@article { ISI:000249169900033, title = {Surface-state-mediated electron transfer at nanostructured ZnO multipod/electrolyte interfaces}, journal = {Journal of Physical Chemistry C}, volume = {111}, number = {35}, year = {2007}, month = {SEP}, pages = {13092-13102}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Redox kinetics of cyanoferrate(III) species adsorbed at an n-type ZnO multipod/electrolyte interface is explored using electrochemical techniques like cyclic voltammetry and impedance spectroscopy. The electrochemical impedance results are analyzed using a fluctuating energy level model, assuming isoenergetic tunneling of majority carriers through the Helmholtz layer. A shift in the slope of Mott-Schottky plots (C-sc(-2) versus E) together with evidence from cyclic voltammetry shows that the electron-transfer process is mediated by surface states formed because of the adsorption of ferricyanide ions (as evident from the results of Fourier transform infrared spectroscopy). More significantly, the pH of zero charge (point of zero zeta potential, pzzp) of ZnO multipods is found to be 4.5 (from capacitance vs pH plots) compared to that of bulk ZnO (pH 9.5), which could be explained on the basis of a lowering in the work function of the nanostructured semiconductor and its consequent susceptibility to the formation of surface states. This is in excellent agreement with our earlier observation of ultralow threshold field emission with this material in the light of the linear dependence of pzzp with work function of the electrode material. The flat-band potential of the nanostructures is found to be 200 mV more negative than that reported for bulk n-type ZnO electrodes, indicating a higher doping density in the former. A three-dimensional mapping of charge distribution in the surface states is attempted by correlating the capacitance response of the system subjected to a sinusoidal potential modulation to the semiconductor electrode with that resulting from a systematic variation of the redox potential of the dissolved acceptor (achieved by varying the pH of the electrolyte) which further reveals the polyenergetic nature of the surface states.

}, issn = {1932-7447}, doi = {10.1021/jp072695x}, author = {Parthasarathy, Meera and Ramgir, Niranjan S. and Sathe, Bhaskar R. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K.} } @article { ISI:000250647000072, title = {Template-assisted synthesis of ruthenium oxide nanoneedles: electrical and electrochemical properties}, journal = {Journal of Physical Chemistry C}, volume = {111}, number = {44}, year = {2007}, month = {NOV}, pages = {16593-16600}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We here demonstrate the formation of bundles of RuO2 nanoneedles (ca. 100 nm diameter) by a templateassisted electrodeposition from aqueous RuCl3 solution under potentiostatic conditions at room temperature. Cyclic voltammetric measurements in 0.5 M H2SO4 show significantly higher redox-related charging behavior for the RuO2 nanoneedles compared to that of the commercial sample, which is also supported by the electrochemical impedance data. A comparison of the specific capacitance reveals a higher value for nanoneedles (3 F/g instead of 0.4 F/g for the bulk), which has been explained on the basis of enhanced reactivity. More interestingly, electrical transport measurements reveal a transition from metallic to semiconducting behavior especially at low-temperature caused by an impurity scattering mechanism. We anticipate that the present simple route for the fabrication of RuO2 nanostructures will be useful to exploit their potentials in various fields such as electrocatalysis, nanoelectronics, and more importantly for designing supercapacitors.

}, issn = {1932-7447}, doi = {10.1021/jp0744836}, author = {Subhramannia, Mahima and Balan, Beena K. and Sathe, Bhaskar R. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K.} } @article { ISI:000257271600056, title = {Electrochemical sensing of sulphur dioxide: a comparison using dodecanethiol and citrate capped gold nanoclusters}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {8}, number = {6}, year = {2008}, month = {JUN}, pages = {3184-3190}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

