Sensing mechanism of low temperature NO2 sensing with top–bottom electrode (TBE) geometry

Haidry, Azhar Ali; Cetin, Cagdas; Kelm, Klemens; Saruhan, Bilge

doi:10.1016/j.snb.2016.03.016

Cited by 14 publications

(9 citation statements)

References 35 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Under ordinary circumstances, TiO 2 shows n-type response to reducing gases [19,20] and oxidizing gases [21]. Irrespective to the operating temperature, all sensors showed as expected n-type response to overall range of H 2 concentrations (40- Fig.…”

mentioning

confidence: 62%

See 1 more Smart Citation

Cost-effective fabrication of polycrystalline TiO2 with tunable n/p response for selective hydrogen monitoring

Haidry

Sun

Saruhan

et al. 2018

Sensors and Actuators B: Chemical

Self Cite

View full text Add to dashboard Cite

In this report, we demonstrate a simple and cost-effective strategy to prepare polycrystalline rutile TiO2 based gas sensors with tunable n/p type conductivity inversion depending on gas concentration, operating temperature and applied voltage. The effect of surface modification by Ag and Ni thin film on structural, morphological and gas sensor characteristics is studied in detail. The sensors show excellent sensing performance in terms of sensitivity (~25% for 0.1 vol. % H2 diluted in technical air), selectivity (selectivity factor for 0.1 vol. % H2 is about ~24 against NH3, CH4, NO2 and ~8 for CO), stability (both long-term and short-term) and reaction times (~0.7 min for 0.1 vol. % H2). The aforementioned performance is recorded at 300 °C with applied voltage of 0.1 V. Excluding the power consumption of sensor heater-5 watt), this applied voltage 0.1 V can reduce the power-10 watt. We found a critical point, defined with threshold-concentration (CTh), threshold-temperature (TTh) and criticalvoltage (VC), at which the conductivity inverses from one kind to another, something intriguing to novel sensing phenomena that can be exploited to tailor the selectivity of the sensors. A physical-chemical sensing model is presented to understand the aforesaid peculiar occurrence.

show abstract

mentioning

confidence: 62%

“…NO 2 , O 2 ). configuration [19][20][21]. However, there are only limited reports [10][11] in the literature on the conductivity transition behaviour of TiO 2 .…”

Section: Introductionmentioning

confidence: 99%

Cost-effective fabrication of polycrystalline TiO2 with tunable n/p response for selective hydrogen monitoring

Haidry

Sun

Saruhan

et al. 2018

Sensors and Actuators B: Chemical

Self Cite

View full text Add to dashboard Cite

show abstract

“…Metal ions of different valence states act as donors or acceptors in TiO 2 , respectively, which can change the electrical conductivity of TiO 2 , thereby having effects on the response time and sensitivity (Sennik et al, 2016;Luo et al, 2017;Pan et al, 2018). Chromium, one of the non-noble metals, is suggested to be suited as a dopant for improved TiO 2 sensing applications (Lyson-Sypien et al, 2012;Haidry et al, 2016;Sun et al, 2018;Monamary et al, 2019). The ionic radii of Ti 4+ (0.60 Å) and Cr 3+ (0.61 Å) is circa similar, thus Cr 3+ can replace Ti 4+ in TiO 2 lattice to form additional defects (as oxygen vacancies and interstitial Ti atoms), which can change the electronic structure of TiO 2 and transform TiO 2 into p-type.…”

Section: Introductionmentioning

confidence: 99%

Sol-gel Synthesis of TiO2 With p-Type Response to Hydrogen Gas at Elevated Temperature

Xie

Sun

et al. 2019

Front. Mater.

Self Cite

View full text Add to dashboard Cite

Titanium dioxide is considered as one of the potential candidates for high-temperature gas sensing applications due to its excellent sensitivity and stability. However, its practical use as a gas sensor under elevated conditions is limited on account of its selectivity and insufficient understanding of response conversion from n-to p-type. To this context, the present work is intended to prepare and understand the p-type response of anatase TiO 2 toward H 2 gas (20-1,000 ppm) at elevated temperature (500 • C). Sol-gel route is adopted to facilely synthesize powders containing pure and chromium (1-10 at.%) doped TiO 2 nanoparticles, which are then brushed onto substrates with already patterned inter-digitated platinum electrodes. In this work, even, the undoped TiO 2 samples showed p-type gas sensing response, which then decreased with Cr doping. However, in comparison to previously reported work, the sensing characteristics of all sensors is improved. For instance, 5 at.% Cr-TiO 2 showed high response (147), fast response and recovery (142/123s) time, and good selectivity to hydrogen against monoxide and methane. Despite better response values, the TiO 2 based samples show instability and drift in baseline resistance; such issues were not observed for Cr-doped TiO 2 samples (≥3 at.%). The powders were further analyzed by XRD, SEM, TEM, and XPS to understand the basic characteristics, p-type response and stability. Further, a plausible sensing mechanism is discussed on basis of results obtained from aforementioned techniques.

show abstract

“…Note that the optimal temperature of SnO 2 nanofiber for sensing DOP (300 • C) and 2-EH (200 • C) was very different, thus the sensor temperature was set at 260 • C as a compromise in the following tests. Note also that other experimental conditions, such as electrode structure and dimension, may also affect the sensor performance (Langer et al, 2015;Haidry et al, 2016Haidry et al, , 2019Sun et al, 2018;Fatima et al, 2019), which deserves further investigation.…”

Section: Resultsmentioning

confidence: 99%

Detection of Semi-volatile Plasticizers as a Signature of Early Electrical Fire

Jia

Chen

et al. 2019

Front. Mater.

View full text Add to dashboard Cite

Detection of characteristic species released from overheated PVC cables may enable early warning of electrical fire. This work identified the major volatile species for overheated PVC cables, and verified their potential as fire signatures with metal oxide gas sensors. Semi-volatile Dioctyl phthalate (DOP) and 2-Ethylhexanol (2-EH) were found to be ubiquitously present in the cable vapors as major species. Detection of these species and the vapors of overheated cables was accomplished with a metal oxide gas sensor. The response of the gas sensor to the cable vapors resulted mainly from DOP and 2-EH, demonstrating them as effective signature gases for overheated PVC cables. A gas sensor based on SnO 2 nanofibers was prepared with greatly enhanced response to the signature gases. Large-scale simulation tests showed that the nanofiber gas sensor could effectively detect the cable overheating at an early stage.

show abstract

Sensing mechanism of low temperature NO2 sensing with top–bottom electrode (TBE) geometry

Cited by 14 publications

References 35 publications

Cost-effective fabrication of polycrystalline TiO2 with tunable n/p response for selective hydrogen monitoring

Cost-effective fabrication of polycrystalline TiO2 with tunable n/p response for selective hydrogen monitoring

Sol-gel Synthesis of TiO2 With p-Type Response to Hydrogen Gas at Elevated Temperature

Detection of Semi-volatile Plasticizers as a Signature of Early Electrical Fire

Contact Info

Product

Resources

About