High Ammonia Sensitive Semiconductor Gas Sensors with Double‐Layer Structure and Interface Electrodes

Takao, Yuji; Miyazaki, K.; Shimizu, Yasuhiro; Egashira, Makoto

doi:10.1149/1.2054836

Cited by 117 publications

(47 citation statements)

References 2 publications

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“…Various bulk-heterojunction photovoltaic devices have been made in recent years using polymer composites [1] or conjugated polymers with fullerenes. [2,4±6] Moreover, polymers have been blended with CdSe nanoparticles to create hybrid solar cells.…”

Section: Methodsmentioning

confidence: 99%

Enhanced Sensitivity of a Gas Sensor Incorporating Single‐Walled Carbon Nanotube–Polypyrrole Nanocomposites

Jeong

Hwang³

et al. 2004

Advanced Materials

499

188

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Metal oxides have often been utilized for commercial gassensor materials.[1] In spite of their high sensitivity, their high power consumption due to high resistance has been a serious drawback. Conducting polymers have also been tried, since they operate at room temperature and have good sensitivity and reproducibility. However, the effects of humidity and degradation by ultraviolet irradiation, in particular, have hindered further practical applications. [2] Recently, carbon nanotube (CNT)-based gas sensors have received a great deal of attention. Nanosized CNT-based gas sensors of the field-effect-transistor type have superb sensitivity at room temperature due to a drastic change in the electrical conductivity upon the adsorption of various gases. [3,4] Despite such advantages, however, their application is still limited by a long recovery time and a complex fabrication process. In particular, the single-walled carbon nanotubes (SWNTs) used for gas sensors must be semiconducting.[5] However, the presence of both metallic and semiconducting carbon nanotubes in conventional powder samples reduces the reproducibility and/or yield of the devices. The issue here is to introduce an easy fabrication process of gas sensors whilst still retaining high sensitivity. To meet this criterion, we fabricated a gas sensor from a nanocomposite by polymerizing pyrrole monomer with SWNTs. Polypyrrole (Ppy) was prepared by a simple and straightforward in situ chemical polymerization of pyrrole mixed with SWNTs, and the sensor electrodes were formed by spin-casting SWNT/Ppy onto pre-patterned electrodes. Ppy was uniformly coated on the wall of the SWNTs to increase the specific surface area. The measured resistivity was greatly reduced due to the presence of the conductive SWNT network, whereas the specific surface area was increased about threefold. The sensitivity of the gas sensor fabricated with the SWNT/Ppy nanocomposite towards NO 2 gas, as measured by a direct voltage divider at room temperature, was very high and similar to that of the fabricated SWNTs alone.[3] Figure 1 shows the typical field-emission scanning electron microscope (FESEM) images of the Ppy, SWNTs, and SWNT/ Ppy nanocomposite formed by a simple in situ chemical polymerization. Pure Ppy synthesized without SWNTs (Fig. 1a) shows a typical granular morphology. The granule size of the pure Ppy is about 0.2±0.3 lm. The purified SWNTs shown in Figure 1b are entangled and crosslinked with a typical bundle diameter of 20 nm. The pyrrole monomer becomes anchored to the carbon nanotube walls during polymerization, covering them completely, as shown in Figure 1c. The inset of this figure shows the shape of the electrodes formed on the substrate. The two electrodes are separated by 500 lm. The specific surface areas of Ppy, SWNTs, and SWNT/Ppy nanocomposite were 23, 100, 65 m 2 g ±1 , respectively. [6] The surface area of the COMMUNICATIONS

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Section: Methodsmentioning

confidence: 99%

Enhanced Sensitivity of a Gas Sensor Incorporating Single‐Walled Carbon Nanotube–Polypyrrole Nanocomposites

Jeong

Hwang³

et al. 2004

Advanced Materials

499

188

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“…It is found that although all gas molecules can influence the electronic structure of AGNRs, only NH 3 molecule adsorption can modify the conductance of AGNRs remarkably by acting as donors while other gas molecules have little effect on conductance. This property can be utilized to detect NH 3 out of other common gases, which is requisite and significant in industrial, medical, and living environments [32].…”

Section: Introductionmentioning

confidence: 99%

Adsorption of Gas Molecules on Graphene Nanoribbons and Its Implication for Nanoscale Molecule Sensor

et al. 2008

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We have studied the adsorption of gas molecules (CO, NO, NO 2 , O 2 , N 2 , CO 2 , and NH 3 ) on graphene nanoribbons (GNRs) using first principles methods. The adsorption geometries, adsorption energies, charge transfer, and electronic band structures are obtained. We find that the electronic and transport properties of the GNR with armchair-shaped edges are sensitive to the adsorption of NH 3 and the system exhibits n-type semiconducting behavior after NH 3 adsorption.Other gas molecules have little effect on modifying the conductance of GNRs. Quantum transport calculations further indicate that NH 3 molecules can be detected out of these gas molecules by GNR based sensor.

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“…When the sensor material is exposed to vapors of ammonia, the superficial reactions of NH 3 molecules with the oxygen species caused more electrons to return to the conduction band because ammonia acting as the electron donor. The surface reactions between the NH 3 and the sensor material can be described as follows [18][19][20][21] where O − (ads), NO 2 − (ads), and NO 3 − (ads) represent negatively charged chemisorbed species, and e − free electrons available for electrical conduction. The relations means that when the sensor is exposed to NH 3 containing gas, electrons trapped by the adsorptive states will be released, leading to a decrease in sensor resistance, as experimentally observed (Fig.…”

Section: Resultsmentioning

confidence: 99%

ROOM-TEMPERATURE NH3 GAS SENSORS BASED ON HETEROSTRUCTURES PbS/CdS

Prokopenko¹,

Gunja²,

Makhno³

et al. 2017

Him. Fiz. Tehnol. Poverhni

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High Ammonia Sensitive Semiconductor Gas Sensors with Double‐Layer Structure and Interface Electrodes

Abstract: firms the applicability Li § gel electrolyte for optical devices. In addition, this electrolyte has a very wide electrochemical stability window (i.e., ranging from 0 to about 5 V vs. Li, see Fig. 9), which gives assurance of an unusual 1657 (1990).

Cited by 117 publications

References 2 publications

Enhanced Sensitivity of a Gas Sensor Incorporating Single‐Walled Carbon Nanotube–Polypyrrole Nanocomposites

Enhanced Sensitivity of a Gas Sensor Incorporating Single‐Walled Carbon Nanotube–Polypyrrole Nanocomposites

Adsorption of Gas Molecules on Graphene Nanoribbons and Its Implication for Nanoscale Molecule Sensor

ROOM-TEMPERATURE NH3 GAS SENSORS BASED ON HETEROSTRUCTURES PbS/CdS

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