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Journal ArticleDOI

Fabrication of Microsensor for Detection of Low-Concentration Formaldehyde Gas in Formalin-Treated Fish

01 Dec 2020-IEEE Transactions on Electron Devices (Institute of Electrical and Electronics Engineers (IEEE))-Vol. 67, Iss: 12, pp 5710-5716
TL;DR: In this paper, an ultrafast direct laser patterning technique was used to fabricate a low-cost microsensor and its application for formaldehyde detection was reported, where the patterns of microheater and interdigitated electrodes (IDEs) were realized using laser micromachining techniques by ablation of gold thin film on alumina substrate.
Abstract: Here, an ultrafast direct laser patterning technique to fabricate a low-cost microsensor and its application for formaldehyde detection are reported. The patterns of microheater and interdigitated electrodes (IDEs) were realized using laser micromachining techniques by ablation of gold thin film on alumina substrate. The thin film of gold microheater showed good stability up to 300 °C with a fast response time of 80 s and temperature coefficient of resistance (TCR) was calculated as $1.37\times 10^{-{3}}/^{\circ }\text{C}$ . Moreover, gold microheater exhibited long-term reliability under self-heating mode with a negligible resistance drift $^{-{1}}$ ) to formaldehyde even to detect sub-ppm concentrations with fast response (32 s) and recovery kinetics (72 s). Moreover, the microsensor was also used on-site rapid screening for the detection and quantification of formaldehyde concentration in formalin-treated fish sample.
Citations
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Journal ArticleDOI
TL;DR: In this article, a highly sensitive and selective gas sensor for detecting formaldehyde is reported based on SnO2/ZnO heterospheres designed by atomic layer deposition (ALD).
Abstract: Heterostructures of metal oxide semiconductors have a great promise for chemical gas sensors due to the peculiar properties at the heterointerface. In this work, a highly sensitive and selective gas sensor for detecting formaldehyde is reported based on SnO2/ZnO heterospheres designed by atomic layer deposition (ALD). The electronic properties at the SnO2/ZnO heterointerface can be modulated by optimizing the loading of ZnO through changing ALD cycles. Gas sensing tests indicate that the ZnO ALD significantly improved the sensor properties including higher responses, faster response-recovery dynamics and better selectivity. The response of the SnO2/ZnO sensor to 1 ppm formaldehyde (Ra/Rg = 9.7) shows 4 times enhancement compared to pristine SnO2 at a working temperature of 200 °C. ZnO ALD of 10 cycles leads to the best response and recovery dynamics (12 and 24 s), and that of 15 ALD cycles results in the highest response (Ra/Rg = 38.2) to 20 ppm formaldehyde. The SnO2/ZnO sensor also registers a low detection limit of 70 ppb, which allows for reliable detection of sub-ppm formaldehyde. The remarkable sensor performances indicate the ALD surface engineering is promising for the design of new materials for reliable detection of harmful molecules.

87 citations

Journal ArticleDOI
TL;DR: In this article, Fe2O3-sensitized SnO2 nanosheets are designed via atomic layer deposition (ALD) to realize high performance formaldehyde detection, by varying the ALD cycles, the influence of different Fe 2O3 loading on the sensing performance of SnO 2 nanOSheets is revealed.
Abstract: Metal oxide semiconductor (MOS) nanostructures have been widely explored for formaldehyde sensors. The low surface chemical and electronic properties of pure MOS, however, greatly limits the sensor functions. In this work, Fe2O3-sensitized SnO2 nanosheets are designed via atomic layer deposition (ALD) to realize high performance formaldehyde detection. By varying the ALD cycles, the influence of different Fe2O3 loading on the sensing performance of SnO2 nanosheets is revealed. It is found that Fe2O3 ALD can greatly boost the sensing performance and the SnO2 nanosheets with 20 Fe2O3 ALD cycles exhibits the best response (Ra/Rg = 4.5) and fast response and recovery dynamics (9 and 34 s) to 20 ppm formaldehyde at a relative low temperature of 220 °C. The sensor based on SnO2/Fe2O3 also displays good selectivity to formaldehyde as well as the reliable stability and low limit of detection (LOD). This work will shed some light to design efficient MOS heterostructures for detection of formaldehyde.

37 citations

Journal ArticleDOI
TL;DR: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good performance as discussed by the authors .
Abstract: The significance of two-dimensional (2D) materials including graphene, and transition metal dichalcogenides has been escalating in gas sensor technology owing to detection of gases at room temperature (RT) and good...

1 citations

Journal ArticleDOI
TL;DR: In this paper , a research on the evaluation of adolescent lower limb posture correction based on collaborative filtering and microsensors is carried out, which simplifies the existing human body posture monitoring model and establishes a human body model with four degrees of freedom of the lower limbs.
Abstract: Automatic monitoring of physical activity provides reliable data support for the maintenance of people's physical health and provides more scientific data for studying the relationship between physical activity and disease. In this article, a research on the evaluation of adolescent lower limb posture correction based on collaborative filtering and microsensors is carried out. Aiming at the problem that the human body posture monitoring system needs multiple nodes, this article simplifies the existing human body posture monitoring model and establishes a human body model with four degrees of freedom of the lower limbs. On this basis, the micro-sensor assembly scheme and monitoring node layout scheme for obtaining model description parameters are determined. Methods such as collaborative filtering and support vector machines are used in the process of sensor data processing and correction effect evaluation. Finally, this article uses the constructed human body posture monitoring system to carry out the recognition test of the specific posture of the human body. The experimental results show that the evaluation scheme can effectively monitor and evaluate the effect of lower limb posture correction in adolescents.

