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•Synthesis of material is done by sol-gel method which is easy and cost effective.•SEM shows that the film is macro porous and porosity lies in range of 50–100nm.•Minimum particle ...size calculated by TEM is 6.7nm.•The LPG sensing of barium titante film below LEL was performed for the first time at room temperature.•The value of maximum sensitivity was found 3.5 and % sensor response was found 250 for 4 vol. % LPG.
Perovskite barium titanate (BaTiO3) nanocomposite thin film has been prepared using spin coating technique. Surface morphological, structural, compositional and optical properties of the film were investigated by various techniques such as SEM, XRD, TEM, EDS, UV-Spectroscopy, Raman spectroscopy and FTIR. SEM images showed the macroporous cubic structure of the film. The minimum crystallite size was evaluated as 11nm by XRD and confirmed by TEM. Band gap of BaTiO3 was evaluated as 3.9eV. Raman Spectroscopy confirmed the formation of BaTiO3 at 540cm−1. LPG sensings were carried out for vol.% 0.5–4 of LPG and sensor was found robust for the detection of LEL for LPG also.
This study aims to determine whether the analysis of volatile organic compounds (VOCs) in exhaled breath can be used as a non-invasive monitoring tool for diabetes patients. Here, we are reporting ...perovskite BaSnO3 based quick responsive and highly sensitive acetone biosensor for the sensing of low concentration acetone in the human breath. The BaSnO3 nanomaterial has been prepared by the sol-gel assisted hydrothermal method and confirmed by various characterization tools such as X-ray diffraction (XRD), Field-emission scanning electron microscopy (FE-SEM), UV–Visible absorption spectroscopy and Dynamic light scattering (DLS) analysis. XRD result reveals the cubic polycrystalline nature with space group of Fm-3 m of BaSnO3 with the average crystallite size of 24.197 nm and induced strain of 1.441 × 10-4. From the X-ray Photoelectron Spectroscopy (XPS) binding energy separation between Barium and Tin doublets are found to be 15.351 eV and 8.426 eV, which confirms the presence of Ba2+ and Sn4+ states respectively. For the exhale human breath level acetone of 1 ppm, the fabricated device shows the sensor response of 6.795 along with the fast performance with 3.325 s response time. The highest sensing response was found 45.850 for 50 ppm of acetone at 80 °C operating temperature and such sensing device shows the excellent linearity between blood glucose level and sensor response.
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•This research reports the monitoring of blood glucose levels by exhaling breath analysis.•The chemiresistive sensor based on BaSnO3 nanorods shows the response of 45.85 to acetone.•An excellent linearity for the blood glucose level and acetone level in exhaled human breath.•This sensor device exhibits fast performance within 3.32 s response time.
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•Detection and measurements of a very hazardous gas (NO2) and flammable gas (LPG) were carried out.•Thin film of TiO2-ZnO-PANI composite was fabricated over inter digital electrodes ...(IDEs) by spin coating technique.•ZnO-TiO2-PANI based sensor is highest among the reported values by the previous researchers.•ZnO-TiO2-PANI based sensor was found to have maximum sensing response as 87 for 2000 ppm of LPG and 412 for 20 ppm of NO2 at RT.
The present paper reports the in-situ chemical polymerization of nanocomposites thin film composed by titanium dioxide (TiO2), zinc oxide (ZnO) and polyaniline (PANI). It was found that nanocomposites sensor is highly selective and shows response to low concentration. To improve the sensing response characteristics of ZT thin film, PANI is incorporated. Thin film based LPG sensor of ZnO-TiO2-PANI composite was fabricated by spin coating of ZnO-TiO2 nanoparticles doped with PANI over inter digital electrodes (IDEs). The thin film was characterized by using XRD, SEM, TEM, UV–vis, BET and FTIR. It was also tested for gas sensing properties of LPG/NO2 which are well known flammable and toxic gases. The measured response for ZnO-TiO2-PANI based sensor was 87 for 2000 ppm of LPG and 412 for 20 ppm of NO2 at room temperature towards other testing gases together with Acetone, IPA, NH3 and CO2.
•Detailed study of various nanomaterials as opto-electronic humidity sensor.•Focused on the techniques used in such type of optical sensors.•The sensing materials were deposited either on the base of ...the prism or on the U-shaped fibre.•The mode of propagation of light may be transmission, reflection or partially refraction.•Being optical, such types of sensors are very useful for the detection of moisture level at remote places.
The present paper reports the detailed study of various metal oxide nanomaterials as opto-electronic humidity sensor. The sensor elements were fabricated and characterized as thin or thick film based on the semi-conducting metal oxide. As semi-conducting metal oxides are known for their n-type conduction because of the presence of oxygen vacancies and change in refractive indices with the exposure of moisture therefore they were proven to be very good sensors for humidity. Depending upon the need, the sensing materials were deposited either on the base of the prism or on the U-shaped borosilicate glass rods or on some other transparent substrates for opto-electronic sensing. Light from LED or He–Ne laser was launched into the sensing element from one side and collected into the other side by optical power meter. The mode of propagation of light was transmission, reflection or partially refraction. Modulations in the intensity of light with changes in humidity were recorded. Being optical in nature, such types of sensors are very useful for detection of moisture level at remote places or unmanned stations. The primary purpose of this paper is to focus on the techniques used in these sensors.
