scholarly journals High-Performance Humidity Sensor Based on the Graphene Flower/Zinc Oxide Composite

Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 242
Author(s):  
Muhammad Saqib ◽  
Shenawar Ali Khan ◽  
Hafiz Mohammad Mutee Ur Rehman ◽  
Yunsook Yang ◽  
Seongwan Kim ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
High Performance ◽  
Humidity Sensor ◽  
Electronic Device ◽  
Sol Gel ◽  
Functional Materials ◽  
Cost Effective ◽  
Functional Material ◽  
Functional Layer ◽  
Highly Sensitive

Performance of an electronic device relies heavily on the availability of a suitable functional material. One of the simple, easy, and cost-effective ways to obtain novel functional materials with improved properties for desired applications is to make composites of selected materials. In this work, a novel composite of transparent n-type zinc oxide (ZnO) with a wide bandgap and a unique structure of graphene in the form of a graphene flower (GrF) is synthesized and used as the functional layer of a humidity sensor. The (GrF/ZnO) composite was synthesized by a simple sol–gel method. Morphological, elemental, and structural characterizations of GrF/ZnO composite were performed by a field emission scanning electron microscope (FESEM), energy-dispersive spectroscopy (EDS), and an x-ray diffractometer (XRD), respectively, to fully understand the properties of this newly synthesized functional material. The proposed humidity sensor was tested in the relative humidity (RH) range of 15% RH% to 86% RH%. The demonstrated sensor illustrated a highly sensitive response to humidity with an average current change of 7.77 μA/RH%. Other prominent characteristics shown by this device include but were not limited to high stability, repeatable results, fast response, and quick recovery time. The proposed humidity sensor was highly sensitive to human breathing, thus making it a promising candidate for various applications related to health monitoring.

scholarly journals Elucidation of the Crystal Growth Characteristics of SnO2 Nanoaggregates Formed by Sequential Low-Temperature Sol-Gel Reaction and Freeze Drying

Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1738
Author(s):  
Saeid Vafaei ◽  
Alexander Wolosz ◽  
Catlin Ethridge ◽  
Udo Schnupf ◽  
Nagisa Hattori ◽  
...  
Keyword(s):  
Crystal Growth ◽  
Low Temperature ◽  
Photoelectron Spectroscopy ◽  
High Performance ◽  
Freeze Drying ◽  
Sno2 Nanoparticles ◽  
Sol Gel ◽  
Functional Materials ◽  
Cost Effective ◽  
High Concentration

SnO2 nanoparticles are regarded as attractive, functional materials because of their versatile applications. SnO2 nanoaggregates with single-nanometer-scale lumpy surfaces provide opportunities to enhance hetero-material interfacial areas, leading to the performance improvement of materials and devices. For the first time, we demonstrate that SnO2 nanoaggregates with oxygen vacancies can be produced by a simple, low-temperature sol-gel approach combined with freeze-drying. We characterize the initiation of the low-temperature crystal growth of the obtained SnO2 nanoaggregates using high-resolution transmission electron microscopy (HRTEM). The results indicate that Sn (II) hydroxide precursors are converted into submicrometer-scale nanoaggregates consisting of uniform SnO2 spherical nanocrystals (2~5 nm in size). As the sol-gel reaction time increases, further crystallization is observed through the neighboring particles in a confined part of the aggregates, while the specific surface areas of the SnO2 samples increase concomitantly. In addition, X-ray photoelectron spectroscopy (XPS) measurements suggest that Sn (II) ions exist in the SnO2 samples when the reactions are stopped after a short time or when a relatively high concentration of Sn (II) is involved in the corresponding sol-gel reactions. Understanding this low-temperature growth of 3D SnO2 will provide new avenues for developing and producing high-performance, photofunctional nanomaterials via a cost-effective and scalable method.

