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In this article, polythiophene (PTh) and a polythiophene/molybdenum oxide nanocomposite (PTh/MoO3) were synthesized by an in-situ chemical oxidative method. The successful synthesis of both the materials was confirmed by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission el...
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... the characteristic peaks of PTh observed in its spectrum ( In the spectrum of the MoO3 NPs (Fig. 1b), three major peaks were observed at 996.2 cm -1 , 860.2 cm -1 , and 501.1 cm -1 due to stretching vibrations of the terminal M=O bond, Mo₋ O₋ Mo bond, and the bending vibrations of the O atom attached to three Mo atoms, respectively ...
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... the case of PTh/MoO3, all the characteristic peaks of PTh were observed at lower wavenumbers except for one peak at 451.3 cm -1 , which shifted to a slightly higher wavenumber (Fig. ...
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... the reproducibility of both sensors at 1 M concentration of ammonia, methanol, and acetone, the selected sensor pellet was exposed alternately to analyte vapour for 20 s and to air for 20 s to complete one cycle while the change in conductivity was recorded. This experiment was performed for five consecutive cycles comprising a total 200 s (Fig. 10). In this study, the reproducibility of the sensor was determined in terms of % recovery of its initial conductivity (i.e., conductivity at time zero) after completion of the fifth cycle. For the PTh sensor, there was a steady decrease in electrical conductivity after the completion of each cycle. In other words, the conductivity did ...
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... in terms of % recovery of its initial conductivity (i.e., conductivity at time zero) after completion of the fifth cycle. For the PTh sensor, there was a steady decrease in electrical conductivity after the completion of each cycle. In other words, the conductivity did not return to its original value after the completion of the fifth cycle (Fig. ...
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... of analyte molecules. However, the PTh/MoO3-based sensor exhibited much higher reversibility as compared to the PTh sensor. The PTh/MoO3-based sensor showed an excellent dynamic response of electrical conductivity in analyte vapour and in air. After completion of the fifth cycle, its conductivity reverted to very near to its initial value (Fig. 10b). The reversibility of the J o u r n a l P r e -p r o o ...
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... area, the greater the number of active sites and hence the greater the rate of adsorption. Therefore, the improved performance of the PTh/MoO3-J o u r n a l P r e -p r o o f based sensor may be related to the greater surface area provided by the MoO3 NPs, which enable a greater number of active sites for the adsorption of analyte molecules (Fig. ...
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... 24,25 PTh interacts by means of adsorption and desorption mechanism with NH 3 gas. 26,27 Figure 2 exhibits the summary of these CPs (PANI, PPy, and PTh) interaction mechanisms with NH 3 gas molecules. ...
... Mechanisms were optimized with additional information from open-access sources. 26,28,29 conducted to apprehend the current situation, key topics, and future outlook of the CPAD sensor field by using the largest reliable database held by SCOPUS itself. [30][31][32] ...
Conducting polymers (CPs)-based sensing materials have emerged as a prominent option for the sensitive detection of gaseous ammonia (NH 3) due to their cost-effectiveness, ease of production, and increased sensing performance. Although more than 1400 articles published in the past decades, no bibliomet-ric analysis which can highlight the publication trend and research clusters within the scope of conducting polymer-based sensors for ammonia detection (CPAD) is available in the literature. The aim of this bibliometric analysis is to document the research trends of CPAD during the last 27 years, since the inception of the first report on conducting polymer as potential NH 3 gas sensor which has been published in 1994. The bibliometric analysis was carried out using VOSviewer and Publish or Perish software to analyze keywords trend, the impact of the scientific community, publishing trends among the authors, institutions, and countries. The review discovered that over 80% of the relevant papers produced after 1994, based on bibliographical examination of 1476 Scopus-indexed articles. Citation analysis was used to identify key authors and articles that shaped the evolution of this literature. Overall, this bibliometric approach allows us to analyze the evolution of a CPAD field while also offering insights on the field's growing areas.
... Several other room temperature NH 3 gas sensors have been designed using nanocomposites. In [21], the NH 3 gas sensor was obtained on the basis of a polythiophene/molybdenum oxide nanocomposite. In [22], an NH 3 gas sensor was obtained using an organic PEDOT:PSS layer. ...
