High Sensitivity of Ammonia Sensor through 2D Black Phosphorus/Polyaniline Nanocomposite

Recently, as a two-dimensional (2D) material, black phosphorous (BP) has attracted more and more attention. However, few efforts have been made to investigate the BP/polyaniline (PANI) nanocomposite for ammonia (NH3) gas sensors. In this work, the BP/PANI nanocomposite as a novel sensing material for NH3 detection, has been synthesized via in situ chemical oxidative polymerization, which is then fabricated onto the interdigitated transducer (IDTs). The electrical properties of the BP/PANI thin film are studied in a large detection range from 1 to 4000 ppm, such as conduction mechanism, response, reproducibility, and selectivity. The experimental result indicates that the BP/PANI sensor shows higher sensitivity and larger detection range than that of PANI. The BP added into PANI, that may enlarge the specific surface area, obtain the special trough structure for gas channels, and form the p–π conjugation system and p–p isotype heterojunctions, which are beneficial to increase the response of BP/PANI to NH3 sensing. Meanwhile, in order to support the discussion result, the structure and morphology of the BP/PANI are respectively measured by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV−vis), transmission electron microscopy (TEM), and field emissions scanning electron microscopy (SEM). Moreover, the sensor shows good reproducibility, and fast response and recovery behavior, on NH3 sensing. In addition, this route may offer the advantages of an NH3 sensor, which are of simple structure, low cost, easy to assemble, and operate at room temperature.

Download Full-text

Nanocoating of Polyaniline Layer on the Surface of Graphene Sheets for Ammonia Gas Detection

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.557-559.1803 ◽

2012 ◽

Vol 557-559 ◽

pp. 1803-1806 ◽

Cited By ~ 1

Author(s):

Ya Meng Cai ◽

Zong Yi Qin ◽

Zhe Zhou

Keyword(s):

Oxidative Polymerization ◽

High Sensitivity ◽

Fast Response ◽

Thin Layers ◽

Graphene Sheets ◽

Ammonia Gas ◽

Resistive Sensor ◽

Response And Recovery ◽

Nanocomposite Sensors

Polyaniline thin layers were successfully coated on the surface of graphene sheets through in situ chemical oxidative polymerization. By integrating into a resistive sensor design, the sensing properties of the nanocomposites were evaluated. It is found that the nanocomposite sensors exhibited high sensitivity with fast response and recovery time, and good reproducibility charactics for ammonia gas at room temperature even exposed to low concentration of 10 ppm, implying that the nanocomposite could be a promising candidate as a gas sensor for ammonia gas.

Download Full-text

Fast Response Isopropanol Sensing Properties with Sintered BiFeO3 Nanocrystals

Materials ◽

10.3390/ma13173829 ◽

2020 ◽

Vol 13 (17) ◽

pp. 3829 ◽

Cited By ~ 1

Author(s):

Hongxiang Xu ◽

Junhua Xu ◽

Junlin Wei ◽

Yamei Zhang

Keyword(s):

Gas Sensing ◽

Fast Response ◽

Gas Detection ◽

Detection Range ◽

Sensing Properties ◽

Working Temperature ◽

Sensing Material ◽

Gas Sensing Properties ◽

Response And Recovery ◽

Optimum Working

BiFeO3 nanocrystals were applied as the sensing material to isopropanol. The isopropanol sensor based on BiFeO3 nanocrystals shows excellent gas-sensing properties at the optimum working temperature of 240 °C. The sensitivity of as-prepared sensor to 100 ppm isopropanol is 31 and its response and recovery time is as fast as 6 and 17 s. The logarithmic curves of the sensitivity and concentration of BiFeO3 sensors are a very good linear in the low detection range of 2–100 ppm. In addition, the gas sensing mechanism is also discussed. The results suggest that the BiFeO3 nanomaterial can be potentially applied in isopropanol gas detection.

Download Full-text

A Room-Temperature CNT/Fe3O4 Based Passive Wireless Gas Sensor

Sensors ◽

10.3390/s18103542 ◽

2018 ◽

Vol 18 (10) ◽

pp. 3542 ◽

Cited By ~ 5

Author(s):

Tao Guo ◽

Tianhao Zhou ◽

Qiulin Tan ◽

Qianqian Guo ◽

Fengxiang Lu ◽

...

Keyword(s):

Carbon Nanotube ◽

Gas Sensor ◽

Room Temperature ◽

Gas Sensing ◽

Low Cost ◽

Fast Response ◽

Sensing Material ◽

Recovery Times ◽

Response And Recovery ◽

Good Repeatability

A carbon nanotube/Fe3O4 thin film-based wireless passive gas sensor with better performance is proposed. The sensitive test mechanism of LC (Inductance and capacitance resonant) wireless sensors is analyzed and the reason for choosing Fe3O4 as a gas sensing material is explained. The design and fabrication process of the sensor and the testing method are introduced. Experimental results reveal that the proposed carbon nanotube (CNT)/Fe3O4 based sensor performs well on sensing ammonia (NH3) at room temperature. The sensor exhibits not only an excellent response, good selectivity, and fast response and recovery times at room temperature, but is also characterized by good repeatability and low cost. The results for the wireless gas sensor’s performance for different NH3 gas concentrations are presented. The developed device is promising for the establishment of wireless gas sensors in harsh environments.

