Indian Institute of Technology Kharagpur

About: Indian Institute of Technology Kharagpur is a education organization based out in Kharagpur, India. It is known for research contribution in the topics: Computer science & Dielectric. The organization has 16887 authors who have published 38658 publications receiving 714526 citations.

Bifunctional Manganese Ferrite/Polyaniline Hybrid as Electrode Material for Enhanced Energy Recovery in Microbial Fuel Cell.

Abstract: Microbial fuel cells (MFCs) are emerging as a sustainable technology for waste to energy conversion where electrode materials play a vital role on its performance Platinum (Pt) is the most common material used as cathode catalyst in the MFCs However, the high cost and low earth abundance associated with Pt prompt the researcher to explore inexpensive catalysts The present study demonstrates a noble metal-free MFC using a manganese ferrite (MnFe2O4)/polyaniline (PANI)-based electrode material The MnFe2O4 nanoparticles (NPs) and MnFe2O4 NPs/PANI hybrid composite not only exhibited superior oxygen reduction reaction (ORR) activity for the air cathode but also enhanced anode half-cell potential upon modifying carbon cloth anode in the single-chambered MFC This is attributed to the improved extracellular electron transfer of exoelectrogens due to Fe(3+) in MnFe2O4 and its capacitive nature The present work demonstrates for the first time the dual property of MnFe2O4 NPs/PANI, ie, as cathode catalyst and an anode modifier, thereby promising cost-effective MFCs for practical applications

CMOS integration of inkjet-printed graphene for humidity sensing.

Abstract: We report on the integration of inkjet-printed graphene with a CMOS micro-electro-mechanical-system (MEMS) microhotplate for humidity sensing. The graphene ink is produced via ultrasonic assisted liquid phase exfoliation in isopropyl alcohol (IPA) using polyvinyl pyrrolidone (PVP) polymer as the stabilizer. We formulate inks with different graphene concentrations, which are then deposited through inkjet printing over predefined interdigitated gold electrodes on a CMOS microhotplate. The graphene flakes form a percolating network to render the resultant graphene-PVP thin film conductive, which varies in presence of humidity due to swelling of the hygroscopic PVP host. When the sensors are exposed to relative humidity ranging from 10–80%, we observe significant changes in resistance with increasing sensitivity from the amount of graphene in the inks. Our sensors show excellent repeatability and stability, over a period of several weeks. The location specific deposition of functional graphene ink onto a low cost CMOS platform has the potential for high volume, economic manufacturing and application as a new generation of miniature, low power humidity sensors for the internet of things.

Tunable Direct Bandgap Optical Transitions in MoS2 Nanocrystals for Photonic Devices

Abstract: Highly luminescent MoS2 nanocrystals (NCs) with controlled size distribution have been achieved using a simple yet inexpensive and impurity free sono-chemical exfoliation method followed by gradient centrifugation. The size of nanocrystals could be varied within the diameter range of ∼4 to 70 nm. Typical MoS2 nanocrystal has exhibited high crystalline quality with 0.25 nm lattice fringe spacing for (002) planes for 2-H phase of MoS2. Raman spectra has revealed that both out-of-plane and in-plane vibrational modes are stiffen due to the edge effect of MoS2 NCs. The size tunable optical properties of MoS2 NCs have been investigated by optical absorption and photoluminescence spectroscopy. The coexistence of direct band gap emission from 2D MoS2 nanosheets and quantum confined nanocrystals has been achieved. A strong and tunable photoluminescence (560–518 nm) emission due to the quantum size effect of tiny NCs below a critical dimension is reported for the first time. The photocurrent measurement of the Au/M...

Intramolecular Charge Transfer and Solvation Dynamics of Coumarin 152 in Aerosol-OT, Water-Solubilizing Reverse Micelles, and Polar Organic Solvent Solubilizing Reverse Micelles

Abstract: The relative retardation of intramolecular charge transfer (ICT) and the solvation dynamics of coumarin 152 in pure AOT, water, methanol, acetonitrile, and formamide reverse micelles have been investigated using picosecond time-resolved emission spectroscopy. The rate of ICT has been retarded almost 7 times at w0 = 4 and 4 times at w0 = 32 compared to that in pure water. The rate of retardation of ICT is also observed in the methanol and acetonitrile reverse micelles in comparison to that in pure methanol and acetonitrile. In pure AOT, the solvation time is 12.22 ns, but at w0 = 4 of water reverse micelles the solvation time is 7.27 ns. The slow dynamics in methanol, acetonitrile, and formamide reverse micelles is also observed. The relative retardation of the ICT rate is much smaller compared to the several thousand fold decrease in the solvation dynamics in the pool of the reverse micelles. The w dependency of solvation time is observed for water and methanol reverse micelles, but it is little for aceto...