scholarly journals Comparative Study on the Effect of Protonation Control for Resistive Gas Sensor Based on Close-Packed Polypyrrole Nanoparticles

2020 ◽  
Vol 10 (5) ◽  
pp. 1850 ◽  
Author(s):  
Wooyoung Kim ◽  
Sunghun Cho ◽  
Jun Seop Lee
Keyword(s):  
Conducting Polymer ◽  
High Sensitivity ◽  
Active Surface ◽  
Chain Structure ◽  
Polymer Chains ◽  
Active Surface Area ◽  
Recovery Times ◽  
Response And Recovery ◽  
Polypyrrole Nanoparticles ◽  
Sensor Transducer

Conducting polymers are often used as sensor electrodes due to their conjugated chain structure, which leads to high sensitivity and rapid response at room temperature. Numerous studies have been conducted on the structures of conducting polymer nanomaterials to increase the active surface area for the target materials. However, studies on the control of the chemical state of conducting polymer chains and the modification of the sensing signal transfer with these changes have not been reported. In this work, polypyrrole nanoparticles (PPyNPs), where is PPy is a conducting polymer, are applied as a sensor transducer to analyze the chemical sensing ability of the electrode. In particular, the protonation of PPy is adjusted by chemical methods to modify the transfer sensing signals with changes in the polymer chain structure. The PPyNPs that were modified at pH 1 exhibit high sensitivity to the target analyte (down to 1 ppb of NH3) with short response and recovery times of less than 20 s and 50 s, respectively, at 25 °C.

scholarly journals Gas-sensing features of nanostructured tellurium thin films

2020 ◽  
Vol 11 ◽  
pp. 1010-1018
Author(s):  
Dumitru Tsiulyanu
Keyword(s):  
Thin Films ◽  
Gas Sensing ◽  
Operating Temperature ◽  
Active Surface ◽  
Active Surface Area ◽  
Gas Sensitivity ◽  
Nanocrystalline And Amorphous ◽  
Recovery Times ◽  
Order Of Magnitude ◽  
Response And Recovery

Nanocrystalline and amorphous nanostructured tellurium (Te) thin films were grown and their gas-sensing properties were investigated at different operating temperatures with respect to scanning electron microscopy and X-ray diffraction analyses. It was shown that both types of films interacted with nitrogen dioxide, which resulted in a decrease of electrical conductivity. The gas sensitivity, as well as the response and recovery times, differed between these two nanostructured films. It is worth mentioning that these properties also depend on the operating temperature and the applied gas concentration on the films. An increase in the operating temperature decreased not only the response and recovery times but also the gas sensitivity of the nanocrystalline films. This shortcoming could be solved by using the amorphous nanostructured Te films which, even at 22 °C, exhibited higher gas sensitivity and shorter response and recovery times by more than one order of magnitude in comparison to the nanocrystalline Te films. These results were interpreted in terms of an increase in disorder (amorphization), leading to an increase in the surface chemical activity of chalcogenides, as well as an increase in the active surface area due to substrate porosity.

scholarly journals Tin Disulfide-Coated Microfiber for Humidity Sensing with Fast Response and High Sensitivity

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 648
Author(s):  
Aijie Liang ◽  
Jingyuan Ming ◽  
Wenguo Zhu ◽  
Heyuan Guan ◽  
Xinyang Han ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
Small Diameter ◽  
High Sensitivity ◽  
Large Change ◽  
Small Variation ◽  
Response Speed ◽  
Fast Response ◽  
Tin Disulfide ◽  
Recovery Times ◽  
Response And Recovery

Breath monitoring is significant in assessing human body conditions, such as cardiac and pulmonary symptoms. Optical fiber-based sensors have attracted much attention since they are immune to electromagnetic radiation, thus are safe for patients. Here, a microfiber (MF) humidity sensor is fabricated by coating tin disulfide (SnS2) nanosheets onto the surface of MF. The small diameter (~8 μm) and the long length (~5 mm) of the MF promise strong interaction between guiding light and SnS2. Thus, a small variation in the relative humidity (RH) will lead to a large change in optical transmitted power. A high RH sensitivity of 0.57 dB/%RH is therefore achieved. The response and recovery times are estimated to be 0.08 and 0.28 s, respectively. The high sensitivity and fast response speed enable our SnS2-MF sensor to monitor human breath in real time.