A comparison of cyclic voltammograms of dodecanethiol (DDT) capped Au nanoclusters (5.0 +/- 0.5 nm) and trisodium citrate (Cit) capped Au nanoclusters (similar to 10-15 nm) modified glassy carbon electrode shows a dramatic variation in the current when exposed to a small amount of sulphur dioxide. This is explained using the electrocatalytic properties of Au nanoclusters towards the oxidation of SO2, thus facilitating the fabrication of electrochemical sensors for the detection of SO2. The intrinsic redox changes observed for gold nanocluster-modified glassy carbon electrodes disappear on passing SO2, despite a dramatic current increase, which indeed scales up with the amount of dissolved SO2. Interestingly, a complete rejuvenation of the redox behavior of gold is also observed on subsequent removal of SO2 from the solution by passing pure nitrogen for 15 minutes. Further, these nanoclusters when characterized with X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) after SO2 passage reveal a variety of SO2 adsorption modes on gold surface. XP spectra also show a shift of 1.03 eV towards higher binding energy indicating a strong adsorption of SO2 gas, while FTIR gives conclusive evidence for the interaction of SO2 with gold nanoparticles.

}, keywords = {cyclic voltammetry, Fourier transform infrared spectroscopy, monolayer protected gold nanoclusters (Au-MPCs), SO2 sensor, X-ray photoelectron spectra}, issn = {1533-4880}, doi = {10.1166/jnn.2008.094}, author = {Sathe, Bhaskar R. and Risbud, Mandar S. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K.} } @article { ISI:000257231200057, title = {Enhanced field emission from hexagonal rhodium nanostructures}, journal = {Applied Physics Letters}, volume = {92}, number = {25}, year = {2008}, month = {JUN}, pages = {253106}, publisher = {AMER INST PHYSICS}, type = {Article}, address = {CIRCULATION \& FULFILLMENT DIV, 2 HUNTINGTON QUADRANGLE, STE 1 N O 1, MELVILLE, NY 11747-4501 USA}, abstract = {

Shape selective synthesis of nanostructured Rh hexagons has been demonstrated with the help of a modified chemical vapor deposition using rhodium acetate. An ultralow threshold field of 0.72 V/mu m is observed to generate a field emission current density of 4 x 10(-3) mu A/cm(2). The high enhancement factor (9325) indicates that the origin of electron emission is from nanostructured features. The smaller size of emitting area, excellent current density, and stability over a period of more than 3 h are promising characteristics for the development of electron sources. (C) 2008 American Institute of Physics.

}, issn = {0003-6951}, doi = {10.1063/1.2943657}, author = {Sathe, Bhaskar R. and Kakade, Bhalchandra A. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K. and Late, Dattatray J. and More, Mahendra A. and Joag, Dilip S.} } @article { ISI:000255627700001, title = {High-purity synthesis of scrolled mats of multi-walled carbon nanotubes using temperature modulation}, journal = {Carbon}, volume = {46}, number = {4}, year = {2008}, month = {APR}, pages = {567-576}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, type = {Article}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Felt-like mats (6-7 mu m thick) of multimalled carbon nanotubes wrapped into scrolls have been synthesized by chemical vapor deposition from a toluene-ferrocene mixture using a temperature ramp from 680 degrees C to 550 degrees C in hydrogen-argon atmosphere. Thermogravimetric analysis reveals a very low catalyst content of ca. 1.25 wt\% in the as-synthesized sample while, X-ray photo electron and Raman spectroscopies suggest the results matching with that of multiwalled carbon nanotubes. Considering, different time scales of various reactions and the diffusion of different reactants and products a tentative base growth mechanism has been proposed as per the available characterization data in conjunction with possible scrolling effects. Thermal expansion effects could explain a tentative mechanism for rolling action of sheets. Interestingly, electrical conductivity measurements as a function of temperature suggest a semiconducting behavior, despite being governed by different electron transport mechanisms with activation energies of 0.33 and 1.03 meV corresponding to two temperature ranges respectively. Cyclic voltammetry and electrochemical impedance analysis show a reversible redox behavior due to very low catalyst content and an irreversible etching of the Fe catalyst after acid treatment. (C) 2007 Elsevier Ltd. All rights reserved.

