@article { ISI:000346266000074, title = {Field emission properties of ZnO nanosheet arrays}, journal = {Applied Physics Letters}, volume = {105}, number = {23}, year = {2014}, month = {DEC}, pages = {233101}, publisher = {AMER INST PHYSICS}, address = {1305 WALT WHITMAN RD, STE 300, MELVILLE, NY 11747-4501 USA}, abstract = {

{Electron emission properties of electrodeposited ZnO nanosheet arrays grown on Indium tin oxide coated glass substrates have been studied. Influence of oxygen vacancies on electronic structures and field emission properties of ZnO nanosheets are investigated using density functional theory. The oxygen vacancies produce unshared d electrons which form an impurity energy state; this causes shifting of Fermi level towards the vacuum, and so the barrier energy for electron extraction reduces. The ZnO nanosheet arrays exhibit a low turn-on field of 2.4 V/mu m at 0.1 mu A/cm(2) and current density of 50.1 mu A/cm(2) at an applied field of 6.4 V/mu m with field enhancement factor

}, issn = {0003-6951}, doi = {10.1063/1.4903271}, author = {Naik, Kusha Kumar and Khare, Ruchita T. and Chakravarty, Disha and More, Mahendra A. and Thapa, Ranjit and Late, Dattatray J. and Rout, Chandra Sekhar} } @article { ISI:000370057200011, title = {Enhanced electron field emission from NiCo2O4 nanosheet arrays}, journal = {Materials Research Express}, volume = {2}, number = {9}, year = {2015}, month = {SEP}, pages = {095011}, publisher = {IOP PUBLISHING LTD}, address = {TEMPLE CIRCUS, TEMPLE WAY, BRISTOL BS1 6BE, ENGLAND}, abstract = {

Electron emission properties of electrodeposited spinel NiCo2O4 nanosheet arrays grown on Ni foam have been studied. The work function of NiCo2O4 was calculated by density functional theory using the plane-wave basis set and used to estimate the field enhancement factor. The NiCo2O4 nanosheet arrays exhibited a low turn-on field of 1.86 V mu m(-1) at 1 mu A cm(-2) and current density of 686 mu A cm(-2) at 3.2 V mu m(-1), with field enhancement factor beta = 1460 and good field emission current stability. The field emission properties of the NiCo2O4 nanosheet arrays showed enhanced performance compared to chemically prepared NiCo2O4 nanosheets. Hence, the nanosheet arrays have great potential as robust high performance vertical structure electron emitters for future flat panel displays and vacuum electronic device applications.

}, keywords = {Density functional theory, field emission, nanosheets, NiCo2O4, spinel}, issn = {2053-1591}, doi = {10.1088/2053-1591/2/9/095011}, author = {Naik, Kusha Kumar and Khare, Ruchita T. and Gelamo, Rogerio V. and More, Mahendra A. and Thapa, Ranjit and Late, Dattatray J. and Rout, Chandra Sekhar} } @article { ISI:000354445900067, title = {Facile synthesis of Ag nanowire-rGO composites and their promising field emission performance}, journal = {RSC Advances}, volume = {5}, number = {52}, year = {2015}, month = {APR}, pages = {41887-41893}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Crystalline, ultra long silver nanowires (Ag NWs), few-layered rGO (reduced graphene oxide) and their rGO-Ag NW nanocomposite have been synthesized using a polyol reflux technique under optimized experimental conditions. The field emission performance of the rGO-Ag NW nanocomposite, rGO and Ag NW emitters was investigated. The turn on field required to draw an emission current density of similar to 1 mA cm(-2) was found to be similar to 5.00, 3.92 and 2.40 V mu m(-1) for the Ag NW, rGO and rGO-Ag NW nanocomposite emitters, respectively. The combined contribution of the sharp edges of the thin graphene sheets and high aspect ratio of the Ag nanowires, and their synergetic effect in the rGO-Ag NW nanocomposite, are responsible for the enhanced field emission behavior. First-principles density functional calculations show that the enhanced field emission may also be due to the overlapping of the electronic structures of the Ag NWs and rGO nanosheets.

}, issn = {2046-2069}, doi = {10.1039/c5ra00308c}, author = {Samantara, Aneeya K. and Mishra, Dillip Kumar and Suryawanshi, Sachin R. and More, Mahendra A. and Thapa, Ranjit and Late, Dattatray J. and Jena, Bikash Kumar and Rout, Chandra Sekhar} } @article { ISI:000346733500087, title = {Field emission properties of spinel ZnCo2O4 microflowers}, journal = {RSC Advances}, volume = {5}, number = {7}, year = {2015}, month = {DEC}, pages = {5372-5378}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

ZnCo2O4 microflowers were synthesized by a simple low temperature hydrothermal route. A single three-dimensional microflower consists of hundreds of self-assembled petals, with a thickness of several nanometers. These microflowers have exceptionally thin edges with a few petal layers. The ZnCo2O4 microflowers appeared to be stable and good field emitters.

