@article { ISI:000228412500017, title = {Structural rationalisation of co-crystals formed between trithiocyanuric acid and molecules containing hydrogen bonding functionality}, journal = {Chemistry - A European Journal}, volume = {11}, number = {8}, year = {2005}, note = {Symposium on Chemistry-A European Conference - Stimulating Concepts in Chemistry, Inst Sci Ingenierie Supramoleculaires, Strasbourg, FRANCE, APR 15, 2005}, month = {APR}, pages = {2433-2439}, publisher = {WILEY-BLACKWELL}, type = {Article}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Crystallisation of trithiocyanuric acid (TTCA) from various organic solvents that have hydrogen bonding capability (acetone, 2-butanone, dimethylformamide, dimethyl sulfoxide, methanol and acetonitrile) leads to the formation of co-crystals in which the solvent molecules are incorporated together with TTCA in the crystal structure. Structure determination by single-crystal X-ray diffraction reveals that these co-crystals can be classified into different groups depending upon the topological arrangement of the TTCA molecules in the crystal structure. Thus, three different types of single-tape arrangements of TTCA molecules and one type of double-tape arrangement of TTCA molecules are identified. In all co-crystals, hydrogen-bonding interactions are formed through the involvement of N-H bonds of TTCA molecules in these tapes and the other molecule in the co-crystal. Detailed rationalisation of the structural properties of these co-crystals is presented.

}, keywords = {crystal engineering, hydrogen bonds, nitrogen heterocycles, structure elucidation}, issn = {0947-6539}, doi = {10.1002/chem.200400340}, author = {Ahn, Sung-Hoon and PrakashaReddy, J. and Kariuki, B. M. and Chatterjee, S. and Ranganathan, A. and Pedireddi, V. R. and Rao, C. N. R. and Harris, Kenneth D. M.} } @article {43232, title = {Sensing behavior of atomically thin-layered MoS2 transistors}, journal = {ACS Nano}, volume = {7}, year = {2013}, month = {JUN}, pages = {4879-4891}, abstract = {Most of recent research on layered chalcogenides is understandably focused on single atomic layers. However, it is unclear if single-layer units are the most ideal structures for enhanced gas solid interactions. To probe this issue further, we have prepared large-area MoS2 sheets ranging from single to multiple layers on 300 nm SiO2/Si substrates using the micromechanical exfoliation method. The thickness and layering of the sheets were identified by optical microscope, invoking recently reported specific optical color contrast, and further confirmed by AFM and Raman spectroscopy. The MoS2 transistors with different thicknesses were assessed for gas-sensing performances with exposure to NO2, NH3, and humidity in different conditions such as gate bias and light Irradiation. The results show that, compared to the single-layer counterpart, transistors of few MoS2 layers exhibit excellent sensitivity, recovery, and ability to be manipulated by gate bias and green light. Further, our ab initio DFT calculations on single-layer and bilayer MoS2 show that the charge transfer is the reason for the decrease in resistance in the presence of applied field.}, doi = {10.1021/nn400026u}, author = {Late, Dattatray J. and Huang, Yi-Kai and Liu, Bin and Acharya, Jagaran and Shirodkar, Sharmila N. and Luo, Jiajun and Yan, Aiming and Charles, Daniel and Waghmare, Umesh V. and Dravid, Vinayak P. and Rao, C. N. R.} } @article { ISI:000337521700009, title = {Thermal expansion, anharmonicity and temperature-dependent Raman spectra of single- and few-layer MoSe2 and WSe2}, journal = {ChemPhysChem}, volume = {15}, number = {8}, year = {2014}, month = {JUN}, pages = {1592-1598}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

We report the temperature-dependent Raman spectra of single-and few-layer MoSe2 and WSe2 in the range 77-700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high-resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A(2u)(2) mode is larger than that of the A(1g) mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single-layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single-layer MoSe2 are larger than those of the same modes in single-layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi-harmonic approximation, with inputs from first-principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman-active mode A(1g) in MoS2 and MoSe2 arises essentially from the difference in their strainphonon coupling.

}, issn = {1439-4235}, doi = {10.1002/cphc.201400020}, author = {Late, Dattatray J. and Shirodkar, Sharmila N. and Waghmare, Umesh V. and Dravid, Vinayak P. and Rao, C. N. R.} } @article { ISI:000357498200004, title = {Combined experimental and theoretical study of the structural, electronic and vibrational properties of bulk and few-layer Td-WTe2}, journal = {Journal of Physics-Condensed Matter}, volume = {27}, number = {28}, year = {2015}, month = {JUL}, pages = {285401}, publisher = {IOP PUBLISHING LTD}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {

The recent discovery of non-saturating giant positive magnetoresistance has aroused much interest in Td-WTe2. We have investigated structural, electronic and vibrational properties of bulk and few-layer Td-WTe2 experimentally and theoretically. Spin-orbit coupling is found to govern the semi-metallic character of Td-WTe2 and its structural link with the metallic 1 T form provides an understanding of its structural stability. There is a metal-to-insulator switch-over in the electrical conductivity and a change in the sign of the Seebeck coefficient around 373 K. Lattice vibrations of Td-WTe2 have been analyzed using first-principles calculations. Out of the 33 possible zone-center Raman active modes, five distinct Raman bands are observed around 112, 118, 134, 165 and 212 cm(-1) in bulk Td-WTe2. Based on symmetry analysis and calculated Raman tensors, we assign the intense bands at 165 cm(-1) and 212 cm(-1) to the A(1){\textquoteright} and A(1){\textquoteright}{\textquoteright} modes, respectively. Most of the Raman bands stiffen with decreasing thickness, and the ratio of the integrated intensities of the A(1){\textquoteright}{\textquoteright} to A(1){\textquoteright} bands decreases in the few-layer sample, while all the bands soften in both the bulk and few-layer samples with increasing temperature.

}, keywords = {Raman spectroscopy, Td-structure, tungsten ditelluride}, issn = {0953-8984}, doi = {10.1088/0953-8984/27/28/285401}, author = {Jana, Manoj K. and Singh, Anjali and Late, Dattatray J. and Rajamathi, Catherine R. and Biswas, Kanishka and Felser, Claudia and Waghmare, Umesh V. and Rao, C. N. R.} } @article { ISI:000377203300030, title = {Electronic structure and properties of layered gallium telluride}, journal = {Chemical Physics Letters}, volume = {651}, year = {2016}, month = {MAY}, pages = {148-154}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Layer-dependent electronic structure and properties of gallium monochalcogenides, GaX where X=S, Se, Te, have been investigated using first-principles calculations based on various functionals, with a motivation to assess their use in photocatalytic water splitting. Since hydrogen evolution by water splitting using visible light provides a promising way for solar energy conversion, both theoretical and experimental studies have been carried out on the photochemical hydrogen evolution by GaTe. We also present the Raman spectra of GaTe examined by both theory and experiment. (C) 2016 Elsevier B.V. All rights reserved.

}, issn = {0009-2614}, doi = {10.1016/j.cplett.2016.03.045}, author = {Shenoy, U. Sandhya and Gupta, Uttam and Narang, Deepa S. and Late, Dattatray J. and Waghmare, Umesh V. and Rao, C. N. R.} }