}, issn = {0008-6223}, doi = {10.1016/j.carbon.2007.12.020}, author = {Kakade, Bhalchandra A. and Allouche, Hatem and Mahima, Subhramanyam and Sathe, Bhaskar R. and Pillai, Vijayamohanan K.} } @article { ISI:000256178900015, title = {Selective cis-dihydroxylation of olefins using recyclable homogeneous molybdenum acetylide catalyst}, journal = {Journal of Molecular Catalysis A-Chemical}, volume = {285}, number = {1-2}, year = {2008}, month = {APR}, pages = {111-119}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Selective cis-dihydroxylation of various olefins has been carried out using molybdenum acetylide complex CpMO(CO)(3)(C CPh) (1) as catalyst and hydrogen peroxide as an efficient and environmentally benign oxidant. In case of cyclohexene, very high conversion (95\%) and selectivity (86\%) for cis-dihydroxylated product has been achieved using H2O2 as an oxidant and t-butanol as a solvent. cis-Dihydroxylation of other substrates like styrene, a-methyl styrene, limonene and cyclopentene has also been carried out with very high selectivity for diol. The catalyst and intermediate species have been characterized using FT-IR, UV-vis spectral analysis and XPS studies as well as cyclic voltametric studies. These studies suggest that molybdenum oxo-peroxo complex is the catalytically active species. The intermediate blue complex when characterized by ESI MS suggested the formation of dimeric molybdenum complex and XPS and cyclic voltametric studies confirm the presence of mixed valence Mo(V) and Mo(VI) in the reaction intermediate. Based on the characterization results possible mechanism for dihydroxylation is proposed. Interestingly, even though the catalyst is homogeneous; it could be recovered quantitatively by extraction in aqueous phase and recycled five times without any appreciable loss in cyclohexene conversion and selectivity for cis-1,2-cyclohexanediol. (c) 2008 Elsevier B.V. All rights reserved.

}, keywords = {acetylide complex, cis-dihydroxylation, Homogeneous catalysis, Hydrogen peroxide, recyclable}, issn = {1381-1169}, doi = {10.1016/j.molcata.2008.01.034}, author = {Biradar, Ankush V. and Sathe, Bhaskar R. and Shubhangi B. Umbarkar and Dongare, Mohan K.} } @article { ISI:000267498700010, title = {Field emission investigation of single Fe-doped SnO2 wire}, journal = {Solid State Sciences}, volume = {11}, number = {6}, year = {2009}, month = {JUN}, pages = {1114-1117}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

Tin oxide submicronwires doped with Fe element were prepared by the thermal evaporation method. Morphological and structural characterizations revealed wires with sub micron size and crystalline in nature. The field electron emission from the single Fe:SnO2 wire was carried out in conventional field emission microscope. The Fowler-Nordheim plot obtained from I-V characteristics of the wire showed a linear behavior typical that of metal. The field enhancement factor estimated from the slope of the F-N plot is 7455 cm(-1), indicating that the field emission is from nanometric features of the emitter. A current density of 10 A/cm(2) has been obtained at an applied field of 4.845 x 10(3) V/mu m. The field emission current-time record at a current level of 1 mu A for more than 3 h duration is promising for various field emissions based applications. (C) 2009 Published by Elsevier Masson SAS.

}, keywords = {Current stability, Fe doped, field emission, SnO2}, issn = {1293-2558}, doi = {10.1016/j.solidstatesciences.2009.02.011}, author = {Bhise, Ashok B. and Late, Dattatray J. and Sathe, Bhaskar R. and More, Mahendra A. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K. and Joag, Dilip S.} } @article { ISI:000266447600030, title = {Preparation and characterization of rhodium nanostructures through the evolution of microgalvanic cells and their enhanced electrocatalytic activity for formaldehyde oxidation}, journal = {Journal of Physical Chemistry C}, volume = {113}, number = {22}, year = {2009}, month = {JUN}, pages = {9616-9622}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Shape-controlled morphological evolution of nanostructured Rh has been demonstrated with the help of a galvanic displacement reaction using Al in 1 mM aqueous Rh(III) chloride at an open circuit potential 0.99 V and at a temperature of 273 K (room temperature). Nanospheres composed of small nanoparticles of size around 2.9 +/- 0.4 nm having uniform distribution with a FCC pattern have been evolved during the course of the reaction. Electrochemical results coupled with structural and morphological characterization data from transmission electron microscopy (TEM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and cyclic voltammetry (CV) suggested the formation of Rh nanostructures. Considering the role of the potential of substrate Al and Rh and diffusion of reactant and product species toward and from the surface of the Al, we proposed the tentative mechanism for the formation of microgalvanic cell. Significantly, these: rhodium nanostructures exhibit enhanced electrocatalytic activity toward many fuel cell reactions as demonstrated by formaldehyde oxidation in 0.5 M NaOH. The present strategy is expected to be valid for preparing many other similar electrocatalysts (Pt, Au, and Pd) capable of exhibiting such a remarkable size- and shape-dependent reactivity.