A gas sensor based on ZnO has been designed, which demonstrates sensitivity to NH3 under standard conditions (temperature, 25 °С; pressure, 101.3 kPa). The experimental sample was manufactured by magnetron sputtering at direct current. A VUP-5M vacuum unit with an original material-saving magnetron was used to produce ZnO films. To analyze the efficiency of the gas sensor to ammonia (NH3) under standard conditions, its operating characteristics were studied. The concentration of NH3 for investigating operating characteristics was chosen at the level of 25 ppm. To determine the resistivity of the contacts of the instrument structure, the current-voltage characteristics of the gas sensor were examined in the voltage range between −100 and +100 V. Based on the results of investigating the current-voltage characteristics, which have a linear character, the resistivity of the contacts was confirmed. To study the sensitivity of the gas sensor to the target gas, the change in resistance of the sensitive layer of the gas sensor under the influence of NH3 with a concentration of 25 ppm under standard conditions was explored. The study results demonstrated the high sensitivity of the gas sensor to the target gas – at the level of 229 relative units. The investigation of the response and recovery time of the gas sensor showed that the ZnO-based gas sensor has a response and recovery time of 20 and 26 s, respectively. The selectivity of the ZnO-based gas sensor was studied. The selectivity study was carried out by determining the sensitivity of the gas sensor in the presence of vapors of various gases, namely methanol, ethanol, acetone. The study results showed that the reaction to ammonia is selective compared to the reaction to other gases. The results of examining the working characteristics of the ammonia gas sensor demonstrate the high efficiency of its application under standard conditions and a low concentration of the target gas
... Therefore, by combining the excellent properties of both the CPs (organic) and semiconductor metal oxide/carbon nanomaterials (inorganic) counterpart a new and outstanding class of materials were developed and named as CPs/inorganic nanocomposites [21][22][23][24]. CPs nanocomposites are mostly based on polypyrrole (PPy), polyaniline (PANI), poly (3,4-ethylenedioxythiophene) (PEDOT), polythiophene (PTh) and their derivatives and nanocomposites which were utilized for the production of very efficient gas/vapour sensors [25][26][27][28][29][30][31][32][33][34][35][36]. ...
Development of highly efficient gas/vapour sensor is an urgent necessity because of rapidly increasing emission of various hazardous and highly flammable gases/vapours. The chemical detection and quantification are extremely important to control and monitor the pollutant or toxins and flammable gases/vapours to ensure the safety of ecosystem. Nano sensors have fascinated massive interest owing to their excellent performance along with being compact, easy to fabricate and cost effective. Over the years, polypyrrole (PPy) is one of the conducting polymers (CPs), proved to be excellent materials for gas/vapour sensing application at room temperature operations. But pristine PPy has some drawbacks such as poor selectivity & reversibility and poor long-term stability. However, these sensing properties can be significantly improved by making nanocomposites of PPy by adding semiconductor metal oxide and/or carbon nanomaterials which amplify adsorption, catalytic reaction and charge transport behaviour. Hence, PPy nanocomposites have been employed as the gas/vapour sensing materials for detection and monitoring of various gases such as ammonia (NH3), liquefied petroleum gas (LPG), hydrogen disulphide (H2S), carbon oxides (CO & CO2), nitrogen oxides (NO & NO2), hydrogen (H2) and different volatile organic compounds (VOCs) such as acetone, ethanol, methanol, formaldehyde, toluene etc. Current review is focused on the gas/vapour sensing properties of PPy nanocomposites along with future prospects for the development of new PPy nanocomposites for the fabrication of highly efficient sensors.
... The PTh-nanocomposite yielded a 971 F/g, 66.1 Wh/kg, and 7000 W/kg specific capacitance, energy, and power densities, respectively, while capacitance stability of ~ 98% can be achieved within 10,000 cycling. The electrical conductivity of PTh-based nanocomposites and their sensing capability was also reported by Ahmad [45]. Ahmad's experimental results showed that molybdenum inclusion in PTh could enhance its electrical conductivity by 1 order of magnitude and yield a better sensitivity performance. ...
The synergy between graphene and conducting polymers has the potential to revolutionize the energy storage sector to a more dependable, sustainable, and affordable energy source. Introducing graphene nanoparticles in the conductive polymers (polypyrrole and polythiophene) nanoparticles is a prospective technique to increase the charge transfer efficiency of the resulting nanocomposite. Subsequently, the fabrication method of graphene-polymer nanoelectrode is the most critical factor responsible for their excellent performance. This review presents a concise summary of graphene (Gr), polypyrrole (PPy), and polythiophene (PTh) synthesis techniques. The study revealed that the dispersion of nanoparticles could be controlled by suitable solvent, mixing approach, and drying conditions. In addition, the PPy/PTh/Gr nanocomposite is envisaged to be a promising nanoelectrode for sustainable and efficient energy storage capabilities. The future approaches to developing improved materials synthesis techniques for multi-applications (supercapacitors, sensors, and photovoltaic) are also provided.
