Three-dimensional platinum nanoparticle-based bridges for ammonia gas sensing

AbstractThis study demonstrates the fabrication of self-aligning three-dimensional (3D) platinum bridges for ammonia gas sensing using gas-phase electrodeposition. This deposition scheme can guide charged nanoparticles to predetermined locations on a surface with sub-micrometer resolution. A shutter-free deposition is possible, preventing the use of additional steps for lift-off and improving material yield. This method uses a spark discharge-based platinum nanoparticle source in combination with sequentially biased surface electrodes and charged photoresist patterns on a glass substrate. In this way, the parallel growth of multiple sensing nodes, in this case 3D self-aligning nanoparticle-based bridges, is accomplished. An array containing 360 locally grown bridges made out of 5 nm platinum nanoparticles is fabricated. The high surface-to-volume ratio of the 3D bridge morphology enables fast response and room temperature operated sensing capabilities. The bridges are preconditioned for ~ 24 h in nitrogen gas before being used for performance testing, ensuring drift-free sensor performance. In this study, platinum bridges are demonstrated to detect ammonia (NH3) with concentrations between 1400 and 100 ppm. The sensing mechanism, response times, cross-sensitivity, selectivity, and sensor stability are discussed. The device showed a sensor response of ~ 4% at 100 ppm NH3 with a 70% response time of 8 min at room temperature.

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A Review on Biosensors and Recent Development of Nanostructured Materials-Enabled Biosensors

Sensors ◽

10.3390/s21041109 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1109

Author(s):

Varnakavi. Naresh ◽

Nohyun Lee

Keyword(s):

High Surface ◽

Three Dimensional ◽

Biological Response ◽

Volume Ratio ◽

Recent Decade ◽

Disease Diagnosis ◽

Electrical Signal ◽

Detection Sensitivity ◽

Wide Range ◽

Color Tunability

A biosensor is an integrated receptor-transducer device, which can convert a biological response into an electrical signal. The design and development of biosensors have taken a center stage for researchers or scientists in the recent decade owing to the wide range of biosensor applications, such as health care and disease diagnosis, environmental monitoring, water and food quality monitoring, and drug delivery. The main challenges involved in the biosensor progress are (i) the efficient capturing of biorecognition signals and the transformation of these signals into electrochemical, electrical, optical, gravimetric, or acoustic signals (transduction process), (ii) enhancing transducer performance i.e., increasing sensitivity, shorter response time, reproducibility, and low detection limits even to detect individual molecules, and (iii) miniaturization of the biosensing devices using micro-and nano-fabrication technologies. Those challenges can be met through the integration of sensing technology with nanomaterials, which range from zero- to three-dimensional, possessing a high surface-to-volume ratio, good conductivities, shock-bearing abilities, and color tunability. Nanomaterials (NMs) employed in the fabrication and nanobiosensors include nanoparticles (NPs) (high stability and high carrier capacity), nanowires (NWs) and nanorods (NRs) (capable of high detection sensitivity), carbon nanotubes (CNTs) (large surface area, high electrical and thermal conductivity), and quantum dots (QDs) (color tunability). Furthermore, these nanomaterials can themselves act as transduction elements. This review summarizes the evolution of biosensors, the types of biosensors based on their receptors, transducers, and modern approaches employed in biosensors using nanomaterials such as NPs (e.g., noble metal NPs and metal oxide NPs), NWs, NRs, CNTs, QDs, and dendrimers and their recent advancement in biosensing technology with the expansion of nanotechnology.

