@article { ISI:000263018200028, title = {Chemical bath deposition of CdS quantum dots on vertically aligned ZnO nanorods for quantum dots-sensitized solar cells}, journal = {Electrochemistry Communications}, volume = {11}, number = {1}, year = {2009}, month = {JAN}, pages = {103-106}, publisher = {ELSEVIER SCIENCE INC}, address = {360 PARK AVE SOUTH, NEW YORK, NY 10010-1710 USA}, abstract = {

Formation of US quantum dots (Q dots) on the vertically aligned ZnO nanorods electrode was carried out by chemical bath deposition. The diameter and thickness of ZnO nanorods are similar to 100-150 nm and similar to 1.6 mu m, respectively, and CdS Q dots on ZnO nanorods have a diameter of smaller than 15 nm. In application of the Q dots-sensitized solar cells, composite film exhibited a power conversion efficiency of 0.54\% under air mass 1.5 condition (80 mW/cm(2)), and incident-photon-to-current conversion efficiency showed 18.6\%. (c) 2008 Elsevier B.V. All rights reserved.

}, keywords = {Chemical bath deposition, Photosensitization, quantum dots, solar cells, Wet-chemical process}, issn = {1388-2481}, doi = {10.1016/j.elecom.2008.10.042}, author = {Lee, Wonjoo and Min, Sun Ki and Dhas, Vivek V. and Ogale, Satishchandra B. and Han, Sung-Hwan} } @article { ISI:000308879000041, title = {Electrochemical preparation of luminescent graphene quantum dots from multiwalled carbon nanotubes}, journal = {Chemistry-A European Journal}, volume = {18}, number = {39}, year = {2012}, month = {SEP}, pages = {12522-12528}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Green luminescent, graphene quantum dots (GQDs) with a uniform size of 3, 5, and 8.2(+/- 0.3) nm in diameter were prepared electrochemically from MWCNTs in propylene carbonate by using LiClO4 at 90?degrees C, whereas similar particles of 23(+/- 2) nm were obtained at 30?degrees C under identical conditions. Both these sets of GQDs displayed a remarkable quantum efficiency of 6.3 and 5.1?\%, respectively. This method offers a novel strategy to synthesise size-tunable GQDs as evidenced by multiple characterisation techniques like transmission and scanning electron microscopy, atomic force microscopy, Raman spectroscopy and X-ray diffraction (XRD). Photoluminescence of these GQDs can be tailored by size variation through a systematic change in key process parameters, like diameter of carbon nanotube, electric field, concentration of supporting electrolyte and temperature. GQDs are promising candidates for a variety of applications, such as biomarkers, nanoelectronic devices and chemosensors due to their unique features, like high photostability, biocompatibility, nontoxicity and tunable solubility in water.

}, keywords = {electrochemical synthesis, graphene, Nanostructures, photoluminescence, quantum dots}, issn = {0947-6539}, doi = {10.1002/chem.201201043}, author = {Shinde, Dhanraj B. and Pillai, Vijayamohanan K.} } @article { ISI:000303281200026, title = {In vitro enzyme mediated synthesis of metal sulfide nanoparticles: control of particle size of CdS, Ni7S6, PbS, Co3S4 nanoparticles using synthetic peptides}, journal = {Science of Advanced Materials}, volume = {4}, number = {1}, year = {2012}, month = {JAN}, pages = {179-186}, publisher = {AMER SCIENTIFIC PUBLISHERS}, type = {Article}, address = {26650 THE OLD RD, STE 208, VALENCIA, CA 91381-0751 USA}, abstract = {

We report the use of enzyme sulfite reductase for the in vitro synthesis of technologically important metal sulfide quantum dots viz. Co3S4, PbS and Ni7S6. Also we report the use of synthetic peptides to control the particle size of the above metal sulfide quantum dots in addition to CdS, synthesized using enzyme. Sulfite reductase when incubated with aqueous CdCl2, or Co(NO3)(3) or NiCl2 or Pb(NO3)(2), and Na2SO3 in the presence of the appropriate capping peptide resulted in the synthesis of particle size controlled CdS, Co3S4, Ni7S6, or PbS quantum dots respectively. These, enzyme mediated synthesized and size controlled metal sulfide quantum dots, were characterized using Absorbance and photoluminescence spectrometry, X-ray diffraction, X-ray photoelectron spectroscopy and High resolution-transmission electron microscopy.