... PTh and its derivatives stood out among gas sensors owing to their distinctive doping and de-doping mechanisms that produce a change in electrical conductivity when exposed to various chemicals and gases. [22][23][24][25][26][27][28][29][30][31][32][33] 2-Dimensional nanomaterials have captured a signicant deal of attention due to its several uses in the past ten years and their extremely high surface area to volume ratio. Researchers have been fascinated by MXene, graphene, g-C 3 N 4 , and MoS 2 among these materials because of their remarkable capacity as sensing materials, supercapacitors, and hydrogen evolution reactions. ...
... The characterization of PTh and PTh/g-C 3 N 4 nanocomposites was performed by FT-IR (PerkinElmer 1725 instrument on KBr pellets), XRD (Bruker D8 diffractometer with Cu Ka radiation at 1.5418 Å), TGA {PerkinElmer (Pyris Diamond) instrument}, SEM {JEOL, JSM, 6510-LV (Japan)}, and TEM {JEM 2100, JEOL (Japan)} techniques respectively. [21][22][23][24][25][30][31][32][33] DC electrical conductivities and sensing experiments were performed by four-in-line probe instrument attached with the PID controlled oven manufactured by Scientic Equipment, Roorkee, India. The thermal stability as a function of DC electrical conductivity under isothermal and cyclic ageing environments was evaluated for all the nanocomposites. ...
... The loss in electrical conductivity may be due to the ethanol present in petrol because as we know petrol comprises of mainly non- polar hydrocarbons with some mixing of ethanol to increase its octane rating. 33 The hydrocarbon molecules in petrol being non-polar at ambient temperatures, don't interact electronically with polarons of PTh. The ethanol (C 2 H 5 OH) in petrol interacts with the polarons of PTh, disrupting the conductivity channels by impeding the movement of some polarons of PTh, causing decline in DC electrical conductivity. ...
The automobile vehicles must be operated on fuel containing no more than 10% ethanol. Use of fuel having more than 10% ethanol may cause engine malfunction, starting and running issues, and material degradation. These negative impacts could cause irreversible damage to the vehicles. Therefore, ethanol mixing in petrol should be controlled below 10% level. The current work is the first to report sensing of ethanol mixing in petrol with reference to the variation in the DC electrical conductivity of polythiophene/graphitic-carbon nitride (PTh/gC3N4) nanocomposite. The in situ chemical oxidative method of polymerization was used for synthesizing PTh and PTh/gC3N4 nanocomposite. Fourier transform infrared spectroscopy (FT-IR), X-rays diffraction (XRD), thermo-gravimetric analysis (TGA), transmittance electron microscopy (TEM) as well as scanning electron microscopy (SEM) analysis were used for confirmation of the structure along with morphology of the PTh and PTh/gC3N4 nanocomposite. The thermal stability of DC electrical conductivity of PTh and PTh/gC3N4 nanocomposite were tested under isothermal and cyclic ageing condition. The sensing response of PTh and PTh/gC3N4 nanocomposite as a function of DC electrical conductivity were recorded in petrol and ethanol atmosphere. The sensing response of PTh/g-C3N4 nanocomposite in petrol atmosphere was 6.1 times higher than that of PTh with lower detection limit to 0.005 v/v% of ethanol prepared in n-hexane.
... Since the development of first conducting polymer [1], researchers have developed immense enthusiasm due to its exceptional properties like easy preparation, high yield, thermal stability, electrical conductivity [2][3][4][5][6][7][8] and mechanical properties etc [9] and there uses in a variety of disciplines such as batteries [10], sensors [11][12][13][14][15], electrochromic displays [16,17] and so on. Among the different types of conducting polymers, polythiophene (PTh) draw so much of attention in field of photo-catalysis [18], sensors [19][20][21][22][23][24][25][26][27], solar cells [28], and supercapacitors [29]. ...
... where: V, S, W and I denotes voltage (V), probe separation (cm), the pellet-width (cm), current (A) and r denotes the DC electrical conductivity (Scm À1 ) respectively [12][13][14][15]25]. ...