Synthesis of Novel Pd Nanosponges for Non-Enzymatic Glucose Sensor

2020 ◽  
Vol 20 (12) ◽  
pp. 7333-7341
Author(s):  
Feng Chen ◽  
Jing-Hao Li ◽  
Yu-Chen Chi ◽  
Zhen-Hua Dan ◽  
Feng-Xiang Qin
Keyword(s):  
Glucose Sensor ◽  
High Sensitivity ◽  
Cost Effective ◽  
Active Surface ◽  
Glucose Sensing ◽  
Active Surface Area ◽  
Long Term Stability ◽  
High Uniformity ◽  
One Step ◽  
The Cost

A unique nanostructured electrocatalyst based on Palladium (Pd) nanosponge architecture is synthesized by one-step dealloying of the amorphous alloy precursor with low Pd concentration. The sponge-like nanostructure with hollow interiors enables sufficient contact between reactants andboth the interior and exterior surfaces. The results of cyclic voltammetry reveal that the as-prepared Pd nanosponge exhibits high sensitivity of 32 μA mM−1 cm−2 in a wide linear range (1–18 mM), and long-term stability toward glucose electro-oxidation. The Pd nanosponge also manifests detection limit as low as 2.0 μM (S/N = 3) and high selectivity for glucose sensing. The enhanced catalytic activity of the Pd nanosponge is attributed to the bimetallic synergistic effect and the large active surface area of the high-uniformity porous structure. The facile synthesis of the cost-effective Pd nanosponge with superior electrocatalytic performance makes it hold great potentials for biosensor and other catalysis applications.

scholarly journals Ruthenium Decorated Polypyrrole Nanoparticles for Highly Sensitive Hydrogen Gas Sensors Using Component Ratio and Protonation Control

Polymers ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1427
Author(s):  
Jungkyun Oh ◽  
Jun Seop Lee ◽  
Jyongsik Jang
Keyword(s):  
Active Surface ◽  
Fast Response ◽  
Hydrogen Gas ◽  
Active Surface Area ◽  
Component Ratio ◽  
Ambient Conditions ◽  
Density Control ◽  
Highly Sensitive ◽  
Hydrogen Gas Sensors ◽  
Polypyrrole Nanoparticles

Despite being highly flammable at lower concentrations and causing suffocation at higher concentrations, hydrogen gas continues to play an important role in various industrial processes. Therefore, an appropriate monitoring system is crucial for processes that use hydrogen. In this study, we found a nanocomposite comprising of ruthenium nanoclusters decorated on carboxyl polypyrrole nanoparticles (Ru_CPPy) to be successful in detecting hydrogen gas through a simple sonochemistry method. We found that the morphology and density control of the ruthenium component increased the active surface area to the target analyte (hydrogen molecule). Carboxyl polypyrrole (CPPy) in the nanocomposite was protonated to increase the charge transfer rate during gas detection. This material-based sensor electrode was highly sensitive (down to 0.5 ppm) toward hydrogen gas and had a fast response and recovery time under ambient conditions. The sensing ability of the electrode was maintained up to 15 days without structure deformations.