}, keywords = {Capping Peptide, Enzyme, Metal Sulfide Nanoparticles, quantum dots, Size Control, Sulfite Reductase}, issn = {1947-2935}, doi = {10.1166/sam.2012.1270}, author = {Ansary, Abu Ayoobul and Khan, Muhammed I. and Gaikwad, Sushama M.} } @article { ISI:000315209900016, title = {Electrochemical resolution of multiple redox events for graphene quantum dots}, journal = {Angewandte Chemie-International Edition}, volume = {52}, number = {9}, year = {2013}, month = {JAN}, pages = {2482-2485}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, keywords = {charging energy, differential pulse voltammetry, graphene, quantum dots, single-electron transfer}, issn = {1433-7851}, doi = {10.1002/anie.201208904}, author = {Shinde, Dhanraj B. and Pillai, Vijayamohanan K.} } @article {46366, title = {Water electrolysis with a conducting carbon cloth: subthreshold hydrogen generation and superthreshold carbon quantum dot formation}, journal = {ChemSusChem}, volume = {7}, year = {2014}, month = {MAR}, pages = {883-889}, type = {Article}, abstract = {

A conducting carbon cloth, which has an interesting turbostratic microstructure and functional groups that are distinctly different from other ordered forms of carbon, such as graphite, graphene, and carbon nanotubes, was synthesized by a simple one-step pyrolysis of cellulose fabric. This turbostratic disorder and surface chemical functionalities had interesting consequences for water splitting and hydrogen generation when such a cloth was used as an electrode in the alkaline electrolysis process. Importantly, this work also gives a new twist to carbon-assisted electrolysis. During electrolysis, the active sites in the carbon cloth allow slow oxidation of its surface to transform the surface groups from COH to COOH and so forth at a voltage as low as 0.2V in a two-electrode system, along with platinum as the cathode, instead of 1.23V (plus overpotential), which is required for platinum, steel, or even graphite anodes. The quantity of subthreshold hydrogen evolved was 24mLcm(-2)h(-1) at 1V. Interestingly, at a superthreshold potential (\>1.23V+overpotential), another remarkable phenomenon was found. At such voltages, along with the high rate and quantity of hydrogen evolution, rapid exfoliation of the tiny nanoscale (5-7nm) units of carbon quantum dots (CQDs) are found in copious amounts due to an enhanced oxidation rate. These CQDs show bright-blue fluorescence under UV light.

}, keywords = {Carbon, electrolysis, Hydrogen, photoluminescence, quantum dots}, issn = {1864-5631}, doi = {10.1002/cssc.201300827}, author = {Biswal, Mandakini and Deshpande, Aparna and Kelkar, Sarika and Ogale, Satishchandra} } @article { ISI:000368563000102, title = {Hybrid perovskite quantum nanostructures synthesized by electrospray antisolvent-solvent extraction and intercalation}, journal = {ACS Applied Materials \& Interfaces}, volume = {8}, number = {1}, year = {2016}, month = {JAN}, pages = {854-861}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

Perovskites based on organometal lead halides have attracted great deal of scientific attention recently in the context of solar cells and optoelectronic devices due to their unique and tunable electronic and optical properties. Herein, we show that the use of electrospray technique in conjunction with the antisolventsolvent extraction leads to novel low-dimensional quantum structures (especially 2-D nanosheets) of CH3NH3PbI3- and CH3NH3PbBr3-based layered perovskites with unusual luminescence properties. We also show that the optical bandgaps and emission characteristics of these colloidal nanomaterials can be tuned over a broad range of visible spectral region by compositional tailoring of mixed-halide (I- and Br-based) perovskites.