Download Full-text

High Sensitivity and High Stability QCM Humidity Sensors Based on Polydopamine Coated Cellulose Nanocrystals/Graphene Oxide Nanocomposite

Nanomaterials ◽

10.3390/nano10112210 ◽

2020 ◽

Vol 10 (11) ◽

pp. 2210

Author(s):

Yao Yao ◽

Xianhe Huang ◽

Qiao Chen ◽

Zhen Zhang ◽

Weiwei Ling

Keyword(s):

Graphene Oxide ◽

High Stability ◽

Humidity Sensor ◽

High Sensitivity ◽

Fast Response ◽

Dynamic Resistance ◽

Sensitive Material ◽

Detection Range ◽

Response And Recovery ◽

Humidity Range

In this paper, a high sensitivity and high stability quartz crystal microbalance (QCM) humidity sensor using polydopamine (PDA) coated cellulose nanocrystal (CNC)/graphene oxide (GO) (PDA@CNC/GO) nanocomposite as sensitive material is demonstrated. The PDA@CNC was prepared by the self-polymerization action on the surface of CNC, and it acted as filler material to form functional nanocomposite with GO. The material characteristics of PDA@CNC, CNC/GO and PDA@CNC/GO were analyzed by transmission electron microscope (TEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The experimental results show that the introduction of PDA@CNC into GO film not only effectively enhanced the sensitivity of GO-based nanocomposite-coated QCM sensor but also significantly maintained high stability in the entire humidity range. The PDA@CNC/GO30-coated QCM humidity sensor exhibited a superior response sensitivity up to 54.66 Hz/% relative humidity (RH), while the change rate of dynamic resistance of the sensor in the humidity range of 11.3–97.3% RH is only 14% that is much smaller than that of CNC/GO-coated QCM. Besides, the effect of the PDA@CNC content on the sensitivity and stability of GO-based nanocomposite-coated QCM humidity was also studied. Moreover, other performances of PDA@CNC/GO-coated QCM humidity sensor, including humidity hysteresis, fast response and recovery and long-term stability, were systematically investigated. This work suggests that PDA@CNC/GO nanocomposite is a promising candidate material for realizing high sensitivity and high stability QCM humidity sensor in the entire humidity detection range.

Download Full-text

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

Crystals ◽

10.3390/cryst11060648 ◽

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.

Download Full-text

A Full-Range Flexible and Printed Humidity Sensor Based on a Solution-Processed P(VDF-TrFE)/Graphene-Flower Composite

Nanomaterials ◽

10.3390/nano11081915 ◽

2021 ◽

Vol 11 (8) ◽

pp. 1915

Author(s):

Shenawar Ali Khan ◽

Muhammad Saqib ◽

Muhammad Muqeet Rehman ◽

Hafiz Mohammad Mutee Ur Rehman ◽

Sheik Abdur Rahman ◽

...

Keyword(s):

Active Layer ◽

Humidity Sensor ◽

High Reliability ◽

Full Range ◽

High Sensitivity ◽

Fast Response ◽

Considerable Change ◽

Relative Humidity Range ◽

Response And Recovery ◽

Proportional Relationship

A novel composite based on a polymer (P(VDF-TrFE)) and a two-dimensional material (graphene flower) was proposed as the active layer of an interdigitated electrode (IDEs) based humidity sensor. Silver (Ag) IDEs were screen printed on a flexible polyethylene terephthalate (PET) substrate followed by spin coating the active layer of P(VDF-TrFE)/graphene flower on its surface. It was observed that this sensor responds to a wide relative humidity range (RH%) of 8–98% with a fast response and recovery time of 0.8 s and 2.5 s for the capacitance, respectively. The fabricated sensor displayed an inversely proportional response between capacitance and RH%, while a directly proportional relationship was observed between its impedance and RH%. P(VDF-TrFE)/graphene flower-based flexible humidity sensor exhibited high sensitivity with an average change of capacitance as 0.0558 pF/RH%. Stability of obtained results was monitored for two weeks without any considerable change in the original values, signifying its high reliability. Various chemical, morphological, and electrical characterizations were performed to comprehensively study the humidity-sensing behavior of this advanced composite. The fabricated sensor was successfully used for the applications of health monitoring and measuring the water content in the environment.

Download Full-text

Easy-to-Fabricate K2Pd(SO3)2-Dyed Polyester Fabric with Highly Selective and Fast Response to Carbon Monoxide

Journal of Nanoscience and Nanotechnology ◽

10.1166/jnn.2021.19418 ◽

2021 ◽

Vol 21 (8) ◽

pp. 4400-4405

Author(s):

Junyeop Lee ◽

Nam Gon Do ◽

Dong Hyuk Jeong ◽

Sae-Wan Kim ◽

Maeum Han ◽

...