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Effect of current density on the porous silicon preparation as gas sensors**

Journal of the Mechanical Behavior of Materials ◽

10.1515/jmbm-2021-0027 ◽

2021 ◽

Vol 30 (1) ◽

pp. 257-264

Author(s):

Muna H. Kareem ◽

Adi M. Abdul Hussein ◽

Haitham Talib Hussein

Keyword(s):

Porous Silicon ◽

Gas Sensors ◽

Current Density ◽

Room Temperature ◽

Low Cost ◽

High Surface ◽

Volume Ratio ◽

Etching Time ◽

Force Microscopy ◽

Materials Used

Abstract In this study, porous silicon (PSi) was used to manufacture gas sensors for acetone and ethanol. Samples of PSi were successfully prepared by photoelectrochemical etching and applied as an acetone and ethanol gas sensor at room temperature at various current densities J= 12, 24 and 30 mA/cm2 with an etching time of 10 min and hydrofluoric acid concentration of 40%. Well-ordered n-type PSi (100) was carefully studied for its chemical composition, surface structure and bond configuration of the surface via X-ray diffraction, atomic force microscopy, Fourier transform infrared spectroscopy and photoluminescence tests. Results showed that the best sensitivity of PSi was to acetone gas than to ethanol under the same conditions at an etching current density of 30 mA/cm2, reaching about 2.413 at a concentration of 500 parts per million. The PSi layers served as low-cost and high-quality acetone gas sensors. Thus, PSi can be used to replace expensive materials used in gas sensors that function at low temperatures, including room temperature. The material has an exceptionally high surface-to-volume ratio (increasing surface area) and demonstrates ease of fabrication and compatibility with manufacturing processes of silicon microelectronics.

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A Review of Carbon Nanotubes-Based Gas Sensors

Journal of Sensors ◽

10.1155/2009/493904 ◽

2009 ◽

Vol 2009 ◽

pp. 1-24 ◽

Cited By ~ 255

Author(s):

Yun Wang ◽

John T. W. Yeow

Keyword(s):

Carbon Nanotubes ◽

Gas Sensors ◽

Gas Sensing ◽

Low Cost ◽

High Surface ◽

Hollow Structure ◽

Volume Ratio ◽

Fast Response ◽

Sensing Technology ◽

Structure Of Nanomaterials

Gas sensors have attracted intensive research interest due to the demand of sensitive, fast response, and stable sensors for industry, environmental monitoring, biomedicine, and so forth. The development of nanotechnology has created huge potential to build highly sensitive, low cost, portable sensors with low power consumption. The extremely high surface-to-volume ratio and hollow structure of nanomaterials is ideal for the adsorption of gas molecules. Particularly, the advent of carbon nanotubes (CNTs) has fuelled the inventions of gas sensors that exploit CNTs' unique geometry, morphology, and material properties. Upon exposure to certain gases, the changes in CNTs' properties can be detected by various methods. Therefore, CNTs-based gas sensors and their mechanisms have been widely studied recently. In this paper, a broad but yet in-depth survey of current CNTs-based gas sensing technology is presented. Both experimental works and theoretical simulations are reviewed. The design, fabrication, and the sensing mechanisms of the CNTs-based gas sensors are discussed. The challenges and perspectives of the research are also addressed in this review.

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Nanomaterial-based gas sensors used for breath diagnosis

Journal of Materials Chemistry B ◽

10.1039/c9tb02518a ◽

2020 ◽

Vol 8 (16) ◽

pp. 3231-3248 ◽

Cited By ~ 8

Author(s):

Xinyuan Zhou ◽

Zhenjie Xue ◽

Xiangyu Chen ◽

Chuanhui Huang ◽

Wanqiao Bai ◽

...

Keyword(s):

Physicochemical Properties ◽

Gas Sensors ◽

Active Sites ◽

Gas Sensing ◽

High Surface ◽

Volume Ratio ◽

Sensing Applications ◽

Enormous Number

Gas-sensing applications commonly use nanomaterials (NMs) because of their unique physicochemical properties, including a high surface-to-volume ratio, enormous number of active sites, controllable morphology, and potential for miniaturisation.

