Tukaram D. Dongale

Assessment of structural, morphological, magnetic and gas sensing properties of CoFe2O4 thin films

Polycrystalline CoFe2O4 thin films are deposited onto the quartz substrates by spray pyrolysis technique. Rietveld refinement analysis confirmed the films are polycrystalline in nature with spinel cubic crystal structure. Rietveld refinement analysis was employed to estimate the cation distribution in spinel lattice sites. Surface micrographs shows the granular morphology with average grain size decreases with increase in solution concentration. The presence of two characteristic absorption bands around 579 and 391cm-1 in the FTIR study confirms the formation of single phase CoFe2O4. Vibrating sample magnetometer measurement confirmed the predominant ferrimagnetic nature of thin films which confirms the maximum saturation magnetization with moderate coercivity was useful for making effective gas sensor. The gas response towards different operating temperatures, gas concentrations and solution concentrations was systematically studied. The films show the maximum gas response 70% at 0.1M solution concentration at 150°C operating temperature. The films are well selective towards NO2 as compared with other test gases with good reproducibility.

Structural and Optical Properties of Nanocrystalline TiO2 with Multiwalled Carbon Nanotubes and Its Photovoltaic Studies Using Ru(II) Sensitizers

In this study, the in situ sol–gel method has been deployed to prepare the titanium dioxide/multiwalled carbon nanotubes (TiO2/MWCNTs) nanocomposite (NCs) powders with varying content of MWCNTs (0.01–1.0 wt %), to construct the dye-sensitized solar cells (DSSCs). First, binder-free NCs were deposited on a transparent-conducting F:SnO2 (FTO) glass substrate by a doctor-blade technique and then anchored with Ru(II)-based dyes to either N719 or ruthenium phthalocyanine (RuPc). The structural and optical properties and interconnectivity of the materials within the composite are investigated thoroughly by various spectral techniques (XRD, XPS, Raman, FT-IR, and UV–vis), electron microscopy (HRTEM), and BET analysis. The experimental results suggest that the ratio of MWCNTs and TiO2 in NCs, morphology, and their interconnectivity influenced their structural, optical, and photovoltaic properties significantly. Finally, the photovoltaic performances of the assembled DSSCs with different content of MWCNTs to TiO2 films anchored with two different dyes were tested under one sun irradiation (100 mW/cm2). The measured current–voltage (IV) curve and incident photon-to-current conversion efficiency (IPCE) spectra of TiO2/0.1 wt % MWCNTs (T@0.1 C) for N719 dye show three times more power conversion efficiency (η = 6.21%) which is opposed to an efficiency (η = 2.07%) of T@0.1 C for RuPc dye under the same operating conditions.

Development of Virtual Reality Tool for Creative Learning in Architectural Education

One of the challenging tasks in engineering education is to bridge the gaps between imagination and real time problems of different engineering areas. The virtual reality (VR) can reduce this gap and also provides clear ideas on the basis of real time problems. The architectural education influenced and goes hand in hands for meeting these crucial challenges using advancements in computer technologies. In this research, we developed a VR tool for improving architectural design education. We explain VR tool as a value addition to the architectural education. The system is based on a general purpose computer, ceiling-mounted projector and passive glasses for Three Dimensional (3D) viewing. The presented work shows that virtual reality technology can considerably progress the efficiency learning by allowing young architects to apply theoretical knowledge to real world problems. In addition, it develops creativity, innovation, communication, problem solving approach, team-working and business skills. Development of Virtual Reality Tool for Creative Learning in Architectural Education

Bipolar resistive switching with coexistence of mem-elements in the spray deposited CoFe2O4 thin film

In the present investigation, we have experimentally demonstrated the bipolar resistive switching with the coexistence of three fundamental memelements in the Ag/CoFe2O4/FTO thin film metal-insulator-metal (MIM) device. The device shows the analog resistive switching behavior and charge transport follows the Ohmic and space charge limited conduction (SCLC) mechanisms. The device transforms from asymmetric to symmetric resistive switching when the SCLC conduction mechanism change to the Ohmic conduction mechanism at higher voltage sweep rates. It was observed that the I–V crossing location of MIM device shifted towards the higher voltage range with increasing voltage sweep rates for both bias regions due to the nanobattery effect. The significant tunneling gap between immature conductive filament(s) and percolation channels was responsible for the coexistence of memelements and nanobattery effect in the Ag/CoFe2O4/FTO thin film MIM device.