}, keywords = {2D nanostructure systems, antisolvent-solvent extraction, bandgap tuning, electrospray, nanosheets, perovskite, quantum dots}, issn = {1944-8244}, doi = {10.1021/acsami.5b10208}, author = {Naphade, Rounak and Nagane, Satyawan and Shanker, G. Shiva and Fernandes, Rohan and Kothari, Dushyant and Zhou, Yuanyuan and Padture, Nitin P. and Ogale, Satishchandra} } @article { ISI:000373738000011, title = {Nanoporous graphene enriched with Fe/Co-N active sites as a promising oxygen reduction electrocatalyst for anion exchange membrane fuel cells}, journal = {Advanced Functional Materials}, volume = {26}, number = {13}, year = {2016}, month = {APR}, pages = {2150-2162}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

Here, a simple but efficient way is demonstrated for the preparation of nanoporous graphene enriched with Fe/Co-nitrogen-doped active sites (Fe/Co-NpGr) as a potential electrocatalyst for the electrochemical oxygen reduction reaction (ORR) applications. Once graphene is converted into porous graphene (pGr) by a controlled oxidative etching process, pGr can be converted into a potential electrocatalyst for ORR by utilizing the created edge sites of pGr for doping nitrogen and subsequently to utilize the doped nitrogens to build Fe/Co coordinated centers (Fe/Co-NpGr). The structural information elucidated using both XPS and TOF-SIMS study indicates the presence of coordination of the M-N (M = Fe and Co)-doped carbon active sites. Creation of this bimetallic coordination assisted by the nitrogen locked at the pore openings is found to be helping the system to substantially reduce the overpotential for ORR. A 30 mV difference in the overpotential () with respect to the standard Pt/C catalyst and high retention in half wave potential after 10 000 cycles in ORR can be attained. A single cell of an anion exchange membrane fuel cell (AEMFC) by using Fe/Co-NpGr as the cathode delivers a maximum power density of approximate to 35 mWcm(-2) compared to 60 mWcm(-2) displayed by the Pt-based system.

}, keywords = {electrocatalyst, nitrogen doping, oxygen reduction reaction, porous grapheme, quantum dots}, issn = {1616-301X}, doi = {10.1002/adfm.201504765}, author = {Palaniselvam, Thangavelu and Kashyap, Varchaswal and Bhange, Siddeswar N. and Baek, Jong-Beom and Kurungot, Sreekumar} } @article {48206, title = {CdSe quantum dot-based nanocomposites for ultralow-power memristors}, journal = {ACS Applied Nano Materials}, volume = {5}, year = {2022}, month = {JUN}, pages = {8502-8510}, type = {Article}, abstract = {

The explosion in digital communication with the huge amount of data and the internet of things (IoT) led to the increasing demand for data storage technology with faster operation speed, high-density stacking, nonvolatility, and low power consumption for saving energy. Metal chalcogenide-based quantum dots (QDs) show excellent nonvolatile resistive memory behavior owing to their tunable electronic states and control in trap states by passivating the surface with different ligands. Here, we synthesized high-quality colloidal monodispersed CdSe QDs by the hot injection method. The CdSe QDs were blended with an organic polymer, poly(4-vinylpyridine) (PVP), to fabricate an Al\textbackslashCdSe-PVP\textbackslashAl device. Our device shows excellent bipolar nonvolatile resistive random access memory (RRAM) switching behavior with a high current ON/OFF ratio (I-ON/OFF) of 6.1 x 10(4), and it consumes ultralow power. The charge trapping and detrapping in the potential well formed by the CdSe QD and PVP combination result in resistive switching. This CdSe-PVP-based resistive random access memory (RRAM) device with a high I-ON/OFF, ultrafast switching speed, high endurance, low operating voltage, and long retention period can be used as a high-performance and ultralow-power memristive device.

