scholarly journals DYNAMICS OF RESPONSE OF A SENSOR BASED ON A NANOSTRUCTURED TIN DIOXIDE LAYER EXPOSED TO THE ISOPROPANOL VAPORS

2021 ◽  
pp. 708-716
Author(s):  
Никита Александрович Клычков ◽  
Вячеслав Владимирович Симаков ◽  
Илья Владимирович Синёв ◽  
Дмитрий Александрович Тимошенко
Keyword(s):  
Response Time ◽  
Temperature Dependence ◽  
Gas Sensor ◽  
Tin Dioxide ◽  
Molecular Form ◽  
Sol Gel ◽  
Adsorbed Oxygen ◽  
Air Atmosphere ◽  
Chemisorbed Oxygen ◽  
Dioxide Film

С помощью золь-гель технологии синтезированы наноструктурированные газочувствительные пленки диоксида олова. Исследовано влияние температуры на проводимость сенсора в атмосфере очищенного воздуха, на величину отклика сенсора при воздействии паров изопропанола различной концентрации. На температурной зависимости проводимости плёнки диоксида олова в атмосфере чистого воздуха наблюдается локальный минимум. Уменьшение проводимости с ростом температуры в диапазоне 300...350С может быть связано с диссоциацией молекулярной формы адсорбированного кислорода. При температурах выше 350 °С проводимость возрастает из-за десорбции атомарной формы адсорбированного кислорода с поверхности газочувствительного слоя диоксида олова. Обнаружено, что наибольший отклик к газовым пробам достигается при рабочей температуре сенсора порядка 350°С. Предполагается, что это обусловлено наличием на поверхности атомарной формы хемосорбированного кислорода. Проведен анализ концентрационных и температурных зависимостей времени отклика сенсора при воздействии паров изопропанола. Время отклика сенсора монотонно уменьшается с повышением содержания примеси в газовых пробах, по-видимому, из-за увеличения скорости адсорбции частиц примеси из газовой фазы на поверхность газочувствительного слоя. Установлено, что зависимость времени отклика от рабочей температуры имеет аррениусовский вид, что может быть связано с термоактивированными адсорбционно-десорбционными и гетерогенными химическими процессами на поверхности активного слоя сенсора. Nanostructured gas-sensitive tin dioxide films have been synthesized by sol-gel technology. A conductivity vs temperature dependence of a gas sensor into atmosphere of synthetic air has been investigated. A response vs temperature dependence of a gas sensor into atmosphere of isopropanol vapors with various concentrations has been investigated. Local minimum on the temperature dependence of the tin dioxide film conductivity in clean air atmosphere were observed. A decrease in conductivity with increase temperature in the range of 300...350 °C can be associated with a dissociation molecular form of the adsorbed oxygen. At temperatures above 350 °C, conductivity increases because of desorption of the atomic form of the adsorbed oxygen on the surface of gas-sensitive tin dioxide film. The greatest response value is achieved at a sensor temperature equal to 350 °C. It is proposed that the reason is a domination of the atomic form of the chemisorbed oxygen on the surface. The analysis of response time vs concentration and response time vs temperature of gas sensor has been carried out. Sensor response time decreases monotonically with increase admixture substance in gas-probes, apparently because of increase in adsorption rate admixture particles on the surface of gas-sensitive film. It was found that the dependence of the response time on the operating temperature has an Arrhenius form. This may be associated with thermally activated adsorption-desorption processes and heterogeneous chemical reactions on the surface of sensor active layer.

scholarly journals Humidity-Insensitive NO2 Sensors Based on SnO2/rGO Composites

2021 ◽  
Vol 9 ◽  
Author(s):  
Yingyi Wang ◽  
Lin Liu ◽  
Fuqin Sun ◽  
Tie Li ◽  
Ting Zhang ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Gas Sensor ◽  
Chemical Engineering ◽  
Tin Dioxide ◽  
Limit Of Detection ◽  
Sol Gel ◽  
Reduced Graphene ◽  
Real World Applications ◽  
High Level ◽  
P Type

This study reported a novel humidity-insensitive nitrogen dioxide (NO2) gas sensor based on tin dioxide (SnO2)/reduced graphene oxide (rGO) composites through the sol-gel method. The sensor demonstrated ppb-level NO2 detection in p-type sensing behaviors (13.6% response to 750 ppb). Because of the synergistic effect on SnO2/rGO p-n heterojunction, the sensing performance was greatly enhanced compared to that of bare rGO. The limit of detection of sensors was as low as 6.7 ppb under dry air. Moreover, benefited from the formed superhydrophobic structure of the SnO2/rGO composites (contact angle: 149.0°), the humidity showed a negligible influence on the dynamic response (Sg) of the sensor to different concentration of NO2 when increasing the relative humidity (RH) from 0 to 70% at 116°C. The relative conductivity of the sensor to 83% relative humidity was 0.11%. In addition, the response ratio (Sg/SRH) between 750 ppb NO2 and 83% RH was 649.0, indicating the negligible impaction of high-level ambient humidity on the sensor. The as-fabricated humidity-insensitive gas sensor can promise NO2 detection in real-world applications such as safety alarm, chemical engineering, and so on.