Synthesized of Highly Sensitive Tin (IV)-Doped Zinc Oxide Humidity Sensor

2015 ◽  
Vol 1109 ◽  
pp. 559-563
Author(s):  
Ahmad Syakirin Ismail ◽  
Mohd Firdaus Malek ◽  
Muhammad Amir Ridhwan Abdullah ◽  
Mohamad Hafiz Mamat ◽  
M. Rusop
Keyword(s):  
Zinc Oxide ◽  
Recovery Time ◽  
Humidity Sensor ◽  
Sol Gel ◽  
High Sensitivity ◽  
Average Diameter ◽  
Undoped Sample ◽  
Immersion Method ◽  
Response Recovery ◽  
Highly Sensitive

High sensitivity Tin (IV) (Sn) - doped zinc oxide (ZnO) humidity sensor was deposited using sol-gel immersion method. The Sn-doped sample was deposited on glass substrate and undoped sample was also prepared to seem the improvement made through doping process. The analyses showed that the sensor’s morphology has become more porous and having lower average diameter of nanorods, high conductivity and higher response, recovery time, and sensitivity. The sensitivity of the sensor increased from 2 to 4 by doping with Sn.

scholarly journals Mode Sensitivity Exploration of Silica–Titania Waveguide for Refractive Index Sensing Applications

Sensors ◽  
2021 ◽  
Vol 21 (22) ◽  
pp. 7452
Author(s):  
Muhammad A. Butt ◽  
Andrzej Kaźmierczak ◽  
Cuma Tyszkiewicz ◽  
Paweł Karasiński ◽  
Ryszard Piramidowicz
Keyword(s):  
Refractive Index ◽  
High Performance ◽  
Near Infrared ◽  
Sol Gel ◽  
Cost Effective ◽  
Dip Coating ◽  
Infrared Wavelength ◽  
Refractive Index Sensing ◽  
Sensing Applications ◽  
Coating Method

In this paper, a novel and cost-effective photonic platform based on silica–titania material is discussed. The silica–titania thin films were grown utilizing the sol–gel dip-coating method and characterized with the help of the prism-insertion technique. Afterwards, the mode sensitivity analysis of the silica–titania ridge waveguide is investigated via the finite element method. Silica–titania waveguide systems are highly attractive due to their ease of development, low fabrication cost, low propagation losses and operation in both visible and near-infrared wavelength ranges. Finally, a ring resonator (RR) sensor device was modelled for refractive index sensing applications, offering a sensitivity of 230 nm/RIU, a figure of merit (FOM) of 418.2 RIU−1, and Q-factor of 2247.5 at the improved geometric parameters. We believe that the abovementioned integrated photonics platform is highly suitable for high-performance and economically reasonable optical sensing devices.

Nanostructured Zinc Oxide Thin Film Based Humidity Sensor Prepared by Sol-Gel Immersion Technique

2013 ◽  
Vol 667 ◽  
pp. 553-557 ◽  
Author(s):  
M. Awalludin ◽  
Mohamad Hafiz Mamat ◽  
Mohd Zainizan Sahdan ◽  
Z. Mohamad ◽  
Mohamad Rusop
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Immersion Time ◽  
Humidity Sensor ◽  
Sol Gel ◽  
Oxide Thin Film ◽  
Nanostructured Zinc Oxide ◽  
Time Scanning ◽  
Immersion Technique ◽  
Intensity Increment

This paper focus on nanostructured Zinc Oxide (ZnO) thin film based humidity sensor prepared using sol-gel method immersion technique at different immersion time. Scanning Electron Microscopy (SEM) investigations reveal nanorods ZnO were deposited on glass substrate with nanorods length increased with immersion time. All fabricated sensors show current intensity increment response when relative humidity is increased. Sensor fabricated at 16 hr immersion time shows the highest sensitivity in this study.

Humidity Sensor - A Review of Nanostructured Zinc Oxide (ZnO)-Based Humidity Sensor

2015 ◽  
Vol 1109 ◽  
pp. 395-400 ◽  
Author(s):  
A.S. Ismail ◽  
M.H. Mamat ◽  
Mohamad Rusop
Keyword(s):  
Zinc Oxide ◽  
Band Gap ◽  
Humidity Sensor ◽  
Preparation Method ◽  
Low Cost ◽  
Sol Gel ◽  
Extreme Environment ◽  
Humidity Sensors ◽  
Humidity Sensing ◽  
Gel Preparation

