Biswajit Mandal

Bio: Biswajit Mandal is an academic researcher from Indian Institute of Technology Indore. The author has contributed to research in topics: Transmission electron microscopy & Photodetector. The author has an hindex of 7, co-authored 17 publications receiving 123 citations.

Highly Selective and Sensitive Methanol Sensor Using Rose-Like ZnO Microcube and MoO 3 Micrograss-Based Composite

Abstract: Rose-like ZnO microcube/MoO3 micrograss-based composite was synthesized via hydrothermal process followed by solution-based synthesis approach. The crystal structure, chemical state, morphology, and elemental analysis of the obtained rose-like composite were examined by X-ray diffraction, X-ray photoelectron spectroscopy, field emission scanning electron microscopy, and energy dispersive X-ray spectrometer, respectively. The results indicated that rose-like ZnO microcube/MoO3 micrograss composite was obtained where ZnO microcube pistil and MoO3 micrograss petal were formed. Furthermore, volatile organic compounds sensing performance of the rose-like composite was examined, where sensors presented outstanding sensing performance toward methanol including high selectivity and sensitivity, low-optimal operating temperature as well as very stable response-recovery characteristics, and long-term stability. Such sensing performance can be ascribed to a combined effect of the unique rose-like structures and band formation between ZnO/MoO3 n–n heterojunction.

π-Conjugated Amine-ZnO Nanohybrids for the Selective Detection of CO2 Gas at Room Temperature

Abstract: The development of a new type of hybrid material comprising naphthalene-based π-conjugated amine (NBA) and zinc oxide (ZnO) nanohybrid, grown in situ on polydimethylsiloxane (PDMS) flexible substra...

Impact of Schottky junctions in the transformation of switching modes in amorphous Y2O3-based memristive system

Abstract: In this report, we study factors that dominate the mode transformation of resistive switching (RS) in yttria based memristive devices. It is found that amorphous yttria films are more suitable for RS whereas highly crystalline films are counterproductive for RS. The transformation from unipolar to bipolar resistive switching mode is demonstrated in our devices via moving from a system of single Schottky barrier diode (SBD) to double SBD. The conduction mechanism behind these transformation mechanisms is found to be predominantly interfacial. We also report a forming-free Al/Y2O3/Al based memristor fabricated by the dual ion beam sputtering without any post-processing steps for the first time. It shows stable switching behavior for >29 000 cycles with good retention (105 s) characteristics.

Effect of Surface Variations on the Performance of Yttria Based Memristive System

Abstract: The effect of the statistical distribution of the grain surface area on the variations of switching voltages (set/reset or both) has been discussed in this report. Dual ion beam sputtered yttria-based memristive devices show unipolar and bipolar resistive switching (RS) for amorphous thin-film and polycrystalline thin-film devices, respectively. Field emission scanning electron microscope image analysis techniques reveal that the standard deviation (SD) of the switching voltages is directly correlated with the SD of grain surface area of oxide layers. It is found that devices with the amorphous thin film have a smaller SD of the switching voltages than polycrystalline thin-film devices. The endurance measurement of the device with amorphous oxide layer indicates highly reliable and reproducible RS characteristics for ~23 000 switching cycles.

Review on Smart Gas Sensing Technology.

Abstract: With the development of the Internet-of-Things (IoT) technology, the applications of gas sensors in the fields of smart homes, wearable devices, and smart mobile terminals have developed by leaps and bounds. In such complex sensing scenarios, the gas sensor shows the defects of cross sensitivity and low selectivity. Therefore, smart gas sensing methods have been proposed to address these issues by adding sensor arrays, signal processing, and machine learning techniques to traditional gas sensing technologies. This review introduces the reader to the overall framework of smart gas sensing technology, including three key points; gas sensor arrays made of different materials, signal processing for drift compensation and feature extraction, and gas pattern recognition including Support Vector Machine (SVM), Artificial Neural Network (ANN), and other techniques. The implementation, evaluation, and comparison of the proposed solutions in each step have been summarized covering most of the relevant recently published studies. This review also highlights the challenges facing smart gas sensing technology represented by repeatability and reusability, circuit integration and miniaturization, and real-time sensing. Besides, the proposed solutions, which show the future directions of smart gas sensing, are explored. Finally, the recommendations for smart gas sensing based on brain-like sensing are provided in this paper.

MoSe2 nanoflakes based chemiresistive sensors for ppb-level hydrogen sulfide gas detection

Abstract: Detection and quantification of hydrogen sulfide (H2S) gas is important as it influences directly human health, our environment, and operations of several industries including food and beverages, oil, construction, and medicine. It also acts as biomarker in diagnosis of halitosis at early stage. We report herein liquid exfoliated MoSe2 nanoflakes based stable chemiresistive H2S gas sensor which operate at moderate temperature of 200℃. The response of p-type MoSe2 gas sensor device (when operated in ambient environment) was found to be varying between 15.87%–53.04% when the concentration of H2S was varied between 50 ppb – 5.45 ppm. The response of the device decreases when the measurements were done in synthetic air environment and it varies between 7.13%–19.87% for the concentration range of 500 ppb - 5.45 ppm. The response (%), recovery rate (%), hysteresis, experimental lowest detection limit etc. of the device suggest that the device performs better when operated in ambient than in synthetic air which suggest its real time device application. The response time and recovery time of the sensor are 15 s and 43 s respectively for 100 ppb of H2S. The sensor performance was found to be highly repeatable with sensitivity of 5.57%/ppm of H2S. The theoretical limit of detection and limit of quantization of the device were found to be 6.73 ppb and 22.44 ppb respectively. Based on chemical analysis, a plausible mechanism based on charge transfer phenomenon has been proposed for this sensor.

Porous organic polymers as a platform for sensing applications.

Abstract: Sensing analysis is significantly important for human health and environmental safety, and has gained increasing concern. As a promising material, porous organic polymers (POPs) have drawn widespread attention due to the availability of plentiful building blocks and their tunable structures, porosity and functions. Moreover, the permanent porous nature could provide a micro-environment to interact with guest molecules, rendering POPs attractive for application in the sensing field. In this review, we give a comprehensive overview of POPs as a platform for sensing applications. POP-based sensors are mainly divided into five categories, including fluorescence turn-on sensors, fluorescence turn-off sensors, ratiometric fluorescent sensors, colorimetric sensors and chemiresistive sensors, and their various sensing applications in detecting explosives, metal ions, anions, small molecules, biological molecules, pH changes, enantiomers, latent fingerprints and thermosensation are summarized. The different structure-based POPs and their corresponding synthetic strategies as well as the related sensing mechanisms mainly including energy transfer, donor-acceptor electron transfer, absorption competition quenching and inner filter effect are also involved in the discussion. Finally, the future outlook and perspective are addressed briefly.