scholarly journals Fast response time alcohol gas sensor using nanocrystalline F-doped SnO2 films derived via sol–gel method

2013 ◽  
Vol 36 (4) ◽  
pp. 521-533 ◽  
Author(s):  
SARBANI BASU ◽  
YEONG-HER WANG ◽  
C GHANSHYAM ◽  
PAWAN KAPUR
Keyword(s):  
Response Time ◽  
Gas Sensor ◽  
Sol Gel ◽  
Fast Response ◽  
Gel Method ◽  
Sol Gel Method ◽  
Fast Response Time

scholarly journals MULTIPARAMETRIC RECOGNITION OF ORGANIC VAPORS BY USING A GAS SENSOR BASED ON A NANOSTRUCTURED TIN DIOXIDE FILM

2021 ◽  
pp. 852-859
Author(s):  
Никита Александрович Клычков ◽  
Вячеслав Владимирович Симаков ◽  
Илья Владимирович Синёв ◽  
Дмитрий Александрович Тимошенко
Keyword(s):  
Gas Sensor ◽  
Tin Dioxide ◽  
Saturated Vapor ◽  
Sol Gel ◽  
Statistical Processing ◽  
Gas Mixtures ◽  
Organic Vapors ◽  
Single Sensor ◽  
High Concentrations ◽  
Physical And Chemical

Исследовано влияние паров органических веществ (изопропанола, этанола и ацетона) различной концентрации на отклик сенсоров газа на основе наноструктурированных пленок диоксида олова, синтезированных золь-гель методом. Экспериментально установлено, что напуск газовых проб, содержащих пары органических веществ, приводит к увеличению проводимости наноструктурированных пленок диоксида олова. В области высоких концентраций (более 50% от насыщенного пара) концентрационная зависимость проводимости имеет тенденцию к насыщению. Показана возможность распознавания сорта примесного газа с помощью статистической обработки отклика только одного сенсора при различных концентрациях анализируемой пробы. Определено положение поверхностного донорного уровня примесного газа относительно акцепторного уровня кислорода и теплота десорбции частиц исследуемых газов. Предложен новый метод мультипараметрического распознавания газовых смесей, основанный на использование в качестве признаков классификации физико-химических параметров анализируемых газов, не зависящих от их концентрации. Установлено, что предложенный метод мультипараметрического распознавания газовых смесей имеет более высокую надежность по сравнению со стандартными методами, основанными на анализе отклика сенсоров газа. The influence of organic vapors (isopropanol, ethanol, and acetone) with different concentrations in air on a response gas sensor based on nanostructured tin dioxide films synthesized by the sol-gel method was studied. It was found experimentally that inject of the gas mixtures containing organic vapors into measure chamber results to an increase of the conductivity of nanostructured tin dioxide films. In the area of high concentrations (more than 50% of saturated vapor), the concentration dependence of conductivity trends to saturation. The recognizing possibility of species gas admixture by using statistical processing of response only single sensor at different analyzed gas mixture concentrations is validated. The surface donor level of gas-reducing relative to acceptor level oxygen and desorption heat of gas particle were determined. A new method based multiparametric recognition gas mixtures is proposed based on using concentration-independent physical and chemical parameters of analyzed gases as classification properties. It is shown that proposed multiparametric recognition method has higher reliability in comparison with standard methods based on the analysis gas sensor response.

Preparation and properties of a long time durable superhydrophilic titanium dioxide film obtained by a sol-gel process

2017 ◽  
Vol 59 (1) ◽  
pp. 81-85
Author(s):  
Jianjun Zhang ◽  
Hao Zeng ◽  
Chun Liu ◽  
Chao Li ◽  
Sude Ma ◽  
...  
Keyword(s):  
Titanium Dioxide ◽  
Sol Gel ◽  
Titanium Dioxide Film ◽  
Sol Gel Process ◽  
Long Time ◽  
Dioxide Film

scholarly journals Ammonia Gas Sensing Characteristic of P3HT-rGO-MWCNT Composite Films

2021 ◽  
Vol 11 (15) ◽  
pp. 6675
Author(s):  
Tran Si Trong Khanh ◽  
Tran Quang Trung ◽  
Le Thuy Thanh Giang ◽  
Tran Quang Nguyen ◽  
Nguyen Dinh Lam ◽  
...  
Keyword(s):  
Response Time ◽  
Gas Sensor ◽  
Gas Sensing ◽  
Composite Films ◽  
Weight Ratio ◽  
Film Surface ◽  
Relative Sensitivity ◽  
Ammonia Gas ◽  
Casting Technique ◽  
Multi Walled Carbon Nanotubes

