Effect of polythiophene thickness on hybrid sensor sensitivity

Abstract In recent years, hybrid structures have attracted wide consideration because they generate new very interesting properties. In this study, a hybrid gas sensor was developed using a simple fabrication process from the combination of porous silicon (PSi) and polythiophene (PTh). The study of the effect of electropolymerization rate and film thickness of PTh on the sensitivity and the stability of sensor was realized at room temperature. PSi was formed by electrochemical anodization, and it is an interesting material for sensing applications due to its high surface area. However, to avoid its degradation and to preserve its properties over the time, PSi surface was functionalized electrochemically with PTh subsequently to thermal oxidation. PTh as a conductive polymer is known for its high sensitivity and stability to environmental change. Several thicknesses of PTh have been electropolymerized onto the oxidized PSi surface to determine the best conditions for developing a sensitive and stable sensor. PTh thickness was controlled by the number of applied voltammogram cyclic. The characterizations of the different elaborated surfaces were carried out by Fourier transform infrared spectroscopy, scanning electron microscopy, cyclic voltammetry, contact angle, and secondary ion mass spectrometry. Finally, we studied the sensitivity, the response time, and the stability of PSi/PTh structures with different PTh thicknesses in the presence of CO2 gas and under cigarette smoke, by performing electrical characterizations, at room temperature.

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A p-n Heterojunction Based Pd/PdO@ZnO Organic Frameworks for High-Sensitivity Room-Temperature Formaldehyde Gas Sensor

Frontiers in Chemistry ◽

10.3389/fchem.2021.742488 ◽

2021 ◽

Vol 9 ◽

Author(s):

Faheem Ullah Khan ◽

Shahid Mehmood ◽

Shiliang Liu ◽

Wei Xu ◽

Muhammad Naeem Shah ◽

...

Keyword(s):

Gas Sensor ◽

Room Temperature ◽

Gas Sensing ◽

Metal Organic Framework ◽

Organic Pollutant ◽

High Surface ◽

High Surface Area ◽

High Sensitivity ◽

Zno Nanomaterials ◽

Sensing Performance

As formaldehyde is an extremely toxic volatile organic pollutant, a highly sensitive and selective gas sensor for low-concentration formaldehyde monitoring is of great importance. Herein, metal-organic framework (MOF) derived Pd/PdO@ZnO porous nanostructures were synthesized through hydrothermal method followed by calcination processes. Specifically, porous Pd/PdO@ZnO nanomaterials with large surfaces were synthesized using MOFs as sacrificial templates. During the calcination procedure, an optimized temperature of 500°C was used to form a stable structure. More importantly, intensive PdO@ZnO inside the material and composite interface provides lots of p-n heterojunction to efficiently manipulate room temperature sensing performance. As the height of the energy barrier at the junction of PdO@ZnO exponentially influences the sensor resistance, the Pd/PdO@ZnO nanomaterials exhibit high sensitivity (38.57% for 100 ppm) at room temperature for 1-ppm formaldehyde with satisfactory selectivity towards (ammonia, acetone, methanol, and IPA). Besides, due to the catalytic effect of Pd and PdO, the adsorption and desorption of the gas molecules are accelerated, and the response and recovery time is as small as 256 and 264 s, respectively. Therefore, this MOF-driven strategy can prepare metal oxide composites with high surface area, well-defined morphology, and satisfactory room-temperature formaldehyde gas sensing performance for indoor air quality control.

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Preparation of Polyaniline/Cu-BTC Composite and its Sensing Application for Ammonia

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.748.353 ◽

2017 ◽

Vol 748 ◽

pp. 353-357

Author(s):

Yong Jin Zou ◽

Ying Yin ◽

Hai Tao Zhang ◽

Fen Xu ◽

Li Xian Sun

Keyword(s):

Surface Area ◽

Room Temperature ◽

Gas Sensing ◽

High Surface ◽

Hydrothermal Process ◽

High Surface Area ◽

High Sensitivity ◽

Pani Composite ◽

Sensing Application ◽

Sensing Performance

In this study, a newly materials based on copper–benzene-1,3,5-tricarboxylate/polyaniline (PANI/Cu-BTC) composite was investigated for NH3 sensing. Cu-BTC was grown on the PANI a hydrothermal process. The sensing performance of as-grown product was studied for different concentrations of NH3 at room temperature. The results reveal that Cu-BTC/PANI composite exhibit high sensitivity toward NH3. The good sensing performance of the composite was attributed to high surface area and good affinity of Cu-BTC for NH3, which can act like preconcentrator for the NH3 gas sensing.

