Search

Triclinic NaCe(WO4)2 with oxygen monovacancy and divacancy has been successfully prepared by a facile cetyltrimethyl ammonium bromide (CTAB) assisted hydrothermal technique. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron...

Acetone is known as the breath biomarker of diabetes. In this paper we have reported on a highly sensitive, stable cobalt chromite (CoCr2O4) thick film-based trace acetone sensor with quick response and recovery times promising for the detection of diabetes from exhaled breath. CoCr2O4 nanoparticles were prepared by a cost-effective and easy sol-gel method. The as prepared nanoparticles were well characterized by sophisticated characterization techniques, such as, XRD, FESEM. TEM, HRTEM, XPS, and BET. Further these nanoparticles were exploited to fabricate a Taguchi type chemoresistive sensor using a customized drop coater. The developed sensor was characterized by I–V measurement. The developed sensor exhibited high p-type response towards 1 ppm of acetone vapor (~3.81 folds), and appreciable resolution between 1 ppm, 2 ppm (response = ~4.82 folds), and 5 ppm (response = ~6.64 folds) acetone vapor at 300 °C. Further, the sensor exhibited fast response and recovery times of ~1.65 s and ~62 s, respectively. Also, the response of the sensor to 1 ppm acetone vapor is appreciably higher than that of 0.2 ppm ethanol, 0.25 ppm ammonia vapor, and saturated moisture. Finally, the sensor is stable for at least 6 months and exhibits repeatable measurements.

In this paper we report to have developed a microporous Copper Chromite (CuCr2O4) thick film based capacitive humidity sensor that exhibits excellent response in the range of 1%–98% RH at room temperature. CuCr2O4 spinel nanopowder was synthesized by a facile sol-gel technique. The as prepared CuCr2O4 nanopowder was screen printed to develop a thick film and it was sandwiched between two parallel electrodes of silver and copper to develop a parallel plate capacitive sensor. The CuCr2O4 nanoparticles and the thick film were well characterized by XRD, XPS, FTIR spectroscopy, Raman Spectroscopy, FESEM, TEM, EDX, and contact angle measurement. Various electrical parameters of the sensor, viz. Capacitance (Cp), Dissipation (D), Conductance (Gp), Susceptance (Bp), and admittance (Y) were measured at different frequencies ranging from 100 Hz to 1 MHz. It was observed that the optimum operating frequency is 1 kHz. At this frequency the sensor exhibited very high sensitivity, especially in the low %RH range of 1%–40% (∼640 pF change in capacitance), low dissipation loss (

Exhaled human breath bears the fingerprints of multifarious pathophysiological conditions, and diseases. In this paper we report for the first time a highly sensitive, selective, and stable barium hexaferrite based sensor for the detection of trace ammonia vapor in exhaled human breath, the biomarker for renal diseases. Barium hexaferrite nanoparticles were synthesized by a facile solid-state reaction route. The as prepared nanopowder and the sensor film were well characterized by using XRD, FESEM, TEM, EDX, XPS, BET, and I-V measurements. The fabricated sensor delineates p-type behavior and the capability to detect ammonia down to 0.2 ppm with reasonably high response of ∼1.46 folds. Further, the sensor showed remarkable response of ∼2.34 folds towards 1 ppm ammonia. The sensor is practically insensitive towards similar concentrations of other major interfering breath volatiles, viz. acetone, ethanol, and saturated moisture. Also, the sensor exhibited fast response (∼2.88 s), and recovery (∼39.4 s) times ensuring real time breath analysis. Finally, long-term stability of the sensor for more than three months renders it suitable for commercial applications.