scholarly journals Rheotaxially Grown and Vacuum Oxidized SnOx Nanolayers for NO2 Sensing Characteristics at ppb Level and Room Temperature

Sensors ◽  
2020 ◽  
Vol 20 (5) ◽  
pp. 1323
Author(s):  
Barbara Lyson-Sypien ◽  
Monika Kwoka
Keyword(s):  
Detection Limit ◽  
Photoelectron Spectroscopy ◽  
Room Temperature ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
Relative Concentration ◽  
Processing Technique ◽  
Air Exposure ◽  
Carbon Contamination ◽  
Sensing Characteristics

This work presents, for the very first time, very promising nitrogen dioxide (NO2) sensing characteristics of SnOx nanolayers obtained by the innovative and unique rheotaxial growth and vacuum oxidation (RGVO) processing technique. The NO2 gas sensing experiments were performed using the novel surface photovoltage gas sensing device. The measured detection limit at room temperature (RT) is as low as 10 ppb NO2 in synthetic air, whereas the detection limit calculated on the basis of signal to noise ratio is around 6 ppb NO2. For the complementary study of surface chemistry of RGVO SnOx nanolayers, including nonstoichiometry, presence of carbon contamination and surface bondings, the X-ray photoelectron spectroscopy (XPS) method was applied. The SnOx RGVO samples reveal nonstoichiometry because the relative concentration [O]/[Sn] equals 0.94 for the as deposited sample and increases upon subsequent air exposure and NO2 sensing. Moreover, carbon contamination has been recognized after exposing the RGVO SnOx nanolayers to the air and during the NO2 detection.

scholarly journals Improved Cl2 sensing characteristics of reduced graphene oxide when decorated with copper phthalocyanine nanoflowers

RSC Advances ◽  
2017 ◽  
Vol 7 (41) ◽  
pp. 25229-25236 ◽  
Author(s):  
Sanjeev Kumar ◽  
Navdeep Kaur ◽  
Anshul Kumar Sharma ◽  
Aman Mahajan ◽  
R. K. Bedi
Keyword(s):  
Graphene Oxide ◽  
Detection Limit ◽  
Reduced Graphene Oxide ◽  
Room Temperature ◽  
Copper Phthalocyanine ◽  
Gas Sensing ◽  
Sensing Platform ◽  
Reduced Graphene ◽  
Sensing Characteristics

A novel gas sensing platform involving a hybrid of reduced graphene oxide (rGO) sheets with unsubstituted copper phthalocyanine (CuPc) nanoflowers has been explored as a room temperature ppb level chemiresistive chlorine (Cl2) sensor with a detection limit as low as 1.97 ppb.

scholarly journals Studies of NO2 Gas-Sensing Characteristics of a Novel Room-Temperature Surface-Photovoltage Gas Sensor Device

Sensors ◽  
2020 ◽  
Vol 20 (2) ◽  
pp. 408 ◽  
Author(s):  
Monika Kwoka ◽  
Jacek Szuber
Keyword(s):  
Gas Sensor ◽  
Gas Flow ◽  
Room Temperature ◽  
Gas Sensing ◽  
Relative Concentration ◽  
Surface Photovoltage ◽  
Sensor Device ◽  
Gas Atmosphere ◽  
Sensing Characteristics ◽  
Temperature Surface

In this work the characteristics of a novel type of room temperature NO2 gas sensor device based on the surface photovoltage effect are described. It was shown that for our SPV gas sensor device, using porous sputtered ZnO nanostructured thin films as the active gas sensing electrode material, the basic gas sensor characteristics in a toxic NO2 gas atmosphere are strongly dependent on the target NO2 gas flow rate. Moreover, it was also confirmed that our SPV gas sensor device is able to detect the lowest NO2 relative concentration at the level of 125 ppb, with respect to the commonly assumed signal-to-noise (S/N) ratio, as for the commercial devices.

scholarly journals Transforming Pt-SnO2 Nanoparticles into Pt-SnO2 Composite Nanoceramics for Room-Temperature Hydrogen-Sensing Applications

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2123
Author(s):  
Ming Liu ◽  
Caochuang Wang ◽  
Pengcheng Li ◽  
Liang Cheng ◽  
Yongming Hu ◽  
...  
Keyword(s):  
Room Temperature ◽  
Gas Sensing ◽  
Sintering Temperature ◽  
Sno2 Nanoparticles ◽  
Hydrogen Sensing ◽  
Sensing Applications ◽  
Nanostructured Metal Oxides ◽  
Low Dimensional ◽  
Sensing Characteristics ◽  
Nanostructured Metal