Here in this work, we are reporting thermally stable DC electrical conductivity of silicon carbide nanocomposite with polythiophene and its sensing behavior towards ethanol. Polythiophene (PTh) and Polythiophene/SiC (PTh/SiC) nanocomposite were synthesized by in-situ process of polymerization via oxidation route using CTAB (cetyltrimethylammonium bromide) as a surfactant and characterized by X-rays diffraction (XRD), Fourier transforms infrared spectroscopy (FT-IR), Scanning electron microscopy (SEM) and Transmittance electron microscopy (TEM) analysis. Stability of DC electrical conductivity of PTh and PTh/SiC nanocomposite were examined at different temperature ranges from 50°C to 130°C in isothermal and cyclic conditions. PTh/SiC nanocomposite showed high steadiness of DC electrical conductivity than that of PTh in different thermal ageing conditions. Sensing behavior of PTh/SiC nanocom-posite towards 1 M ethanol was recognized as steady with time and reversible in cyclic process.
... This response results suggests that a concentration of ammonia and methanol even lower than 0.1 M can be efficiently sensed by pTSA/Ag-Pani@MoS 2 . The percentage sensing response (SR) was calculated by [33]: SR (%) = (Change in electrical conductivity/Initial conductivity) × 100 (5) ...
... This response results suggests that a concentration of ammonia and methanol even lower than 0.1 M can be efficiently sensed by pTSA/Ag-Pani@MoS2. The percentage sensing response (SR) was calculated by [33]: SR (%) = (Change in electrical conductivity/Initial conductivity) × 100 (5) The percentage sensing response of pTSA/Ag-Pani@MoS2 and pTSA/Pani@MoS2 for 1 M ammonia was 70.48 and 53.70% and for methanol, 51.17 and 38.62%, respectively. This suggests that both pTSA/Ag-Pani@MoS2 and pTSA/Pani@MoS2 are more responsive towards ammonia, with pTSA/Ag-Pani@MoS2 showing much higher sensitivity towards both ammonia and methanol. ...
We report the synthesis of silver anchored and para toluene sulfonic acid (pTSA) doped polyaniline/molybdenum disulfide nanocomposite (pTSA/Ag-Pani@MoS2) for highly reproducible room temperature detection of ammonia and methanol. Pani@MoS2 was synthesized by in situ polymerization of aniline in the presence of MoS2 nanosheets. The chemical reduction of AgNO3 in the presence of Pani@MoS2 led to the anchoring of Ag to Pani@MoS2 and finally doping with pTSA produced highly conductive pTSA/Ag-Pani@MoS2. Morphological analysis showed Pani-coated MoS2 along with the observation of Ag spheres and tubes well anchored to the surface. Structural characterization by X-ray diffraction and X-ray photon spectroscopy showed peaks corresponding to Pani, MoS2, and Ag. The DC electrical conductivity of annealed Pani was 11.2 and it increased to 14.4 in Pani@MoS2 and finally to 16.1 S/cm with the loading of Ag. The high conductivity of ternary pTSA/Ag-Pani@MoS2 is due to Pani and MoS2 π–π* interactions, conductive Ag, as well as the anionic dopant. The pTSA/Ag-Pani@MoS2 also showed better cyclic and isothermal electrical conductivity retention than Pani and Pani@MoS2, owing to the higher conductivity and stability of its constituents. The ammonia and methanol sensing response of pTSA/Ag-Pani@MoS2 showed better sensitivity and reproducibility than Pani@MoS2 owing to the higher conductivity and surface area of the former. Finally, a sensing mechanism involving chemisorption/desorption and electrical compensation is proposed.
... Organic conducting polymers, including polypyrrole (PPy) [24], polyaniline (PANI) [25,26], polythiophene (PTh) [27], and poly (3, 4-ethylene dioxythiophene) (PEDOT) [28,29] are the ideal candidate materials for fabricating NH 3 sensors due to their low cost, environmental stability, and low working temperature. However, the single-conductive polymer material also has some drawbacks, including low sensitivity and unsatisfactory damp-heat stability [30]. ...