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Lawsone Derived Zn (II) and Fe (III) Metal Organic Frameworks with pH Dependent Emission for Controlled Drug Delivery

New Journal of Chemistry ◽

10.1039/d1nj01913a ◽

2021 ◽

Author(s):

Sirajunnisa P ◽

Liz Hannah George ◽

Narayanapillai Manoj ◽

Prathapan S ◽

G.S. Sailaja

Keyword(s):

Drug Delivery ◽

Porous Structure ◽

High Surface ◽

Metal Organic Frameworks ◽

High Surface Area ◽

Controlled Drug Delivery ◽

Sensing Applications ◽

Porous Carriers ◽

Metal Organic ◽

Ph Dependent

Fluorescent biocompatible porous carriers have been investigated as suitable probes for drug delivery and sensing applications owing to their intrinsic fluorescence and high surface area originating from their porous structure...

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Understanding Micro-Droplet Interface Bilayers for Developing Bioinspired Sensors

Volume 2: Mechanics and Behavior of Active Materials; Structural Health Monitoring; Bioinspired Smart Materials and Systems; Energy Harvesting ◽

10.1115/smasis2013-3134 ◽

2013 ◽

Author(s):

Guru Venkatesan ◽

Andy Sarles

Keyword(s):

Water Droplet ◽

Morphological Changes ◽

High Surface ◽

High Surface Area ◽

Material System ◽

Modes Of Operation ◽

New Class ◽

Wide Range ◽

Droplet Sizes ◽

The Stability

Droplet-based biomolecular arrays form the basis for a new class of bioinspired material system, whereby decreasing the sizes of the droplets and increasing the number of droplets can lead to higher functional density for the array. In this paper, we report on a non-microfluidic approach to form and connect nanoliter-to-femtoliter, lipid-coated aqueous droplets in oil to form micro-droplet interface bilayers (μDIBs). Two different modes of operation are reported for dispensing a wide range of droplet sizes (2–200μm radius). Due to the high surface-area-to-volume ratios of microdroplets at these length scales, droplet shrinking is prominent, which affects the stability and lifetime of the bilayer. To better quantify these effects, we measure the shrinkage rates for 8 different water droplet/oil compositions and study the effect of lipid placement and lipid type on morphological changes to μDIBs.

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The synthesis of a BiOClxBr1−x nanostructure photocatalyst with high surface area for the enhanced visible-light photocatalytic reduction of Cr(vi)

RSC Advances ◽

10.1039/c9ra10256f ◽

2020 ◽

Vol 10 (8) ◽

pp. 4763-4771 ◽

Cited By ~ 3

Author(s):

Muhammad Bilal Hussain ◽

Malik Saddam Khan ◽

Herman Maloko Loussala ◽

Muhammad Sohail Bashir

Keyword(s):

Visible Light ◽

Surface Area ◽

Room Temperature ◽

High Surface ◽

High Surface Area ◽

Photocatalytic Reduction ◽

Synthetic Process ◽

Visible Light Photocatalytic

Cr(vi) reduction is performed by BiOCl0.8Br0.2 composite produced via a facile in situ synthetic process at room temperature while making use of PVP (Mw = 10 000).

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Solid State Electronic Sensors for Detection of Carbon Dioxide

Sensors ◽

10.3390/s19183848 ◽

2019 ◽

Vol 19 (18) ◽

pp. 3848 ◽

Cited By ~ 2

Author(s):

Ami Hannon ◽

Jing Li

Keyword(s):

Carbon Dioxide ◽

Iron Oxide ◽

High Surface ◽

High Surface Area ◽

Multiwall Carbon Nanotubes ◽

High Sensitivity ◽

Space Applications ◽

Detection Range ◽

Ultra Low Power ◽

Compact Size

Detection of carbon dioxide (CO2) is very important for environmental, health, safety and space applications. We have studied novel multiwall carbon nanotubes (MWCNTs) and an iron oxide (Fe2O3) nanocomposite based chemiresistive sensor for detection of CO2 at room temperature. The sensor has been miniaturized to a chip size (1 cm × 2 cm). Good sensing performance was observed with a wide detection range of CO2 concentrations (100–6000 ppm). Structural properties of the sensing materials were characterized using Field-Emission Scanning Electron Microscopy, Fourier-Transform Infrared and Raman spectroscopies. The greatly improved sensitivity of the composite materials to CO2 can be attributed to the formation of a depletion layer at the p-n junction in an MWCNT/iron oxide heterostructure, and new CO2 gas molecules adhere to the high surface area of MWCNTs due to the concentration gradient. The test results showed that the CO2 sensor possesses fast response, compact size, ultra-low power consumption, high sensitivity and wide dynamic detection range.