}, issn = {1932-7447}, doi = {10.1021/jp901055v}, author = {Sathe, Bhaskar R. and Shinde, Dhanraj B. and Pillai, Vijayamohanan K.} } @article { ISI:000286307300007, title = {Synthesis of Sb-doped SnO2 nanowires and hyperbranched structures}, journal = {Science of Advanced Materials}, volume = {1}, number = {1}, year = {2009}, month = {APR}, pages = {38-43}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

Branched nanostructures of semiconducting materials are of great interest for their potential applications in optoelectronic, photonic devices and sensors. We herein describe a facile single-step chemical vapor deposition route for the synthesis of Sb-SnO2 hyperbranched nanostructures comprised of elongated nanowires with 30-40 nm diameter and 10-20 Am length. The morphology and structure has been characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), selective area electron diffraction (SAED), and powder X-ray diffraction (XRD). Also, a possible mechanism is proposed for the growth of nanowires into the hyperbranched form on the basis of the substrate effect, the role of Au nanoparticles, and the effect of Sb doping on specific morphology evolution. Interestingly, electrical conductivity measurements as a function of temperature suggest a semiconducting behavior, despite being governed by different electron-transport mechanisms with activation energies of 0.55 and 0.17 eV, which correspond to pure SnO2 and Sb-SnO2 nanowires, respectively. A precise control over the operating parameters not only envisages custom-designed, branched structures by a simple and economical route but also offers an alternative method to the expensive and tedious nanofabrication techniques for industrial applications.

}, keywords = {Au Nanoparticles, chemical vapor deposition, Sb-SnO2 Hyperbranched Nanostructures}, issn = {1947-2935}, doi = {10.1166/sam.2009.1006}, author = {Sathe, Bhaskar R. and Patil, Mrudula and Walke, Pravin S. and Vivek, J. P. and Lele, Ashish K. and Pillai, Vijayamohanan K. and Mulla, Imtiaz S.} } @article { ISI:000278592400024, title = {Effect of Fe3O4 on morphology of Fe-SnO2 hyperbranched heterostructures}, journal = {Chemical Physics Letters}, volume = {493}, number = {1-3}, year = {2010}, month = {JUN}, pages = {121-125}, publisher = {ELSEVIER SCIENCE BV}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

A simple modified thermal evaporation technique is employed for the synthesis of microstructured Fe:SnO2 system and their plausible growth mechanism has been proposed based on the results from various characterization techniques. Such structures grow in two steps; initially, growth of Fe core takes place from Fe3O4 source which acts as nucleating site for SnO2 growth on its surface as per the vapor-liquid- solid progression. Moreover, the composition of Fe/Sn source and temperature are found to have key roles in governing their morphology. XPS studies clearly demonstrate the presence of Fe species, which acts as a catalyst along with source for hetero-structure growth with SnO2. (C) 2010 Published by Elsevier B.V.

}, issn = {0009-2614}, doi = {10.1016/j.cplett.2010.05.019}, author = {Sathe, Bhaskar R. and Walke, Pravin S. and Mulla, Imtiaz S. and Pillai, Vijayamohanan K.} } @article { ISI:000280514500009, title = {Synthesis of Rh-carbon nanotube based heterostructures and their enhanced field emission characteristics}, journal = {Chemical Communications}, volume = {46}, number = {31}, year = {2010}, month = {JUL}, pages = {5671-5673}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

Selective decoration of Rh nanospheres on acid functionalized carbon nanotubes has been demonstrated using Al as a sacrificial substrate. Remarkable field emission has been observed for this heterostructure as a high current density of 170 mu A cm(-2) is generated at an ultra-low threshold of 300 V mu m(-1), compared to much smaller values for Rh nanospheres and carbon nanotubes separately.