}, keywords = {memory switching, memristor, metal chalcogenides, nonvolatile, quantum dots}, doi = {10.1021/acsanm.2c01894}, author = {Bera, Jayanta and Betal, Atanu and Sharma, Ashish and Shankar, Uday and Rath, Arup Kumar and Sahu, Satyajit} } @article {48033, title = {Thiocyanate- and thiol-functionalized p-doped quantum dot colloids for the development of bulk homojunction solar cells}, journal = {Energy Technology}, volume = {10}, year = {2022}, month = {SEP}, pages = {2200455}, type = {Article}, abstract = {

Progress in device engineering and surface passivation strategies has led to steady progress in colloidal quantum dot (QD) solar cells. Bulk homojunction (BHJ) device architecture has several advantages over the conventional planar junction in developing QD solar cells. Herein, surface ligand chemistry is utilized to control the doping type and dispersibility of oppositely doped PbS QDs to develop BHJ solar cells. Thiocyanate and thiol ligand combination is introduced to develop p-PbS QD ink, which is blended with halide-passivated n-PbS QDs to build BHJ solar cells. It is shown that BHJ solar cells are benefited from high energy offset and higher hole mobility. This leads to the superior carrier extraction from a thicker active layer without compromising fill factor and open circuit voltage. Power conversion efficiency has reached 10.7\% in 530 nm-thick BHJ solar cells, a 24\% improvement over the best performing planar solar cells. With the help of the 1D solar cell capacitance simulator, it is shown that a 15\% efficient QD solar cell can be realized by further improving the hole mobility above 0.1 cm(2) V-1 s(-1).

}, keywords = {bulk homojunctions, Doping, quantum dots, solar cells, surface functionalization}, issn = {2194-4288}, doi = {10.1002/ente.202200455}, author = {Dambhare, V. Neha and Sharma, Ashish and Mahajan, Chandan and Rath, Arup K.} } @article {48701, title = {Multi-bandgap quantum dots ensemble for near-infrared photovoltaics}, journal = {Energy Technology}, volume = {11}, year = {2023}, month = {JUN}, type = {Article}, abstract = {

Narrow bandgap quantum dots (QDs) are an important class of materials for near-infrared (NIR) optoelectronic devices owing to their size-tunable bandgap and chemical root processing. In photovoltaic applications, NIR QDs could be particularly useful to complement the sub-bandgap transmission loss of NIR solar radiation from perovskite and c-Si solar cells. However, insufficient carrier extraction thickness associated with the narrow NIR excitonic bandwidth of QDs limits the conversion efficacy of the broad NIR solar spectrum. Here, we utilize a multi-bandgap QD ensemble which widens the NIR absorption bandwidth to mimic the broad solar spectrum. A solution-phase ligand passivation strategy is used to control doping properties and energy level alignment of multi-bandgap QDs. We successfully developed bulk-heterojunction solar cells using the multi-bandgap QD ensemble, which yields higher carrier extraction thickness and broader NIR absorption. The gain from NIR absorption and carrier transport resulted in higher short-circuit current generation and power conversion efficiency (PCE) in solar cell devices. The champion device shows 8.73\% PCE under 1.5 AM solar illumination and 7.44\% and 5.05\% PCE for the NIR photons transmitted from perovskite and c-Si layers.

}, keywords = {bulk-heterojunctions, multi-bandgap, near-infrared, quantum dots, solar cells, surface passivation}, issn = {2194-4288}, doi = {10.1002/ente.202201375}, author = {Mahajan, Chandan and Dambhare, Neha V. and Biswas, Arindam and Sharma, Anjali and Shinde, Dipak Dattatray and Rath, Arup K.} }