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An Efficient Electrochemical Sensor Driven by Hierarchical Hetero-Nanostructures Consisting of RuO2 Nanorods on WO3 Nanofibers for Detecting Biologically Relevant Molecules

Sensors ◽

10.3390/s19153295 ◽

2019 ◽

Vol 19 (15) ◽

pp. 3295 ◽

Cited By ~ 1

Author(s):

Hyerim Lee ◽

Yeomin Kim ◽

Areum Yu ◽

Dasol Jin ◽

Ara Jo ◽

...

Keyword(s):

Tungsten Trioxide ◽

High Surface ◽

High Surface Area ◽

High Sensitivity ◽

Annealing Process ◽

Electrochemical Sensing ◽

Biologically Relevant ◽

Sensing Platform ◽

Thermal Annealing Process ◽

Biologically Relevant Molecules

By means of electrospinning with the thermal annealing process, we investigate a highly efficient sensing platform driven by a hierarchical hetero-nanostructure for the sensitive detection of biologically relevant molecules, consisting of single crystalline ruthenium dioxide nanorods (RuO2 NRs) directly grown on the surface of electrospun tungsten trioxide nanofibers (WO3 NFs). Electrochemical measurements reveal the enhanced electron transfer kinetics at the prepared RuO2 NRs-WO3 NFs hetero-nanostructures due to the incorporation of conductive RuO2 NRs nanostructures with a high surface area, resulting in improved relevant electrochemical sensing performances for detecting H2O2 and L-ascorbic acid with high sensitivity.

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Graphene-based Nanomaterials for Fabrication of ‘Pesticide’ Electrochemical Sensors

Current Graphene Science ◽

10.2174/2452273203666191007143008 ◽

2020 ◽

Vol 3 (1) ◽

pp. 26-40

Author(s):

Manorama Singh ◽

Smita R. Bhardiya ◽

Fooleswar Verma ◽

Vijai K. Rai ◽

Ankita Rai

Keyword(s):

Electrochemical Sensors ◽

Hybrid Composites ◽

High Surface ◽

High Surface Area ◽

High Sensitivity ◽

Sensor Technology ◽

Hybrid Functional ◽

Suitable Material ◽

Functional Composites

At present, graphene is one of the most up-to-date materials and it can be applied for various energy conversion devices and sensor technology. In this review article, our main focus is to summarize the role of graphene and its modified surface leading to develop hybrid nanomaterials and its applications in fabrication of pesticide sensor. Graphene based materials demonstrate exclusive electrochemical and optical properties as well as compatibility to absorb a variety of bio-molecules through π-π stacking interaction and/or electrostatics interaction, which make them ideal material to be employed in sensor application. The role of graphene is very crucial in preparing different unique and desirable hybrid functional composites along with nanoparticles, redox mediators, conducting polymers etc. to improve the performance of the sensors. Therefore, they can be easily used as a suitable material applying in fabrication of electrochemical sensors/ biosensors for the detection of organophosphorous and carbamate pesticides. A number of most recent reported works were discussed in which graphene-based hybrid composites show high sensitivity, good catalytic activity, selectivity towards the determination of pesticide either enzymatically or nonenzymatically. The properties of graphene (exceptional charge transport, thermal, optical, mechanical, high surface area, large pore volume and size, an opened ordered structure) play an important role in pesticide detection.

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GROWTH, MORPHOLOGY, INTERFACIAL EFFECTS AND CATALYTIC PROPERTIES OF Au ON TiO2

Surface Review and Letters ◽

10.1142/s0218625x01000884 ◽

2001 ◽

Vol 08 (01n02) ◽

pp. 73-93 ◽

Cited By ~ 121

Author(s):

F. COSANDEY ◽

T. E. MADEY

Keyword(s):

Surface Science ◽

Ultrathin Films ◽

Room Temperature ◽

Catalytic Properties ◽

High Surface ◽

High Surface Area ◽

Model System ◽

Growth Morphology ◽

Oxide Substrate ◽

Planar Films

We survey recent studies and present new data on the growth, interactions, structure and chemistry of gold deposited on TiO 2(110) surfaces. The noble metal Au on TiO 2(110) is a model system for weak interaction of a metal with an oxide substrate; it is also of interest because Au on TiO 2 has unusually high activity as a catalyst for CO oxidation at room temperature. In this review, we present results on the growth of ultrathin films of Au on TiO 2(110), as well as the morphology, interface formation, epitaxy, structure and electronic properties of Au on TiO 2 single crystal and planar films. The results are compared to studies of Au on high-surface-area TiO 2 catalysts in an attempt to bridge the gap between surface science experiments and the high pressure conditions of catalyst operation.

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