |
- Batool, S S., et al.
(författare)
-
Comparative Analysis of Ti, Ni, and Au Electrodes on Characteristics of TiO2 Nanofibers for Humidity Sensor Application
- 2013
-
Ingår i: Journal of Materials Science & Technology. - : Elsevier. - 1005-0302. ; 29:5, s. 411-414
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of metal (Ti, Ni, and Au) electrodes on humidity sensing properties of electrospun TiO2 nanofibers was investigated in this work. The devices were fabricated by evaporating metal contacts on SiO2 layer thermally grown on silicon substrate. The separation between the electrodes was 90 mm for all sensors. The sensors were tested from 40% to 90% relative humidity (RH) by AC electrical characterization at room temperature. When sensors are switched between 40% and 90% RH, the corresponding response and recovery time are 3 s and 5 s for Ti-electrode sensor, 4 s and 7 s for Ni-electrode sensor, and 7 s and 13 s for Au-electrode sensor. The hysteresis was 3%, 5% and 15% for Ti-, Ni-, and Au-electrode sensor, respectively. The sensitivity of Ti, Ni, and Au-electrode sensors are 7.53 M Omega/% RH, 5.29 MU/% RH and 4.01 M Omega/% RH respectively at 100 Hz. Therefore Ti-electrode sensor is found to have linear response, fast response and recovery time and higher sensitivity as compared with those of Ni- and Au-electrode sensors. Comparison of humidity sensing properties of sensors with different electrode material may propose a compelling route for designing and optimizing humidity sensors.
|
|
| 3. |
- Batool, S S., et al.
(författare)
-
Investigation of dielectric relaxation behavior of electrospun titanium dioxide nanofibers using temperature dependent impedance spectroscopy
- 2013
-
Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:2, s. 1775-1783
-
Tidskriftsartikel (refereegranskat)abstract
- The electrospinning method has been utilized in the fabrication of titanium dioxide nanofibers (TNFs) with an average diameter of similar to 50 nm and length of 100 um. Effect of temperature on the dielectric relaxation behavior of the fabricated nanofibers have been studied using AC impedance spectroscopy. The morphological, structural and compositional aspects as well as the optical properties of the TNFs have been investigated by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), energy-dispersive x-ray spectroscopy (EDX) and ultraviolet visible (UV vis) absorption spectrum. The permittivity behavior of the device at the frequency below 10(2) Hz shows the relaxation contribution along with the electrode polarization. Dielectric loss peak in loss tangent also confirms the presence of relaxing dipoles in TNFs. The AC conductance as a function of frequency confirms the semiconducting nature of TNFs and obeys Jonschers power law except a small deviation in the low frequency region. DC conductivity increases with increase in temperature.
|
|
| 4. |
- Batool, S S, et al.
(författare)
-
Silica nanofibers based impedance type humidity detector prepared on glass substrate
- 2013
-
Ingår i: Vacuum. - : Elsevier. - 0042-207X .- 1879-2715. ; 87, s. 1-6
-
Tidskriftsartikel (refereegranskat)abstract
- Impedance type relative humidity detector is fabricated by depositing electrospun silica nanofibers on glass substrate. The silica nanofibers with an average diameter similar to 150 nm and length similar to 100 mu m were used. Thermogravimetric and differential scanning calorimetric analysis confirm that the accurate annealing temperature is 500 degrees C for complete removal of PVP. Humidity detecting devices were fabricated by defining titanium electrodes on top of the silica nanofibers. The performance of silica nanofibers humidity detectors was tested by AC electrical measurements at 40-90% relative humidity. The response and the recovery times were 5 s and 3 s, respectively, between 40% and 90% relative humidity. Contribution of dipoles, space charge polarization, relaxation of these dipoles and low frequency dispersion phenomenon were observed during impedance measurements.
|
|
| 5. |
- Imran, Z, et al.
(författare)
-
Fabrication of cadmium titanate nanofibers via electrospinning technique
- 2012
-
Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 38:4, s. 3361-3365
-
Tidskriftsartikel (refereegranskat)abstract
- Here we present an electrospinning technique for the fabrication of cadmium titanate/polyvinyl-pyrrolidone composite nanofibers. The composite nanofibers are then annealed at 600 degrees C to obtain ilmenite rhombohedral phase cadmium titanate nanofibers. The structure, composition, thermal stability and optical properties of as synthesized and annealed cadmium titanate nanofibers are characterized by X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis, Fourier transform infrared spectroscopy and ultraviolet-visible spectroscopy. The average diameter and length of the nanofibers are found to be similar to 150-200 nm and similar to 100 mu m, respectively.
|
|