Developing low-cost and high-performance ammonia sensors is significant to the current air pollution control and non-invasive diagnosis of human diseases. In this work, in situ polymerization of poly(aniline-co-pyrrole) (PAPY) is on flexible porous polyvinylidene fluoride (PVDF)-based sensitive membrane (PAPYP). Based on the adjustment of the poly(aniline-pyrrole) copolymer backbone structure and the dual role of the porous substrate, the sensor exhibited excellent ammonia gas sensing performance. The response of the PAPYP sensor to 1 ppm NH3 at room temperature was improved to 93%. It has a low detection concentration of 0.05 ppm for NH3. In addition, the PAPYP sensor has excellent long-term stability and outstanding flexibility. Finally, based on the low-temperature working environment of the sensor, we analyzed and discussed the influence of relative humidity and temperature on the gas-sensing characteristics of the PAPYP sensor to realize error correction in practical applications. This study provides commercial application potential for ammonia concentration detection related to human health.
... An interesting report about developing paper-electronic-based room temperature NH 3 gas sensor by Maity et al. [5], employed perovskite halide as the active materials where the current started to increase at 10 ppm of NH 3 with a response/recovery time of ~135s/112s and an estimated resolution of ~10 ppb. Several other room temperature NH 3 gas sensors were developed by using polypyrrole-graphene nanocomposite decorated with titania nanoparticles [7], reduced graphene oxide-zinc oxide nanocomposites [8], porous metal-graphene oxide nanocomposite [9], rGO/Co 3 O 4 nanocomposites [10], zinc oxide encapsulated polypyrrole (ZnO-en-PPy) composite [11], polythiophene/molybdenum oxide nanocomposite [12], graphene-PEDOT:PSS [13], polyaniline [14], ZnO nanoparticle/rGO by-layer thin films [15] and ZnO nanowire/nanorod array [3,16]. ...
We demonstrate room temperature (25 °C) and low temperature (≦100 °C) NH3 gas sensing properties of Cd-doped ZnO nanorods (NRs) synthesized by a low temperature (90 °C) hydrothermal method. Although, the Cd concentration in the growth solution was varied over a large range from 0 to 80 mol %, the maximum estimated Cd doping concentration in ZnO NRs was 0.5 at % (80 mol %). Structural analysis confirmed the successful doping of Cd in ZnO and microstructure investigation revealed the presence of single nanorod and flower like nanorods in the same ensemble whose dimensions reduced with the Cd doping concentration. Photoluminescence and Raman spectra analyses confirmed the increase of defect concentrations in ZnO NRs by Cd doping thereby enhancing the overall gas sensing. In response to NH3, the nanostructure sensors exhibited a gradual increase in the sensitivity with the Cd doping concentration where the 0.5 at % Cd-doped ZnO NRs showed the highest sensitivity with an enhancement of ∼9% (at 60 ppm NH3) as compared to the un-doped ZnO. The sensitivity continued to rise with the increase of temperature from 110% (25 °C), 120% (50 °C), 170% (75 °C) to 243% (100 °C) indicating a gigantic enhancement of ∼133% at 100 °C from 25 °C. The Cd-doped ZnO NRs also revealed superior specificity of detecting NH3 over NO2, and H2S even at room temperature.
... But the presence of other analyte gases affects the inter-chain conduction [70]. Methanol, ammonia, and acetone vapor sensor were studied based on the electrical conductivity of the synthesized polythiophene /molybdenum oxide (PTh/MoO 3 ) nanocomposite [71]. The sensing response (in percent) of PTh and PTh/MoO 3 were compared for 1 M of ammonia, methanol, and acetone. ...
Environmental pollution is the main issue in most countries due to industrialization and fossil fuel burning. Pollution affects the quality of air and the fertility of the soil, which causes infections in the respiratory system and affects our immune system through food. Wherefore the environment has to be monitored to regulate its quality as these hazardous gases affect human health and marine life. Another vital requirement in today’s medical science is the diagnosis of disease at the earliest through a noninvasive process. These tasks are accomplished by gas sensors that detect noxious gases in the surroundings and are also used in the medical field to diagnose diseases by breathing analysis. Metal oxide semiconductors are extensively used in gas sensors due to their high sensitivity and compatibility but selectivity and high operating temperature are their main drawbacks. This review overviews the major metal oxide semiconductors, the sensing mechanism of chemiresistive metal oxide semiconductor-based gas sensors, and various approaches that have been carried out to overcome their limitations. In this paper, we have reviewed the detection of acetone and ammonia which act as a biomarker for some diseases, and the detection of harmful gases such as alcohol and carbon monoxide using gas sensors developed on metal oxide semiconducting materials for a safe living environment.