1 citations

Journal ArticleDOI
TL;DR: In this article , density functional theory (DFT) analyzes the electronic structure of sensing materials and the adsorption energy of butyl acetate, and the effects of Ni element doping, oxygen vacancy constructions, and NiO quantum dot modifications on the modulation of the electronic structures of ZnO and on the ad-hoc energy of Butyl Acetate are investigated in detail.
References
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Journal ArticleDOI
TL;DR: Concentrations of 0.4 ppm in manufactured homes as targeted by the Department of Housing and Urban Development may not be adequate to protect occupants from discomfort and from acute effects of HCHO exposure.
Abstract: This paper explores the dose-response relation between formaldehyde (HCHO) concentration and reported health complaints (eye irritation, nose/throat irritation, headaches and skin rash) of nearly 2,000 residents living in 397 mobile and 494 conventional homes. The study analyzes the effects of HCHO concentration, age and sex of respondent, and smoking behavior on each of the four health effects. The results demonstrate a positive dose-response relation between HCHO concentration and reported health complaints, with reported health complaints demonstrated at HCHO concentrations of 0.1 ppm and above. Concentrations of 0.4 ppm in manufactured homes as targeted by the Department of Housing and Urban Development (HUD), may not be adequate to protect occupants from discomfort and from acute effects of HCHO exposure.

70 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...FORMALDEHYDE is one of the most important indoor pollutants, which is produced either by thermal or chemical decomposition of many day-to-day used articles [1]–[3]....

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Journal ArticleDOI
TL;DR: In this paper, mesoporous SnO2 fibers are used to fabricate a bare sensor and then the sensor is functionalized with Pd nanodots by a facile dipping-annealing process.
Abstract: The permissible limitation of formaldehyde (HCHO) is 80 ppb in an indoor environment. Hence, the rapid real-time monitoring of trace HCHO is urgent and faced as a great challenge by gas sensors based on semiconducting metal oxides. To enhance the HCHO sensing performance of gas sensors, mesoporous SnO2 fibers are used to fabricate a bare SnO2 sensor and then the sensor is functionalized with Pd nanodots by a facile dipping–annealing process. The obtained Pd-functionalized SnO2 sensor exhibits a very high response to HCHO, ultralow detection limit (50 ppb), excellent sensor selectivity over other reducing gases, and short response and recovery time to 100 ppb HCHO (53 s and 103 s, respectively) at a low working temperature of 190 °C. Herein, the Pd nanodots loaded onto SnO2 fibers serve as sensitizers or promoters, increasing the amount of adsorbates as well as molecule–ion conversion rate and simultaneously providing a new catalytic oxidization pathway of HCHO (HCHO → [CH2O]n (POM) → HCOOH → CO2 + H2O) accompanied with a promotion in the electron transfer rate, and thus improving HCHO sensing performance. The combination of the SnO2 mesoporous structure and catalytic activity of the Pd nanodots loaded could give us a very attractive sensing behavior for applications as real-time monitoring gas sensors with rapid response speed.

62 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...When the SnO2 sensor was exposed to a reducing gas (HCHO), the adsorbed oxygen ions (O2 , O − or O2 ) at the SnO2 grains boundaries are removed for oxidizing with HCHO molecules, and electrons were transferred back into the conduction band of the SnO2, leading to increase conductivity of SnO2 materials [38]....

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Journal ArticleDOI
TL;DR: In this article, the sensing behavior of tin dioxide nanowires has been tested under different concentrations of formaldehyde (HCHO), showing a high sensitivity and very short response and recovery times even at low operating temperatures (130°C).

60 citations


"Fabrication of Microsensor for Dete..." refers methods in this paper

  • ...To obtain the desired concentration of formaldehyde and other volatile organic compounds (VOCs), a predetermined amount of liquid analyte sources were injected into the test chamber via a micropipette [25], [26]....

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Journal ArticleDOI
TL;DR: In this article, a hierarchical structured TiO 2 nano-tubes were prepared following a two-step method: the highly ordered uniform TiO2 nanotube arrays were first grown by the conventional electrochemical anodization of the Ti metal sheet followed by mechanical milling of the as-fabricated TiO 1 nanotubes arrays.

52 citations


"Fabrication of Microsensor for Dete..." refers methods in this paper

  • ...The sensor response (S) to a test gas was defined as the relative percentage change of the resistance, calculated as, response (%) = [((Rg − Ra)/Ra)×100] [29], where Rg and Ra denote the resistance of the sensor when exposed to target gas and ambient air, respectively....

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Journal ArticleDOI
TL;DR: In this article, a novel gas sensor based on Ag nanoparticle-doped WO3 nanosheets with various doping levels was successfully fabricated via a two-step process that included a facile acid-precipitation method followed by a dipping route.

41 citations


"Fabrication of Microsensor for Dete..." refers background in this paper

  • ...which demonstrates the excellent reproducibility and stability of the sensor [32]....

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