Abstract: Fresh water deficiency caused by climate change calls for employing novel measures to ensure safety of drinking water supply. Wireless sensor networks can be used for monitoring hydrological conditions across wide area, allowing flow forecasting and early detection of pollutants. While there are no fundamental technological obstacles to implementation of large area sensor networks, their feasibility is constrained by unit cost of sensing nodes. This paper describes a low-cost pH sensor, intended for use in fresh water monitoring. The sensor was fabricated in a standard thick film process, and an off-the-shelf resistive paste was used as a sensing material. For the fabrication of sensor, RuO2 resistive paste was screen printed on the alumina substrate with silver conducting layer. Test solutions with pH ranging from 2 to 10 were prepared from HCl or KOH solutions. The potential difference between reference and sensing electrode (electromotive force emf of an electrochemical cell) should be proportional to the pH of a solution according to the Nernst equation. The fabricated sensor exhibits Nernstian response to pH. Influence of storage conditions on sensing performance was also investigated.
Abstract: The idea of generating electricity from plastics itself sounds enthralling, but it is equally challenging to achieve in the lab and then take it to the production level. Polymer Solar Cells (PSCs) have the advantage of lower cost and flexibility but they do suffer from problems like low efficiency and smaller service life which is mainly due to limited absorption spectra, poor charge mobility and the degradation of the polymers. A combination of narrow band donor and fullerene derivative is one of the possible approaches to fabricate a working device. In this work, various experimental techniques have been optimised in order to achieve better efficiency of the PSCs in atmospheric condition. Optimized parameters from polymer mixing ratio, spin coating, annealing and others were used to enhance efficiency of device. Parameters were optimized with the help various techniques viz. Viscometer, Thermo Gravity Analysis, UV-vis spectroscopy, Scanning Electron Microscopy and I-V measurement system. We report 0.76% efficiency in these solar cells, which were fabricated in open atmospheric condition. The as-prepared device showed a good performance with an open-circuit voltage (Voc) 0.74 V, short circuit current (Isc) 0.6 mA, a fill factor (FF) of 35%.
Abstract: Recent nanotechnological revolution mandates astonishing imagination about future nanoworld. Nature has ability to create nanobiomolecules which can function in extraordinary way which can be used to produce nanohybrid systems. The opportunity to use such nanobiomolecules in combination of nanomechanical systems for development of novel nanohybrid systems for their various applications needs to explore in further nanotechnological development. F1 ATPase is a subunit of ATP synthase, which is one of the biomolecular structure works on the plasma membrane of the living cell. The reversible function of F1 ATPase gives a counterclockwise rotation of γ shaft by hydrolyzing ATP and the energy released in the form of rotational torque. This rotational torque of F1 ATPase can be used to power the functional movement of nanodevice. This feature article discusses comparisons of various biomolecular motors for their powering capacities, recent developments, presents new discoveries, experimentations on F1 ATPase and its novel imaginary futuristic applications where F1 ATPase could be used as nanobioengine for powering functional nanoworld.
Abstract: Hydrogen fuel cell generates electrical energy from the electrochemical reaction of hydrogen and oxygen with water vapor as a by-product. Polymer Exchange Membrane Fuel Cell (PEMFC) and Direct Methanol Fuel Cell (DMFC) which are normally utilized for portable applications are not only costly due to platinum electrodes, polymer membrane and supply of hydrogen or methanol as a fuel but also not integrable with silicon fabrication technology. Novel fuel cell based on nanoporous silicon (PS) as Metal/nanoPS/silicon Schottky type structure is under development and Open Circuit Voltage (Voc) upto 550 mV with Au as anode catalyst has been reported. Such fuel cell uses nanoporous silicon layer as proton exchange membrane. This type of structure is found to show humidity-voltaic effect i.e. generation of voltage in humid ambient. Humidity-stimulated voltage generation is facilitated by the hydrogen component of water present in the atmosphere. In the present work, our main objective was to improve Voc. We achieved Voc upto 1.118 V by restricting the pore size of nanoporous silicon to 4-5 nm and thickness of the Cu film to 100 nm. These results suggest that this type of fuel cell could be utilized to develop self-powered integrated circuit.
Abstract: Graphene is the thinnest 2-D material which can be regarded as a single layer of graphite. The unique electrical, mechanical and optical properties of graphene can be used in many technological applications. 2-D nanomaterials with semiconducting properties are of great interest since they can be applied in electronics industry. Pure graphene is a zerogap semiconductor or semimetal, since the electron states just cross the Fermi energy. However, the electronic properties of graphene can be tuned by doping boron or nitrogen atoms. Understanding the electronic properties in terms of density of states and band structure of doped graphene is of great relevance today. In our work, we have analyzed the electronic properties of boron and nitrogen doped graphene using Density Functional Theory (DFT). The stability and charge analysis of doped structures have been studied. The Local Density Approximation (LDA) calculations have been used to find the total energies of the structures. In addition to the electronics industry, doped graphene also has great potential to adsorb gas molecules. Therefore, we have analyzed the H2 molecule adsorption in pure, B-doped and N-doped graphene.