In this work, the P3HT:rGO:MWCNTs (PGC) nanocomposite film applied to the ammonia gas sensor was successfully fabricated by a drop-casting technique. The results demonstrated that the optimum weight ratio of the PGC nanocomposite gas sensor is 20%:60%:20% as the weight ratio of P3HT:rGO:MWCNTs (called PGC-60). This weight ratio leads to the formation of nanostructured composites, causing the efficient adsorption/desorption of ammonia gas in/out of the film surface. The sensor based on PGC-60 possessed a response time of 30 s, sensitivity up to 3.6% at ammonia gas concentration of 10 ppm, and relative sensitivity of 0.031%/ppm. These results could be attributed to excellent electron transportation of rGO, the main adsorption activator to NH3 gas of P3HT, and holes move from P3HT to the cathodes, which works as charge “nano-bridges” carriers of Multi-Walled Carbon Nanotubes (MWCNTs). In general, these three components of PGC sensors have significantly contributed to the improvement of both the sensitivity and response time in the NH3 gas sensor.

scholarly journals Decoration of CuO NWs Gas Sensor with ZnO NPs for Improving NO2 Sensing Characteristics

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2103 ◽  
Author(s):  
Tae-Hee Han ◽  
So-Young Bak ◽  
Sangwoo Kim ◽  
Se Hyeong Lee ◽  
Ye-Ji Han ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensors ◽  
Sol Gel ◽  
Oxide Semiconductor ◽  
Zno Nps ◽  
X Ray ◽  
Semiconductor Gas Sensor ◽  
Initial Resistance ◽  
P Type ◽  
Sensing Characteristics

This paper introduces a method for improving the sensitivity to NO2 gas of a p-type metal oxide semiconductor gas sensor. The gas sensor was fabricated using CuO nanowires (NWs) grown through thermal oxidation and decorated with ZnO nanoparticles (NPs) using a sol-gel method. The CuO gas sensor with a ZnO heterojunction exhibited better sensitivity to NO2 gas than the pristine CuO gas sensor. The heterojunction in CuO/ZnO gas sensors caused a decrease in the width of the hole accumulation layer (HAL) and an increase in the initial resistance. The possibility to influence the width of the HAL helped improve the NO2 sensing characteristics of the gas sensor. The growth morphology, atomic composition, and crystal structure of the gas sensors were analyzed using field-emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy, and X-ray diffraction, respectively.

Localized Collection of Airborne Analytes: A Transport Driven Approach to Improve the Response Time of Existing Gas Sensor Designs including SERS based Detection of Small Molecules

2015 ◽  
Vol 1746 ◽  
Author(s):  
Jun Fang ◽  
Se-Chul Park ◽  
Leslie Schlag ◽  
Thomas Stauden ◽  
Joerg Pezoldt ◽  
...  
Keyword(s):  
Response Time ◽  
Small Molecules ◽  
Gas Sensor ◽  
Recent Trend ◽  
Active Area ◽  
Analyte Concentration ◽  
Analyte Molecule ◽  
Collection Rate ◽  
Molecular Binding ◽  
Increased Sensitivity

ABSTRACTThe detection of single molecular binding events has been a recent trend in sensor research introducing various sensor designs where the active sensing elements are nanoscopic in size. Currently, diffusion-only-transport is often used and it becomes increasingly unlikely for an analyte molecule to “find” and interact with sensing structures where the active area is shrunk in size, trading an increased sensitivity with a long response time. This report introduces electrodynamic nanolens based analyte concentration concepts to transport airborne analytes to nanoscopic sensing points to improve the response time of existing gas sensor designs. In all cases we find that the collection rate is several orders of magnitudes higher than in the case where the collection is driven by diffusion.

Effect of aging heat time and annealing temperature on the properties of nanocrystalline tin dioxide thin films

2017 ◽  
Vol 31 (12) ◽  
pp. 1750114
Author(s):  
Imad H. Kadhim ◽  
H. Abu Hassan
Keyword(s):  
Thin Films ◽  
Tin Dioxide ◽  
Sol Gel ◽  
Stable Solution ◽  
Solution Viscosity ◽  
Pure Ethanol ◽  
Rutile Structure ◽  
Heat Time ◽  
Chloride Dihydrate ◽  
P Type

Nanocrystalline tin dioxide (SnO2) thin films have been successfully prepared by sol–gel spin-coating technique on p-type Si (100) substrates. A stable solution was prepared by mixing tin(II) chloride dihydrate, pure ethanol, and glycerin. Temperature affects the properties of SnO2 thin films, particularly the crystallite size where the crystallization of SnO2 with tetragonal rutile structure is achieved when thin films that prepared under different aging heat times are annealed at 400[Formula: see text]C. By increasing aging heat time in the presence of annealing temperatures the FESEM images indicated that the thickness of the fabricated film was directly proportional to solution viscosity, increasing from approximately 380 nm to 744 nm, as well as the crystallization of the thin films improved and reduced defects.

Temperature dependence of the photochromism of naphthopyrans in functionalized sol–gel thin films

2006 ◽  
Vol 16 (18) ◽  
pp. 1734-1740 ◽  
Author(s):  
Rosario Pardo ◽  
Marcos Zayat ◽  
David Levy
Keyword(s):  
Thin Films ◽  
Temperature Dependence ◽  
Sol Gel
Sign in / Sign up

Export Citation Format

Share Document