}, issn = {1359-7345}, doi = {10.1039/c0cc01532f}, author = {Sathe, Bhaskar R. and Kakade, Bhalchandra A. and Kushwaha, Ajay and Aslam, Mohammed and Pillai, Vijayamohanan K.} } @article { ISI:000287924700049, title = {Enhanced electrocatalytic performance of interconnected Rh nano-chains towards formic acid oxidation}, journal = {Energy \& Environmental Science}, volume = {4}, number = {3}, year = {2011}, month = {MAR}, pages = {1029-1036}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A chain-like assembly of rhodium nanoparticles (5-7 nm mean diameter) has been synthesized from rhodium chloride with the help of polydentate molecules like tartaric and ascorbic acids (1 : 3 in mM scale) as capping agents at room temperature. Subsequent characterization using transmission electron microscopy, X-ray diffraction and X-ray photoelectron spectroscopy reveals a unique inter-connected network like features, while their electrochemical behavior using cyclic voltammetry and current-time transient suggests potential applications as electrocatalysts in fuel cells. A significant negative shift in the onset potential as well as higher anodic peak current density for formic acid oxidation on Rh-tartaric acid (Rh-TA) as compared to that of bulk Rh metal confirms their higher electrocatalytic activity. Interestingly, the enhancement factor (R) with respect to that of bulk metallic Rh towards formic acid oxidation ranges up to 2000\% for Rh-TA and 1200\% for Rh-AA (Rh-ascorbic acid) respectively. The composition of Rh nano-chains has been further analyzed with thermogravimetry and Fourier transform infra-red spectroscopy to demonstrate the importance of controlling the chain topology using polyfunctional organic molecules. These findings open up new possibilities for tailoring nanostructured electrodes with potential benefits since the development of a better electrocatalysts for many fuel cell reactions continues to be an important challenge.

}, issn = {1754-5692}, doi = {10.1039/c0ee00219d}, author = {Sathe, Bhaskar R. and Balan, Beena K. and Pillai, Vijayamohanan K.} } @article { ISI:000292113700065, title = {Novel catalyst-free synthesis of vertically aligned silicon nanowire-carbon nanotube heterojunction arrays for high performance electron field emitters}, journal = {Chemical Communications}, volume = {47}, number = {27}, year = {2011}, month = {JUN}, pages = {7785-7787}, publisher = {ROYAL SOC CHEMISTRY}, address = {THOMAS GRAHAM HOUSE, SCIENCE PARK, MILTON RD, CAMBRIDGE CB4 0WF, CAMBS, ENGLAND}, abstract = {

A novel, catalyst-free strategy for the direct synthesis of vertically aligned silicon nanowire-carbon nanotube (SiNW-CNT) heterojunction arrays is presented. Such a heterojunction with the junction area in the nanoscale displays enhanced field emission characteristics at low turn-on field, with a nearly three times increase in the field enhancement factor.

}, issn = {1359-7345}, doi = {10.1039/c1cc12243f}, author = {Kale, Vinayak S. and Sathe, Bhaskar R. and Kushwaha, Ajay and Aslam, Mohammed and Shelke, Manjusha V.} } @article { ISI:000315172400021, title = {Significant enhancement of formic acid oxidation using rhodium nanostructures}, journal = {Journal of Nanoscience and Nanotechnology}, volume = {12}, number = {12}, year = {2012}, month = {DEC}, pages = {8994-8998}, publisher = {AMER SCIENTIFIC PUBLISHERS}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

The electrocatalytic activity of as-synthesized shape selective Rh nanostructures has been demonstrated using cyclic voltammetry, revealing unique shape-dependant performance towards HCOOH oxidation. interestingly, the enhancement factor (R) for different shapes of Rh with respect to that of commercial Rh towards formic acid oxidation ranges up to 20,000\% for cubes as compared to 17,500\% for pyramids and 11,000\% for hexagons respectively. Mechanistic pathway for comparatively better sensitivity of cubes as compared to other shapes has been correlated with the results of X-ray diffraction.