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•Description of the precursor used for the synthesis of multiwalled carbon nanotube, along with extraordinary structural and bonding characterization of these nanomaterials.•A ...detailed theoretical approach for humidity sensing with CNTs.•Room temperature humidity sensing with higher accuracy and fast response and recovery time. In this work, we have improved the response time from 60 s to 24 s after functionalization.•Finally, the manuscript reports the broader impacts and advantages of the DLICVD over other CVD systems for MWCNT growth and their possible application in humidity sensing.
One-dimensional carbon nanostructures e.g. Carbon nanotubes (CNTs) possess outstanding physical properties owing to their unique structure and atomic arrangement. High electrical conductivity, highly exposed surface area and stability of these carbon nanostructures introduce them as the leading choice of nanomaterials for a number of electrical and industrial applications like humidity and gas sensing. The conductance or capacitance of CNTs varies greatly with the adsorption-desorption of molecules such as hydroxyl (OH−) ions. In this paper, we report the preparation of carbon nanotubes based thin film using a CVD technique which has been characterized by using Scanning Electron Microscopy (SEM), UV–vis microscopy and X-ray diffraction technique. The characterized film was investigated as a humidity sensor. In the experimental part, the variations in the impedance of film were observed by Impedance Analyzer 6440 B on varying the humidity levels. In the theoretical part, we have simulated the CNTs using Ab initio density functional theory (DFT) calculations to investigate the formation of endohedral complexes among CNTs and OH− groups. The binding energy, dipole moment, electronegativity and HOMO-LUMO gaps were monitored by increasing the hydroxyl group levels, which results in its better use in developing a robust and cost-effective humidity sensor.
Acetone plays a vital role as a cleanser for current cosmetic –products particularly nail paint, gels, fairness creams, face-wash, etc. Inhaling of acetone during cleaning skin and face can cause ...severe health issues which demand a highly sensitive acetone sensor. Formation of cadmium oxide (CdO) nanoparticles, two-dimensional molybdenum oxide (2D MoO3) nanosheets, and MoO3-CdO nanoparticles were investigated in terms of physical characteristics using the X-ray diffraction (XRD), Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy (XPS), Dynamic light scattering (DLS) and UV–visible absorption analysis. Characterization studies witnessed the formation of MoO3-CdO nanoparticles with a characteristic energy band gap, crystallite size, and particle size distribution as 3.80 eV, 38.69 nm, and 2–50 nm, respectively. As fabricated MoO3-CdO nanoparticles-based sensor exhibited an excellent response of 13.48 at 25 ppm with rapid response and recovery times of 6.95 s and 8.34 s respectively. Acetone sensing studies were also conducted for the products of a few commercial companies like Acetone pure, Beauty Company, and Lakme in nail polish removers. The study of MoO3-CdO nanoparticles may be used for acetone sensing in cosmetic applications.
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•MoO3- CdO nanoparticles based sensing device for acetone detection.•Sensing studies were conducted for nail polish removers obtained from commercial companies.•Detection of acetone (1 ppm) with the sensor response 1.92 (res. and reco. time as 2.01 s and 2.85 s).•As fabricated sensor device exhibited an excellent response of 13.48 for acetone (25 ppm).•Rapid response and recovery time of 6.95 s and 8.34 s for this sensing device.
In this study, an enhanced photoresponse was observed in the Mn-Co Nanoferrites (MCFs)-Polyaniline (PANI) nanohybrid architecture due to the formation of interface between PANI and MCFs, which ...provided a conduction pathway for the movement of charge carriers, and these interfaces were observed in a high-resolution transmission electron micrograph (HR-TEM). X-ray photoelectron spectroscopy (XPS) suggests that the carbon (C 1s) of the MCF-PANI nanohybrid shows peaks at 287.80 eV for C&z.dbd;O, 286.17 eV for C-O, 285.24 eV for C-N, 284.50 eV for the sp
3
hybridized carbon (C-C/C-H) and 283.84 eV for the sp
2
hybridized carbon (C&z.dbd;C). Current-voltage (
I
-
V
) curves reveal an ohmic nature of the MCF-PANI nanohybrid photodetector device. The photoresponse measurements were analyzed using the trap depth concept, demonstrating that the conductive polymer increases the photoconduction mechanism efficiency of MCFs. The constructed photodetector device exhibits a high photoresponsivity of 22.69 A W
−1
, a remarkable detectivity of 1.36 × 10
12
cm Hz
1/2
W
−1
and a fast rise/decay time of 0.7/0.8 s. The excellent performance of the as-fabricated photodetector device could be explained by the intimate interaction between MCFs and PANI at their interface.
