| 1. |
- Batool, S S., et al.
(författare)
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Comparative Analysis of Ti, Ni, and Au Electrodes on Characteristics of TiO2 Nanofibers for Humidity Sensor Application
- 2013
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Ingår i: Journal of Materials Science & Technology. - : Elsevier. - 1005-0302. ; 29:5, s. 411-414
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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.
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| 2. |
- Batool, S S., et al.
(författare)
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Investigation of dielectric relaxation behavior of electrospun titanium dioxide nanofibers using temperature dependent impedance spectroscopy
- 2013
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:2, s. 1775-1783
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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.
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| 3. |
- Batool, S S, et al.
(författare)
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Silica nanofibers based impedance type humidity detector prepared on glass substrate
- 2013
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Ingår i: Vacuum. - : Elsevier. - 0042-207X .- 1879-2715. ; 87, s. 1-6
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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.
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| 4. |
- Imran, Z., et al.
(författare)
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Excellent humidity sensing properties of cadmium titanate nanofibers
- 2013
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 39:1, s. 457-462
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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.
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| 5. |
- Imran, Z, et al.
(författare)
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Fabrication of cadmium titanate nanofibers via electrospinning technique
- 2012
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 38:4, s. 3361-3365
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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.
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| 6. |
- Jamil, Hira, et al.
(författare)
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Electrospun titanium dioxide nanofiber humidity sensors with high sensitivity
- 2012
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Ingår i: Ceramics International. - : Elsevier. - 0272-8842 .- 1873-3956. ; 38:3, s. 2437-2441
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Tidskriftsartikel (refereegranskat)abstract
- Titanium dioxide nanofibers were synthesized using electrospinning technique. The nanofibers were porous with an average diameter and length of similar to 150 nm and 200 p,m, respectively. Humidity-sensing devices were fabricated by lithographically defined aluminum electrodes on top of the nanofibers deposited on silicon dioxide grown thermally on a silicon substrate. The performance of a TiO2 nanofiber humidity sensor was tested by AC and DC electrical measurements at 40-90% relative humidity. The response and the recovery time were 1 s and 4 s, respectively, between 40% and 90% relative humidity. The sensitivity of the TiO2 humidity sensor in the range of 40-90% RH was 150 M Omega/%RH and 20 M Omega/%RH at 10 Hz and 100 Hz, respectively. The excellent sensing characteristics are attributed to the porous nature and the small diameter of the nanofibers.
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| 7. |
- Rafiq, Iqra, et al.
(författare)
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IoT applications and challenges in smart cities and services
- 2023
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Ingår i: The Journal of Engineering. - : John Wiley & Sons. - 2051-3305. ; 2023:4
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Forskningsöversikt (refereegranskat)abstract
- Internet of Things (IoT) is a revolutionary and novel platform where a smart network connects to the large number of electronic devices via internet through available communication systems for reliable and real time connectivity, sensing thus acquiring data from sensors, computing and actuating devices. A review of the current status of IoT features, architecture, communication infrastructure and applications is presented here. Number of IoT applications and challenges in the development of smart cities are covered about this innovative technological platform in this review along with communication protocols characteristics and applications. IoT aided smart city services, health applications, transport applications and smart grid improvements are also discussed. Many challenges and issues related to security, communication, applications and system architecture along with future directions of IoT technology are elaborated in detail.
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| 8. |
- Ullah, Zahid, et al.
(författare)
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Natural fibers and zinc hydroxystannate 3D microspheres based composite paper sheets for modern bendable energy storage application
- 2023
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Ingår i: Journal of Applied Polymer Science. - : John Wiley & Sons. - 0021-8995 .- 1097-4628. ; 140:1
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Tidskriftsartikel (refereegranskat)abstract
- For modern high-tech flexible energy storage devices, it becomes important to synthesize micro-/nanostructures as per the required shape and morphology with superior physical and electro-active characteristics. This work shares the fabrication and characterization of ZnSn(OH)(6) (Zinc hydroxystannate [ZHS]) prepared by facile microwave-assisted technique and furthermore converted into flexible sheets by employing lignocelluloses (LC) known as natural fibers, collected from Carica papaya leaf petiole as a substrate to provide the flexible matrix. X-ray diffraction measurements confirm the successful crystalline structure of ZHS. Scanning electron microscopy and transmission electron microscopy showed the solid spherical structure of ZHS microspheres. Fourier transform infrared spectrometry and Raman spectroscopy confirmed the composite formation of ZHS and LC-based composite sheets (ZHS/LC sheets). Electrochemical measurements that is, cyclic voltammetry (CV), Galvanostatic charge/discharge, and electrochemical impedance (EIS) spectroscopy revealed the electroactive behavior of ZHS/LC paper sheets as working electrode for energy storage applications. CV measurements revealed the specific capacitance of 100 F/g and EIS measurements confirmed the decrease in the resistance of LC fiber after the growth of ZHS microspheres. Presented flexible ZHS based paper sheets will be highly feasible for the modern bendable/flexible/disposable energy storage applications.
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