}, keywords = {electrocatalysis, Formic Acid Oxidation, Preferential Growth, Rhodium Nanostructures}, issn = {1533-4880}, doi = {10.1166/jnn.2012.6735}, author = {Balan, Beena K. and Sathe, Bhaskar R.} } @article {45445, title = {Biomass-mediated synthesis of Cu-doped TiO2 nanoparticles for improved-performance lithium-ion batteries}, journal = {ACS Omega}, volume = {3}, year = {2018}, month = {OCT}, pages = {13676-13684}, type = {Article}, abstract = {

Pure TiO2 and Cu-doped TiO2 nanoparticles are synthesized by the biomediated green approach using the Bengal gram bean extract. The extract containing biomolecules acts as capping agent, which helps to control the size of nanoparticles and inhibit the agglomeration of particles. Copper is doped in TiO2 to enhance the electronic conductivity of TiO2 and its electrochemical performance. The Cu-doped TiO2 nanoparticle-based anode shows high specific capacitance, good cycling stability, and rate capability performance for its envisaged application in lithium-ion battery. Among pure TiO2, 3\% Cu-doped TiO2, and 7\% Cu-doped TiO2 anode, the latter shows the highest capacity of 250 mAh g(-1) (97.6\% capacity retention) after 100 cycles and more than 99\% of coulombic efficiency at 0.5 A g(-1) current density. The improved electrochemical performance in the 7\% Cu-doped TiO2 is attributed to the synergetic effect between copper and titania. The results reveal that Cu-doped TiO2 nanoparticles might be contributing to the enhanced electronic conductivity, providing an efficient pathway for fast electron transfer.

}, doi = {10.1021/acsomega.8b01903}, author = {Kashale, Anil A. and Dwivedi, Pravin K. and Sathe, Bhaskar R. and Shelke, Manjusha V. and Chang, Jia-Yaw and Ghule, Anil V.} } @article {46044, title = {Superior humidity sensor and photodetector of mesoporous ZnO nanosheets at room temperature}, journal = {Sensors and Actuators B-Chemical}, volume = {293}, year = {2019}, month = {AUG}, pages = {83-92}, type = {Article}, abstract = {

Miniaturized sensor technology is vastly demanding multifunctional materials to fulfill many requirements simultaneously; instead of integrating various sensors into a single device. Efficient operation of these miniaturized sensors at room temperature is highly feasible and cost-effective. The humidity sensing and photodetection is precise merit of sensing in special usage like artificial skin. Sensitivity enhancement in both humidity and photodetection required the high surface area for adsorption as well as a high charge transfer mechanism. The two dimensional (2D) zinc oxide nanosheets (ZnO NS) is the ultimate structure for dimensionally confined transport properties owing to the specific surface atomic configuration that results in high sensitivity, low operating temperature, fast response and recovery, and improved selectivity. Furthermore, introducing porosity into 2D nanostructures has opened new opportunities to enhance the efficiency of sensors and detectors via increasing large surface area and tunable physical and chemical properties. Here we report preparation of mesoporous and highly crystalline 2D ZnO NS by a single step, template free, cost-effective chemical method. The structural and morphological characterizations of ZnO NS are carried out using XRD, FESEM, XPS, TEM respectively. The high-resolution TEM images emphasize sheet-like morphology with a thickness of around 18-22 nm. Further the mesoporous ZnO NS (MZNS) with the pore size between 5-10 nm are achieved by simple heat-treatment. XPS and PL study is confirming the oxygen deficiency in MZNS. The MZNS exhibits an excellent responsivity than PZNS with a fast response and rapid recovery time of 25 s and 5 s respectively along with good cyclic stability which is highly crucial for smart humidity sensor. Furthermore, it considerably enhances photo-sensor performance than pristine ZnO NS (PZNS) with (similar to)1 s response time as well as (similar to)1 s recovery time along with better stability. These promising results illustrate the great potential of MZNS for next-generation humidity sensors and photodetectors.

}, keywords = {humidity sensor, Mesoporous, nanosheets, Photo-detector}, issn = {0925-4005}, doi = {10.1016/j.snb.2019.04.086}, author = {Gupta, Shobhnath P. and Pawbake, Amit S. and Sathe, Bhaskar R. and Late, Dattatray J. and Walke, Pravin S.} }