We have reviewed humidity sensors based on the Zinc oxide (ZnO) humidity sensor. There are only a few papers reviewing on the ZnO humidity sensor. The characteristics, structures, advantages, and fabrication methods of ZnO have been studied to understand the suitability of the ZnO to be applied at different kind of condition such as for extreme environment, low level humidity detection, and very high humidity level circumstances. The electrical and physical properties of ZnO humidity sensors such as sensitivity, response time, stability, uniformity, and crystallinity have also been discussed in this review. ZnO nanostructures have been widely used for humidity sensors because of its’ good stability, high sensitivity for humidity-sensing, low cost, and has a wide band gap. Sol-gel preparation method is commonly used to for ZnO humidity sensor fabrication since it can produce a film with high uniformity, simple process and low cost. Keywords: Humidity Sensor, Metal Oxide, Semiconducting Type, Ceramic Type, Humidity-Sensing, Band Gap, Sol-Gel Preparation Method.

scholarly journals Effect of Precursors on Structural and Optical Properties of Sol-Gel Synthesized ZnO Nanopowders

2019 ◽  
Vol 31 (8) ◽  
pp. 1825-1829
Author(s):  
A. Vanaja ◽  
Jaison Jeevanandam ◽  
M. Suresh
Keyword(s):  
Zinc Oxide ◽  
Optical Properties ◽  
Optical Absorption ◽  
Sol Gel ◽  
Cost Effective ◽  
Optoelectronic Device ◽  
Zinc Nitrate ◽  
X Ray Diffraction ◽  
Absorption And Emission ◽  
Device Applications

The present work aims at evaluating the outcome of zinc precursors on the crystal structure, shape, surface and optical properties of ZnO nanopowders. Zinc oxide nanopowders are fabricated via simple, cost-effective, low-temperature, the sol-gel method using different zinc precursors such as zinc nitrate and zinc chloride. The structural properties of the obtained ZnO nanopowders are studied using X-ray diffraction spectra and their morphology from SEM micrographs. Further, Fourier transform infrared spectra reveals the existence of functional groups that supports the formation of zinc oxide. Moreover, optical absorption and emission of ZnO nanopowders were evaluate during ultraviolet-visible and photoluminescence spectra. The results of this study revealed that the precursor is significant in altering the crystallite size, shape, optical absorption and emission entities of nanopowders. In addition, the role of zinc precursors to fabricate nanopowders that is suitable for various optoelectronic device applications were also discussed.

Investigate the Reliable and Accurate Pattern Transfer of IDE Silver Electrode Coated with Zinc Oxide Microwire for Biosensor Application

2014 ◽  
Vol 925 ◽  
pp. 529-532
Author(s):  
R. Haarindra Prasad ◽  
Kai Long Foo ◽  
U. Hashim
Keyword(s):  
Zinc Oxide ◽  
Electronic Device ◽  
Uv Light ◽  
Sol Gel ◽  
Electrical Characterization ◽  
Pattern Transfer ◽  
Zno Films ◽  
Oxide Material ◽  
Chemical Route ◽  
Biosensor Application

This paper illustrate a facile route to fabricate and develop zinc oxide microwire which acts as transducer for biosensor application. Pattern transfer process is conducted on the wafer substrate by using conventional photolithography process to form IDE electrode. The substrate is coated with positive photo-resist (PR) and exposed for UV light for 10 seconds. After development, the unexposed area is etched by using hydrochloric acid, HCI. In this study, zinc oxide material have become a remarkable choice for bio-sensing development due to large band gap and tailor for bio-molecular application. Zinc oxide solution was prepared through chemical route, that is by using sol-gel method. The coated ZnO films were annealed in furnace at 500°C for 2 hours. ZnO seed solution undergoes hydrothermal growth to synthesize ZnO microwires. ithThe substrate used for this study is p-type silicon wafer which is oxidized. SiO2 layer is used because it acts as an insulator which is very essential for an electronic device to avoid electrical leakage and improve electron mobility. Further investigation of morphological and electrical characterization is conducted through SEM and I-V test .Average size diameter of Zno microwire is 0.45μm and exhibit 900μA of current at 5V.

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