In this study, an enhanced photoresponse was observed in the Mn-Co Nanoferrites (MCFs)-Polyaniline (PANI) nanohybrid architecture. The excellent performance of the photodetector device could be explained by the intimate interaction between MCFs and PANI at their interface.
A nano-enabled low-trace monitoring system for acetone has the potential to revolutionize breath omics-based non-invasive diagnosis of human diabetes and environmental monitoring technologies. This ...unprecedented study presents the state-of-the-art facile and economic template-assisted hydrothermal route to fabricate novel CuMoO4 nanorods for room temperature breath and airborne acetone detection. Physicochemical attribute analysis reveals the formation of crystalline CuMoO4 nanorods with diameters ranging from 90 to 150 nm, and an optical band gap of approximately 3.87 eV. CuMoO4 nanorods-based chemiresistor demonstrates excellent acetone monitoring performance, with a sensitivity of approximately 33.85 at a concentration of 125 ppm. Acetone detection is rapid, with a response time of 23 s and fast recovery within 31 s. Furthermore, the chemiresistor exhibits long-term stability and selectivity towards acetone, compared to other interfering volatile organic compounds (VOCs) commonly found in human breath such as ethanol, propanol, formaldehyde, humidity, and ammonia. The linear detection range of acetone from 25 to 125 ppm achieved by the fabricated sensor is well-suited for human breath-based diagnosis of diabetes. This work represents a significant advancement in the field, as it offers a promising alternative to time-consuming and costly invasive biomedical diagnostics, with the potential for application in cleanroom facilities for indoor contamination monitoring. The utilization of CuMoO4 nanorods as sensing nanoplatform opens new possibilities for the development of nano-enabled, low-trace acetone monitoring technologies for non-invasive diabetes diagnosis and environmental sensing applications.
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•Engineering CuMoO4 nanorods using economic CTAB-assisted hydrothermal route.•Breath/airborne acetone at low temperature 80 °C in the range of (25–125) ppm.•Sensor exhibits high sensor response of 33.85 at 125 ppm.•Fast response and recovery times 23 s and 31 s at 25 ppm are found.•Potential to develop a non-invasive biosensor for breath-based diabetes diagnosis.
Nickel-zinc iron oxide (NZF) was introduced into a polyaniline (PANI) matrix by an
in situ
chemical oxidation polymerization approach. The surface composition and chemical states were investigated by ...X-ray photoelectron spectroscopy (XPS), which revealed an Fe 2p spectrum with the two peak positions of Fe 2p
3/2
and Fe 2p
1/2
at 711.00 and 724.48 eV, respectively. Deconvolution of the Fe 2p
3/2
peak revealed two components with binding energies of 713.98 and 718.16 eV, corresponding to the presence of Fe cations in the octahedral and tetrahedral sites. Additionally, the Rietveld refinement of NZF showed a cubic system with the
Fd
3
m
space group. High-resolution transmission electron microscopy (HRTEM) analysis showed that the NZF material strongly interacts with polyaniline, while the selected area electron diffraction (SAED) pattern perfectly matched with the XRD data. Lognormal distribution was used to determine the particle size, which was found to be in the range of 1-100 nm. A flexible photodetector device utilizing the NZF-PANI nanohybrid was fabricated on an environmentally friendly, biodegradable cellulose paper substrate and the device exhibited excellent performance,
i.e.
, a responsivity of 0.069 A W
−1
and detectivity of 7.258 × 10
10
Jones at a very low voltage of 0.1 V. The non-stretched device showed a responsivity of 24.980 A W
−1
at 5 V, whereas at 2 cm
−1
bending curvature, the device showed a responsivity of 20.175 A W
−1
, which was much higher than the responsivity of a commercial photodetector (<0.5 A W
−1
).
Nickel-zinc iron oxide (NZF) was introduced into a polyaniline (PANI) matrix by an
in-situ
chemical oxidation polymerization approach. This nanohybrid was used to fabricate a photodetector device on a biodegradable and flexible paper substrate.
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•2D ZnO nanostructure prepared by the simple organic solvent assisted route.•The interaction between 2D ZnO and photon (Photodetection) was investigated.•The device was fabricated by ...drop casting technique.•At 1.0 V drift responsivity was 60.34 mA/W with the 20% of EQE.
Development of the highly responsive and cost-effective device for UV photodetection has been attracted a lot of attention from the global scientific community. A facile, easy processable and cost-effective synthesis method for the preparation of two dimensional ZnO nanomaterial is presented in this research work. A prepared sample was characterized by different characterization tools. XRD patterns reveal the crystalline nature of prepared ZnO nanostructures. The optical tenability of the material is further described by UV–vis and FTIR spectroscopic analysis. Scanning electron microscopy is used for the surface morphological studies and elemental analysis is done by electron diffraction spectroscopy (EDS). Photodetector performance parameters were analyzed under the illumination intensity of 50 μW/cm2. Various photodetector parameters such as responsivity, detectivity LDR, and EQE were found to be 60.34 mA/W, 4.09 × 1011 Jones, 14.71 dB and 20.45% respectively.