High sensitivity and fast response and recovery times in a ZnO nanorod array/p-Si self-powered ultraviolet detector

2012 ◽  
Vol 101 (26) ◽  
pp. 261108 ◽  
Author(s):  
J. J. Hassan ◽  
M. A. Mahdi ◽  
S. J. Kasim ◽  
Naser M. Ahmed ◽  
H. Abu Hassan ◽  
...  
Keyword(s):  
High Sensitivity ◽  
Nanorod Array ◽  
Fast Response ◽  
Zno Nanorod ◽  
Ultraviolet Detector ◽  
Recovery Times ◽  
Response And Recovery ◽  
Zno Nanorod Array ◽  
Self Powered

A Flexible Humidity Sensor Based on Co3O4 Nanoneedles with High Sensitivity and Quick Response

2020 ◽  
Vol 15 (7) ◽  
pp. 870-874
Author(s):  
Qi Qi ◽  
Qi Wang ◽  
Nanliu Liu ◽  
Xiaoping Zheng ◽  
Xiongjie Ding ◽  
...  
Keyword(s):  
Humidity Sensor ◽  
High Sensitivity ◽  
Current Sensor ◽  
Quick Response ◽  
Bending Tests ◽  
Humidity Sensing ◽  
Recovery Times ◽  
Response And Recovery ◽  
Sensing Performance ◽  
Semilogarithmic Scale

A flexible humidity sensor has been realized based on Co3O4 nanoneedles via a deposition technique. High humidity sensing and excellent flexible properties are observed in the tests. The impedance of the as-prepared sensor decreases by nearly three orders of magnitude with increasing relative humidity (RH) from 11% to 95% on a semilogarithmic scale. The response and recovery times are about 3 and 6 s respectively. The maximum hysteresis is less than 4% under 80% RH. No obvious changes for the sensing performance can be obtained after 100 bending/extending cycles and bending tests. These performances make the current sensor a good candidate for flexible humidity detection.

scholarly journals Facile Fabrication of Self-Similar Hierarchical Micro-Nano Structures for Multifunctional Surfaces via Solvent-Assisted UV-Lasering

Micromachines ◽  
2020 ◽  
Vol 11 (7) ◽  
pp. 682 ◽  
Author(s):  
Shuo Zhang ◽  
Qin Jiang ◽  
Yi Xu ◽  
Chuan Fei Guo ◽  
Zhigang Wu
Keyword(s):  
High Efficiency ◽  
Hierarchical Structures ◽  
High Sensitivity ◽  
Active Surface ◽  
Active Surface Area ◽  
Application Development ◽  
Nano Structures ◽  
Self Similar ◽  
Bending Sensor ◽  
Light Absorbance

Cross-scale self-similar hierarchical micro–nano structures in living systems often provide unique features on surfaces and serve as inspiration sources for artificial materials or devices. For instance, a highly self-similar structure often has a higher fractal dimension and, consequently, a larger active surface area; hence, it would have a super surface performance compared to its peer. However, artificial self-similar surfaces with hierarchical micro–nano structures and their application development have not yet received enough attention. Here, by introducing solvent-assisted UV-lasering, we establish an elegant approach to fabricate self-similar hierarchical micro–nano structures on silicon. The self-similar structure exhibits a super hydrophilicity, a high light absorbance (>90%) in an ultra-broad spectrum (200–2500 nm), and an extraordinarily high efficiency in heat transfer. Through further combinations with other techniques, such surfaces can be used for capillary assembling soft electronics, surface self-cleaning, and so on. Furthermore, such an approach can be transferred to other materials with minor modifications. For instance, by doping carbon in polymer matrix, a silicone surface with hierarchical micro–nano structures can be obtained. By selectively patterning such hierarchical structures, we obtained an ultra-high sensitivity bending sensor. We believe that such a fabrication technique of self-similar hierarchical micro–nano structures may encourage researchers to deeply explore the unique features of functional surfaces with such structures and to further discover their potentials in various applications in diverse directions.

scholarly journals Study of Two Vanadium Based Materials as Working Electrode for Developing A Selective Mixed-Potential Ammonia Sensor

Proceedings ◽  
2018 ◽  
Vol 2 (13) ◽  
pp. 770
Author(s):  
Gita Nematbakhsh Abkenar ◽  
Jean-Paul Viricelle ◽  
Mathilde Rieu ◽  
Philippe Breuil
Keyword(s):  
Reference Electrode ◽  
High Sensitivity ◽  
Fast Response ◽  
Mixed Potential ◽  
Ammonia Sensor ◽  
Ammonia Gas ◽  
Recovery Times ◽  
Response And Recovery ◽  
Increasing Temperature ◽  
Ammonia Gas Sensors

