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.
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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
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
01 Jan 2023-Journal of Materials Chemistry C. Materials for Optical, Magnetic and Electronic Devices
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
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
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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TL;DR: In this paper, flat-type coplanar gas sensor arrays of ZnO with different MnO2 additive concentration were fabricated by a combination of screen-printing technology and solution growth process.
Abstract: Nanostructured flat-type coplanar gas sensor arrays of ZnO with different MnO2 additive concentration were fabricated by a combination of screen-printing technology and solution growth process. The morphologies and crystal structures were characterized by X-ray diffraction (XRD) and field-emission scanning electron microscopy (FESEM). The results showed that ZnO nanostructures were induced on the surface of gas sensor arrays through the solution growth process. The nanostructures were composed of nanowalls and nanosheets with the thickness of about 50–200 nm and length of about 1–2 μm. The resistance–temperature characteristic and the response to formaldehyde revealed that the solution growth process could effectively control the morphologies, change the aspect ratio of ZnO nanostructures and significantly improve the response of gas sensor arrays. In addition, the response to formaldehyde of ZnO sensors with 0.5 wt% and 1.0 wt% MnO2 additive was higher than that of pure ZnO sensor.
120 citations
TL;DR: A review of portable, high sensitive and real-time formaldehyde analyzers can be found in this article, where the authors report the developments made over the last decade toward the realization of portable and high sensitive realtime analyzers.
Abstract: Formaldehyde is a colorless gas emitted into the indoor environment by furniture and many other sources. In 2006, International Agency for Research on Cancer (IARC) classified formaldehyde as carcinogen to humans even at low concentrations. The World Health Organization (WHO) determined a guideline value of 82 ppb (parts per billion). Standard analysis based on sampling and then gas chromatography (GC) or high-performance liquid chromatography (HPLC) methods are off-line methods and are considered to be time-consuming and cumbersome, in addition to their large sizes, weights, high cost in terms of both equipment and consumables. This review reports the developments made over the last decade toward the realization of portable, high sensitive and real-time formaldehyde analyzers.
102 citations
"Fabrication of Microsensor for Dete..." refers background in this paper
...Hence, detection of formaldehyde at a low concentration level is highly important for the safety of our health [10]....
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01 Jan 2003
TL;DR: In this paper, the status of micromachining with femtosecond pulses is reviewed for a variety of materials and a comparison made with other solid-state lasers, and an outlook for developments in this area is presented.
Abstract: Femtosecond lasers currently show much promise as potential sources of choice in a number of laser micromachining applications, including biomedicine, photonics and semiconductors. The status of micromachining with femtosecond pulses is reviewed for a variety of materials and a comparison made with other solid-state lasers. An outlook for developments in this area is presented.
98 citations
"Fabrication of Microsensor for Dete..." refers background in this paper
...heaters and microsensors on alumina and flexible substrates [20]–[22]....
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TL;DR: A formaldehyde sensor fabricated by coating polyethyleneimine functionalized chitosan nanofiber-net-binary structured layer on quartz crystal microbalance (QCM) presented rapid response and low detection limit at room temperature.
87 citations
"Fabrication of Microsensor for Dete..." refers methods in this paper
...The concentration of the formaldehyde in the test chamber was calculated in ppm according to the following equation [27], [28]:...
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TL;DR: In this article, a fabrication process for high-temperature MEMS microhotplates that uses sputtered molybdenum as a conductive material is presented, and the overall performances of the microhotplate are tested, with regard to power consumption, temperature uniformity and dynamic behavior.
Abstract: This paper presents a fabrication process for high-temperature MEMS microhotplates that uses sputtered molybdenum as a conductive material. Molybdenum has a high melting point (2693 °C, bulk) and is simpler to deposit and pattern in larger series than platinum. Molybdenum is sensitive to oxidation above 300 °C, so during fabrication it is protected by PECVD silicon oxide. The electrical resistivity is linear with the temperature up to 700 °C at least. Molybdenum microhotplate has a higher maximum operating temperature than platinum which is demonstrated by the observation of the boiling of barium carbonate (BaCO3) microcrystals at 1360 °C. Annealing at 1100 °C is effective in extending the operating range. The molybdenum microhotplate performs far better than platinum also in terms of long-term resistance drift. The material properties of the sputtered molybdenum are studied and the overall performances of the microhotplate are tested, with regard to power consumption, temperature uniformity and dynamic behavior.
82 citations
"Fabrication of Microsensor for Dete..." refers background in this paper
...Over the past few decades, various metals and nonmetals, such as platinum [14], gold [15], polysilicon [16], molybdenum [17], nichrome [18], and tungsten [19], are being used as a microheater material for the production of metal oxide gas sensors and are fabricated using conventional lithographybased microfabrication techniques....
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