}, issn = {2046-2069}, doi = {10.1039/c4ra10246k}, author = {Ratha, Satyajit and Khare, Ruchita T. and More, Mahendra A. and Thapa, Ranjit and Late, Dattatray J. and Rout, Chandra Sekhar} } @article {46445, title = {Core-composite mediated separation of diverse nanoparticles to purity}, journal = {Soft Matter}, volume = {15}, year = {2019}, month = {OCT}, pages = {7787-7794}, type = {Article}, abstract = {

A generalized method for sorting nanoparticles based on their cores does not exist; it is an immediate necessity, and an approach incorporating cost-effectiveness and biocompatibility is in demand. Therefore, an efficient method for the separation of various mixed core-compositions or dissimilar metallic nanoparticles to their pure forms at the nano-bio interface was developed. Various simple core-combinations of monodispersed nanoparticles with dual cores, including silver plus gold, iron oxide plus gold and platinum plus gold, to the complex three-set core-combinations of platinum plus gold plus silver and platinum plus iron plus gold were sorted using step-gradient centrifugation in a sucrose suspension. Viscosity mediated differential terminal velocities of the nanoparticles permitted diversified dragging at different gradients allowing separation. Stability, purity and properties of the nanoparticles during separation were evaluated based on visual confirmation and by employing advanced instrumentations. Moreover, theoretical studies validated our experimental observations, revealing the roles of various parameters, such as the viscosity of sucrose, the density of the particles and the velocity and duration of centrifugation, involved during the separation process. This remarkably rapid, cost-efficient and sustainable strategy can be adapted to separate other cores of nanoparticles for various biomedical research purposes, primarily to understand nanoparticle induced toxicity and particle fate and transformations in natural biotic environments.

}, issn = {1744-683X}, doi = {10.1039/c9sm01571j}, author = {Bhatt, Chandra S. and Nagaraj, Bharathkumar and Ghosh, Deepanjan and Ramasamy, Sureshkumar and Thapa, Ranjit and Marpu, Sreekar B. and Suresh, Anil K.} } @article {46969, title = {Stress-induced electronic structure modulation of manganese-incorporated Ni2P leading to enhanced activity for water splitting}, journal = {ACS Applied Energy Materials}, volume = {3}, year = {2020}, month = {FEB}, pages = {1271-1278}, type = {Article}, abstract = {

The cornerstone of the emerging hydrogen economy is hydrogen production by water electrolysis with concomitant oxygen generation. Incorporating a third element in metal phosphides can tune the crystalline and electronic structure, hence improving the electrocatalytic properties. In this work, Mn-doped Ni2P with varying ratios of Mn and Ni has been explored as excellent catalysts for water splitting. A complete cell made of the best catalyst Ni1.5Mn0.5P electrodes showed low voltage of 1.75 V at a current density of 10 mA cm(-2) due to enhanced electrical conductivity, induction of tensile stress, enhanced electrochemical surface area, and increased electric dipole upon Mn incorporation.

}, keywords = {Electronic Structure, hydrogen evolution reaction, Oxygen Evolution Reaction, phosphides, water splitting}, issn = {2574-0962}, doi = {10.1021/acsaem.9b02097}, author = {Sarkar, Shreya and Dheer, Lakshay and Vinod, C. P. and Thapa, Ranjit and Waghmare, V. Umesh and Peter, Sebastian C.} } @article {49195, title = {Transient Electro-Graphitization of MOFs Affecting the Crystallization of Ruthenium Nanoclusters for Highly Efficient Hydrogen Evolution}, journal = {ADVANCED FUNCTIONAL MATERIALS}, volume = {34}, year = {2024}, month = {AUG}, type = {Journal Article}, keywords = {amorphous ruthenium, crystallization control, graphitic nanostructure}, issn = {1616-301X}, doi = {10.1002/adfm.202315460}, author = {Karim, Golam Masud and Patra, Amalika and Deb, Sujit Kumar and Upadhya, Hemanta and Das, Snehasish and Mukherjee, Priyam and Ahmad, Waleed and Barman, Narad and Thapa, Ranjit and Dambhare, V, Neha and Rath, Arup Kumar and Das, Jaysri and Manna, Uttam and Urkude, Rajashri R. and Oh, Youngtak and Maiti, Uday Narayan} }