Mixed potential ammonia gas sensors were fabricated by using two sensing materials of Ni3V2O8 and Au-V2O5 as working electrodes, YSZ as electrolyte and platinum as reference electrode. The results have shown that the Ni3V2O8 sensors show cross-sensitivity toward NO gas. However, Au-V2O5 working electrodes displayed a high sensitivity to NH3 as well as fast response and recovery times at high temperatures. Furthermore, the results indicate that the selectivity of Au-V2O5 sensors increases by increasing temperature.

scholarly journals Ethanol Gas Sensitivity Sensor Based on Roughened POF Taper of Modified Polypyrrole Films

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 989 ◽  
Author(s):  
Wenyi Liu ◽  
Yanjun Hu ◽  
Yulong Hou
Keyword(s):  
Low Cost ◽  
High Sensitivity ◽  
Chemical Oxidation ◽  
Gas Sensitivity ◽  
Polypyrrole Films ◽  
Shape Structure ◽  
Recovery Times ◽  
Bending Radius ◽  
Response And Recovery ◽  
Gas Response

The three polypyrrole (PPy) films with different mixture ratios, namely PPy1, PPy2, and PPy3, were synthesized by chemical oxidation with pyrrole and ferric chloride (FeCl3). The roughened plastic optical fiber (POF) taper assembled PPy films (POF-PPy1, POF-PPy2, and POF-PPy3) were facilely prepared and bent U shape structure for testing ethanol gas at room temperature. The morphologies of the PPy films and the roughened POF taper were studied using electron microscopy. The effect of the three PPy films on the gas response was investigated and the results showed that the POF-PPy2 exhibited a high sensitivity of 5.08 × 10−5 dB/ppm. The detection limit of the sensor was 140 ppm and its response and recovery times were 5 s and 8 s, respectively. The results also showed that as the bending radius decreased, the response and recovery times gradually shortened, while the output power increased. In addition, the proposed sensor has advantages of a low cost and simple structure.

scholarly journals 3D Electrochemical Sensor and Microstructuration Using Aerosol Jet Printing

Sensors ◽  
2021 ◽  
Vol 21 (23) ◽  
pp. 7820
Author(s):  
Tiziano Fapanni ◽  
Emilio Sardini ◽  
Mauro Serpelloni ◽  
Sarah Tonello
Keyword(s):  
Electrochemical Sensor ◽  
Surface Area ◽  
Electrochemical Sensors ◽  
Basic Research ◽  
High Sensitivity ◽  
Active Surface ◽  
Active Surface Area ◽  
Contact Printing ◽  
Jet Printing ◽  
Aerosol Jet Printing

Electrochemical sensors are attracting great interest for their different applications. To improve their performances, basic research focuses on two main issues: improve their metrological characteristics (e.g., repeatability, reusability and sensitivity) and investigate innovative fabrication processes. In this work, we demonstrate an innovative microstructuration technique aimed at increasing electrochemical sensor sensitivity to improve electrode active area by an innovative fabrication technique. The process is empowered by aerosol jet printing (AJP), an additive-manufacturing and non-contact printing technique that allows depositing functional inks in precise patterns such as parallel lines and grids. The 3D printed microstructures increased the active surface area by up to 130% without changing the substrate occupancy. Further, electrochemical detection of ferro/ferri-cyanide was used to evaluate the sensitivity of the electrodes. This evaluation points out a sensitivity increase of 2.3-fold on average between bare and fully microstructured devices. The increase of surface area and sensitivity are well linearly correlated as expected, verifying the fitness of our production process. The proposed microstructuration is a viable solution for many applications that requires high sensitivity, and the proposed technique, since it does not require masks or complex procedures, turns out to be flexible and applicable to infinite construction geometries.

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