Regular ArticleAssessment of structural, morphological, magnetic and gas sensing properties of CoFe2O4 thin films

Polycrystalline CoFe2O4 thin films are deposited onto the quartz substrates by spray pyrolysis technique. Rietveld refinement analysis confirmed the films are polycrystalline in nature with spinel cubic crystal structure. Rietveld refinement analysis was employed to estimate the cation distribution in spinel lattice sites. Surface micrographs shows the granular morphology with average grain size decreases with increase in solution concentration. The presence of two characteristic absorption bands around 579 and 391cm-1 in the FTIR study confirms the formation of single phase CoFe2O4. Vibrating sample magnetometer measurement confirmed the predominant ferrimagnetic nature of thin films which confirms the maximum saturation magnetization with moderate coercivity was useful for making effective gas sensor. The gas response towards different operating temperatures, gas concentrations and solution concentrations was systematically studied. The films show the maximum gas response 70% at 0.1M solution concentration at 150°C operating temperature. The films are well selective towards NO2 as compared with other test gases with good reproducibility.

Impact of collected sunlight on ZnFe 2 O 4 nanoparticles for photocatalytic application

In the present investigation, a series of zinc ferrite (ZnFe2O4) nanoparticles were synthesized using a facile, reproducible and scalable chemical co-precipitation route for sunlight assisted photocatalytic degradation application. In the present work, we have prepared ZnFe2O4 with 1:1, 1:2 and 1:3 M ratio of zinc chloride and ferric chloride respectively. This work reports the photodegradation of organic methylene blue dye molecules using ZnFe2O4 under both normal sunlight, and collected sunlight. Among other annealing temperatures, particularly the ZnFe2O4 annealed at 600 °C with a molar ratio of 1:3 showed the highest photocatalytic degradation of methylene blue. Interestingly close to 99% degradation in less than 60 min of collected sunlight illumination has been achieved indicating maximum photocatalytic activity under investigation. This expounding study will open new way of light harvesting in the field of photocatalysis which is different from common praxis.

Learning by Simulations: A New and Effective Pedagogical Approach for Science, Engineering and Technology Students in a Traditional Setting

Using a pedagogic case study in a traditional learning environment, in this paper, the authors demonstrate how an innovative yet practical computer-based simulation of a complex nano device was an effective tool that improved the learning outcomes of academically less-prepared Bachelor of Nanoscience students in an undergraduate engineering course in a rural university. The authors’ case study presented in this paper strongly suggests that innovations in content delivery, and adaptive learning such as via simulations, can transform what it means to educate students in the 21st century. Learning by Simulations: A New and Effective Pedagogical Approach for Science, Engineering and Technology Students in a Traditional Setting

Coexistence of filamentary and homogeneous resistive switching with memristive and meminductive memory effects in Al/MnO2/SS thin film metal–insulator–metal device

In the present investigation, we have experimentally demonstrated the coexistence of filamentary and homogeneous resistive switching mechanisms in single Al/MnO2/SS thin film metal–insulator–metal device. The voltage-induced resistive switching leads to clockwise and counter-clockwise resistive switching effects. The present investigations confirm that the coexistence of both RS mechanisms is dependent on input voltage, charge-flux and time. Furthermore, the non-zero I–V crossing locations and crossovers hysteresis loops suggested that the developed device has memristive and meminductive properties. The memristive and meminductive memory effects are further confirmed by electrochemical impedance spectroscopy. The results suggested that the mem-device dynamics and electrochemical kinetics during different voltage sweeps and sweep rates are responsible for the coexistence of filamentary and homogeneous resistive switching mechanisms as well as memristive and meminductive memory effect in single Al/MnO2/SS metal–insulator–metal device. The coexistence of both RS effects is useful for the development of high-performance resistive memory and electronic synapse devices. Furthermore, the coexistence of memristive and meminductive memory effects is important for the development of adaptive and self-resonating devices and circuits.