Many low-dimensional nanostructured metal oxides (MOXs) with impressive room-temperature gas-sensing characteristics have been synthesized, yet transforming them into relatively robust bulk materials has been quite neglected. Pt-decorated SnO2 nanoparticles with 0.25–2.5 wt% Pt were prepared, and highly attractive room-temperature hydrogen-sensing characteristics were observed for them all through pressing them into pellets. Some pressed pellets were further sintered over a wide temperature range of 600–1200 °C. Though the room-temperature hydrogen-sensing characteristics were greatly degraded in many samples after sintering, those samples with 0.25 wt% Pt and sintered at 800 °C exhibited impressive room-temperature hydrogen-sensing characteristics comparable to those of their counterparts of as-pressed pellets. The variation of room-temperature hydrogen-sensing characteristics among the samples was explained by the facts that the connectivity between SnO2 grains increases with increasing sintering temperature, and Pt promotes oxidation of SnO2 at high temperatures. These results clearly demonstrate that some low-dimensional MOX nanocrystals can be successfully transformed into bulk MOXs with improved robustness and comparable room-temperature gas-sensing characteristics.

scholarly journals A Novel Type Room Temperature Surface Photovoltage Gas Sensor Device 

2018 ◽  
Author(s):  
Monika Kwoka ◽  
Michal A. Borysiewicz ◽  
Pawel Tomkiewicz ◽  
Anna Piotrowska ◽  
Jacek Szuber
Keyword(s):  
Gas Sensor ◽  
Room Temperature ◽  
Gas Sensing ◽  
Signal To Noise Ratio ◽  
High Sensitivity ◽  
Fast Response ◽  
Surface Photovoltage ◽  
Kelvin Probe ◽  
Sensor Device ◽  
Developed Surface

In this paper a novel type of a highly sensitive gas sensor device based on the surface photovoltage effect is described. The developed surface photovoltage gas sensor is based on a reverse Kelvin probe approach. As the active gas sensing electrode the porous ZnO nanostructured thin films are used deposited by the direct current (DC) reactive magnetron sputtering method exhibiting the nanocoral surface morphology combined with an evident surface nonstoichiometry related to the unintentional surface carbon and water vapor contaminations. Among others, the demonstrated SPV gas sensor device exhibits a high sensitivity of 1 ppm to NO2 with a signal to noise ratio of about 50 and a fast response time of several seconds under the room temperature conditions.

Highly sensitive and selective room-temperature NO2 gas-sensing characteristics of SnOX-based p-type thin-film transistor

2019 ◽  
Vol 288 ◽  
pp. 625-633 ◽  
Author(s):  
Hwan-Seok Jeong ◽  
Min-Jae Park ◽  
Soo-Hun Kwon ◽  
Hyo-Jun Joo ◽  
Hyuck-In Kwon
Keyword(s):  
Thin Film ◽  
Room Temperature ◽  
Gas Sensing ◽  
Thin Film Transistor ◽  
Highly Sensitive ◽  
P Type ◽  
Sensing Characteristics

Fe3O4/rGO nanocomposite: synthesis and enhanced NOxgas-sensing properties at room temperature

RSC Advances ◽  
2016 ◽  
Vol 6 (43) ◽  
pp. 37085-37092 ◽  
Author(s):  
Ying Yang ◽  
Li Sun ◽  
Xiangting Dong ◽  
Hui Yu ◽  
Tingting Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Detection Limit ◽  
Response Time ◽  
Reduced Graphene Oxide ◽  
Room Temperature ◽  
Gas Sensing ◽  
High Sensitivity ◽  
Short Response Time ◽  
Reduced Graphene ◽  
Sensing Performance

Fe3O4nanoparticles-decorated reduced graphene oxide nanocomposites have been successfully synthesized using solvothermal-pyrolytic method. They have superior gas sensing performance with low detection limit, high sensitivity and short response time.

scholarly journals New Design of ZnO Nanorod- and Nanowire-Based NO2 Room-Temperature Sensors Prepared by Hydrothermal Method

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Vo Thanh Duoc ◽  
Dang Thi Thanh Le ◽  
Nguyen Duc Hoa ◽  
Nguyen Van Duy ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Hydrothermal Method ◽  
Room Temperature ◽  
Gas Sensing ◽  
Local Heating ◽  
Zno Nanorods ◽  
Hydrothermal Process ◽  
Maximal Response ◽  
Sensor Applications ◽  
Sensing Characteristics ◽  
Sensing Performance

Room-temperature gas sensors are attracting attention because of their low power consumption, safe operation, and long-term stability. Herein, ZnO nanorods (NRs) and nanowires (NWs) were on-chip grown via a facile hydrothermal method and used for room-temperature NO2 gas sensor applications. The ZnO NRs were obtained by a one-step hydrothermal process, whereas the NWs were obtained by a two-step hydrothermal process. To obtain ZnO NW sensor, the length of NRs was controlled short enough so that none of the nanorod-nanorod junction was made. Thereafter, the NWs were grown from the tips of no-contact NRs to form nanowire-nanowire junctions. The gas-sensing characteristics of ZnO NRs and NWs were tested against NO2 gas at room temperature for comparison. The gas-sensing characteristics of the sensors were also tested at different applied voltages to evaluate the effect of the self-activated gas-sensing performance. Results show that the diameter of ZnO NRs and NWs is the dominant parameter of their NO2 gas-sensing performance at room temperature. In addition, self-activation by local heating occurred for both sensors, but because the NWs were smaller and sparser than the NRs, local heating thus required a lower applied voltage with maximal response compared with the NRs.

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