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Nanostructured ZnO/Ag Film Prepared by Magnetron Sputtering Method for Fast Response of Ammonia Gas Detection

Molecules ◽

10.3390/molecules25081899 ◽

2020 ◽

Vol 25 (8) ◽

pp. 1899 ◽

Cited By ~ 1

Author(s):

Yiran Zheng ◽

Min Li ◽

Xiaoyan Wen ◽

Ho-Pui Ho ◽

Haifei Lu

Keyword(s):

Magnetron Sputtering ◽

Thermal Annealing ◽

Physical Vapor Deposition ◽

Gas Sensing ◽

Volume Ratio ◽

Fast Response ◽

Gas Detection ◽

Zno Films ◽

Zno Film ◽

Ammonia Gas

Possessing a large surface-to-volume ratio is significant to the sensitive gas detection of semiconductor nanostructures. Here, we propose a fast-response ammonia gas sensor based on porous nanostructured zinc oxide (ZnO) film, which is fabricated through physical vapor deposition and subsequent thermal annealing. In general, an extremely thin silver (Ag) layer (1, 3, 5 nm) and a 100 nm ZnO film are sequentially deposited on the SiO2/Si substrate by a magnetron sputtering method. The porous nanostructure of ZnO film is formed after thermal annealing contributed by the diffusion of Ag among ZnO crystal grains and the expansion of the ZnO film. Different thicknesses of the Ag layer help the formation of different sizes and quantities of hollows uniformly distributed in the ZnO film, which is demonstrated to hold superior gas sensing abilities than the compact ZnO film. The responses of the different porous ZnO films were also investigated in the ammonia concentration range of 10 to 300 ppm. Experimental results demonstrate that the ZnO/Ag(3 nm) sensor possesses a good electrical resistance variation of 85.74% after exposing the sample to 300 ppm ammonia gas for 310 s. Interestingly, a fast response of 61.18% in 60 s for 300 ppm ammonia gas has been achieved from the ZnO/Ag(5 nm) sensor, which costs only 6 s for the response increase to 10%. Therefore, this controllable, porous, nanostructured ZnO film maintaining a sensitive gas response, fabricated by the physical deposition approach, will be of great interest to the gas-sensing community.

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Novel Zinc-Based Infinite Coordination Polymer for Highly Selective Ammonia Gas Sensing at Room Temperature

Bulletin of the Chemical Society of Japan ◽

10.1246/bcsj.20200132 ◽

2020 ◽

Vol 93 (9) ◽

pp. 1070-1073

Author(s):

Yuming Zhao ◽

Lei Shao ◽

Linlin Li ◽

Sha Wang ◽

Guoshuai Song ◽

...

Keyword(s):

Coordination Polymer ◽

Room Temperature ◽

Gas Sensing ◽

Ammonia Gas

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Ammonia Gas Detection by Tannic Acid Functionalized and Reduced Graphene Oxide at Room Temperature

Journal of Nanomaterials ◽

10.1155/2014/497384 ◽

2014 ◽

Vol 2014 ◽

pp. 1-6 ◽

Cited By ~ 40

Author(s):

Sweejiang Yoo ◽

Xin Li ◽

Yuan Wu ◽

Weihua Liu ◽

Xiaoli Wang ◽

...

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Gas Sensor ◽

Tannic Acid ◽

Room Temperature ◽

Gas Sensing ◽

High Sensitivity ◽

Gas Detection ◽

Ammonia Gas ◽

Reduced Graphene

Reduced graphene oxide (rGO) based chemiresistor gas sensor has received much attention in gas sensing for high sensitivity, room temperature operation, and reversible. Here, for the first time, we present a promising chemiresistor for ammonia gas detection based on tannic acid (TA) functionalized and reduced graphene oxide (rGOTA functionalized). Green reductant of TA plays a major role in both reducing process and enhancing the gas sensing properties ofrGOTA functionalized. Our results showrGOTA functionalizedonly selective to ammonia with excellent respond, recovery, respond time, and recovery times.rGOTA functionalizedelectrical resistance decreases upon exposure to NH3where we postulated that it is due to n-doping by TA and charge transfer betweenrGOTA functionalizedand NH3through hydrogen bonding. Furthermore,rGOTA functionalizedhinders the needs for stimulus for both recovery and respond. The combination of greener sensing material and simplicity in overall sensor design provides a new sight for green reductant approach of rGO based chemiresistor gas sensor.

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