Keyword(s):

Carbon Monoxide ◽

Color Change ◽

High Sensitivity ◽

Cost Effective ◽

Fast Response ◽

Polyester Fabric ◽

High Porosity ◽

Sensing Material ◽

Sensitivity And Selectivity ◽

And Performance

Carbon monoxide (CO) is an odorless, colorless, tasteless, extremely flammable, and highly toxic gas. It is produced when there is insufficient oxygen supply during the combustion of carbon to produce carbon dioxide (CO2). CO is produced from operating engines, stoves, or furnaces. CO poisoning occurs when CO accumulates in the bloodstream and can result in severe tissue damage or even death. Many types of CO sensors have been reported, including electrochemical, semiconductor metal-oxide, catalytic combustion, thermal conductivity, and infrared absorption-type for the detection of CO. However, despite their excellent selectivity and sensitivity, issues such as complexity, power consumption, and calibration limit their applications. In this study, a fabricbased colorimetric CO sensor is proposed to address these issues. Potassium disulfitopalladate (II) (K2Pd(SO3)2) is dyed on a polyester fabric as a sensing material for selective CO detection. The sensing characteristics and performance are investigated using optical instruments such as RGB sensor and spectrometer. The sensor shows immediate color change when exposed to CO at a concentration that is even lower than 20 ppm before 2 min. The fast response time of the sensor is attributed to its high porosity to react with CO. This easy-to-fabricate and cost-effective sensor can detect and prevent the leakage of CO simultaneously with high sensitivity and selectivity toward CO.

Download Full-text

Gas Sensing Properties of TiO2 and SnO2 Nanopowders Obtained through Gel Combustion

Advances in Science and Technology ◽

10.4028/www.scientific.net/ast.45.1828 ◽

2006 ◽

Vol 45 ◽

pp. 1828-1833

Author(s):

Fabio A. Deorsola ◽

P. Mossino ◽

Ignazio Amato ◽

Bruno DeBenedetti ◽

A. Bonavita ◽

...

Keyword(s):

Response Time ◽

Metal Oxides ◽

Gas Sensing ◽

Low Cost ◽

High Sensitivity ◽

Fast Response ◽

High Specific Surface Area ◽

Research Field ◽

Wide Range ◽

Gel Combustion

Nanostructured semiconductor metal oxides have played a central role in the gas sensing research field, because of their high sensitivity, selectivity and low response time. Among all the processes, developed for the synthesis of nanostructured metal oxides, gel combustion seems to be the most promising route due to low-cost precursors and simplicity of the process. It combines chemical gelation and combustion, involving the formation of a gel from an acqueous solution and an exothermic redox reaction, yielding to very porous and softly agglomerated nanopowders. In this work, nanostructured tin oxide, SnO2, and titanium oxide, TiO2, have been synthesized through gel combustion. Powders showed nanometric particle size and high specific surface area. The so-obtained TiO2 and SnO2 nanopowders have been used as sensitive element of resistive λ sensor and ethanol sensor respectively, realized depositing films of nanopowders dispersed in water onto alumina substrates provided with Pt contacts and heater. TiO2-based sensors showed at high temperature good response, fast response time, linearity in a wide range of O2 concentration and long-term stability. SnO2-based sensors have shown high sensitivity to low concentrations of ethanol at moderate temperature.

Download Full-text

The Effect of rGO-Doping on the Performance of SnO2/rGO Flexible Humidity Sensor

Nanomaterials ◽

10.3390/nano11123368 ◽

2021 ◽

Vol 11 (12) ◽

pp. 3368

Author(s):

Huangping Yan ◽

Zilu Chen ◽

Linyuan Zeng ◽

Zijun Wang ◽

Gaofeng Zheng ◽

...

Keyword(s):

Electron Microscopy ◽

High Performance ◽

Humidity Sensor ◽

High Sensitivity ◽

Polyimide Film ◽

Fast Response ◽

Humidity Sensing ◽

Transmission Electron ◽

Bending Radius ◽

New Applications

The development of a flexible and high-performance humidity sensor is essential to expand its new applications, such as personal health monitoring and early diagnosis. In this work, SnO2/rGO nanocomposites were prepared by one-step hydrothermal method. The effect of rGO-doping on humidity sensing performance was investigated. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction and Raman spectroscopy were used to characterize the nanostructure, morphology and chemical composition of SnO2/rGO nanocomposites. The SnO2/rGO humidity sensitive film was prepared by electrospinning on a polyimide film modified with gold electrodes. The humidity test results show that different doping ratios of rGO have different effects on humidity sensing properties. Among them, the sensor with 2 wt% rGO-doping has a high sensitivity (37,491.2%) within the humidity range as well as the fast response time (80 s) and recover time (4 s). Furthermore, the sensor with 2 wt% rGO-doping remains good flexibility and stability in the case of bending (1000 times). The sensitivity of the 2 wt% rGO-doping sensor at the bending radius (8 mm and 4 mm) is 48,219% and 91,898%, respectively. More importantly, the sensor could reflect different breathing states clearly and track breathing intervals as short as 3 s. The SnO2/rGO flexible humidity sensor with accuracy, flexibility and instantaneity as well as the facile fabrication strategy is conceivable to be applied in the potential application for human health real-time monitoring.

Download Full-text