A5067535306- Quantum Dots Synthesis And Properties
- Advanced Memory and Neural Computing
- Chalcogenide Semiconductor Thin Films
- Metal complexes synthesis and properties
- Perovskite Materials and Applications
- Ferroelectric and Negative Capacitance Devices
- Semiconductor Quantum Structures and Devices
- Semiconductor materials and devices
- Heat Transfer Mechanisms
- Fish Biology and Ecology Studies
- Heat Transfer and Optimization
- Synthesis and Reactivity of Heterocycles
- Nanofluid Flow and Heat Transfer
- Magnetism in coordination complexes
- Synthesis and Characterization of Heterocyclic Compounds
- Neuroscience and Neural Engineering
- Photoreceptor and optogenetics research
- Porphyrin and Phthalocyanine Chemistry
- Electronic and Structural Properties of Oxides
- Luminescence and Fluorescent Materials
- Solid-state spectroscopy and crystallography
- Neural dynamics and brain function
- DNA and Nucleic Acid Chemistry
- ZnO doping and properties
- RNA and protein synthesis mechanisms
Indian Institute of Science Education and Research Kolkata
2016-2024
Central Inland Fisheries Research Institute
1985-2023
Homi Bhabha National Institute
2023
Institute of Physics, Bhubaneshwar
2023
Madan Mohan Malaviya University of Technology
2018-2021
National Institute of Technology Arunachal Pradesh
2019-2020
Indian Institute of Technology Kanpur
2019
Memorial University of Newfoundland
1987-2018
College of the North Atlantic
2018
TU Dortmund University
2016
This report discusses the electrical characteristics of two-terminal synaptic memory devices capable demonstrating an analog change in conductance response to varying amplitude and pulse-width applied signal. The are based on Mn doped HfO2 material. mechanism behind reconfiguration was studied a unified model is presented explain underlying device physics. then utilized show application these speech recognition. A comparison between 20 nm × sized with that state-of-the-art VLSI SRAM synapse...
Perovskite quantum dots (PQDs) are known to be defect-tolerant, possessing a clean band gap with optically inactive benign defect states. However, we show that there exist significant deep trap states beyond the conduction minimum, although extent of shallow is observed minimal. The minimum seems in PQDs; however, less than even robust CdSe- and InP-based core/alloy-shell QDs. In-depth analyses based on ultrafast transient absorption ultrasensitive single-particle spectroscopic...
There is no literature report of simultaneously achieving near-unity PLQY (ensemble level) and highly suppressed blinking (ultrasensitive single-particle spectroscopy (SPS) in a toxic-metal-free QD. In this Letter we accomplishing (96%) (>80% ON fraction) CuInS2/ZnSeS Core/Alloy-Shell (CAS) addition, (i) gigantic enhancement (from 15% (Core) to 96% (CAS QD)), (ii) ultrahigh stability over 1 year without significant reduction at the ensemble level, (iii) high magnitude (nearly 3 times)...
InP based quantum dots (QDs) are coming in a big way as an alternative to toxic Cd, or Pb QDs. Unlike many literature reports this work, green-yellow-orange-red emitting highly photoluminescent (PLQY high 65%) and photostable InP/ZnSeS core/alloy shell (CAS QDs) have been synthesized using less toxic, air-stable aminophosphine precursor (P(DMA)3). predictions paper, we show that alloyed QDs can be prepared with InCl3 only. We report here the hitherto unobserved quite interesting excitation...
Highly luminescent (photoluminescence quantum yield (PLQY) as high 96%) CdSe-based core/gradient alloy shell/shell (CGASS) dots (QDs) have been synthesized in "one pot" using the reactivity difference between Cd and Zn precursors Se S precursors. This procedure is highly reproducible quite useful for large-scale synthesis. Upon photoexcitation these QDs show a multiexponential excited state decay behavior. Interestingly, with growth of shell overall PL gets faster. All traces fitted well...
CdSe-based core/gradient alloy shell/shell semiconductor quantum dots (CGASS QDs) have been shown to be optically quite superior compared core-shell QDs. However, very little is known about CGASS QDs at the single particle level. Photoluminescence blinking dynamics of four differently emitting (blue (λem = 510), green 532), orange 591), and red 619)) having average sizes <∼7 nm probed in our home-built total internal reflection fluorescence (TIRF) microscope. All samples possess an...
Core/alloy-shell/shell quantum dots (CASS QDs) have been shown to exhibit excitation energy dependent PL efficiency. The magnitude of the normalized transient population has increase more than 5-fold with decreasing energy. For high cooling exciton (predominantly electron) band edge is much slower (rise time ∼526 fs) in comparison low <∼100 fs). Time constant associated dynamics hot electron trapping ∼1 ps. related independent hole ∼35 Truncation obtained from single particle investigation...
This paper aims to simulate the incompressible laminar flow over a two-dimensional (2D) Prism using simpleFoam solver which is part of open-source software OpenFOAM and validate verify obtained aerodynamic forces for Reynold’s no’s 20, 40 60 with previous literature. The length prism set as 1 m. Lift Drag Coefficients were calculated angles attack 0° 10° characteristics are visualized Open-source software, Paraview. streamlines, velocity pressure contours visualized. Also, comparative...
We report the switching dynamics and charge transport studies on Ru/HfO2/TiOx/Ru resistive random access memory devices in low resistance state (LRS), high (HRS), virgin (VRS). The LRS is governed by Ohmic conduction of electrons through local filamentary paths while it a combination Frenkel-Poole emission trap assisted tunneling process HRS VRS. area filament extracted related to compliance current. thickness re-oxidized reset voltage HRS. energy consumed during was analyzed time-scale...
We report the switching characteristics of Mg-doped HfO <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -based ReRAM devices consisting Ru/ Mg:HfO /TiN/W stacks. The concentration Mg dopant was varied from 0% to 20% for four samples show impact on forming voltage. In addition reducing voltage 2.8 1.7 V, doping in also improved repeatability initial device characteristics, and retention. mechanism conduction identified as Frenkel-Poole...
Suppressed blinking has been reported in large (diameter ∼14.1 nm) core/shell InP quantum dots (QDs) under reduced air environment. We report here suppressed with approximately four times smaller ∼3.6 core/alloy-shell/shell QDs ambient atmosphere. The ⟨ON fraction⟩ obtained to be 0.65. Approximately 26% of the single exhibit ON fraction >80%. exponent (1.19) magnitude comparison OFF (1.45) indicates longer events are interrupted by events. event truncation time is ∼1.5 that event, signifying...
The importance of alloy-shelling in optically robust Core/Alloy-Shell (CAS) QDs has been described from structural and energetic aspects. Unlike fluorescent dyes, both Core/Shell (CS) CAS exhibit excitation-energy-dependent photoluminescence quantum yield (PLQY). For CdSe InP (with metal- nonmetal-based alloy-shelling, respectively), with increasing excitation energy, (a) the ultrafast rise-time or relaxation-time to band-edge increases (b) magnitude normalized bleach signal decreases....
Observation of strong deviation photoluminescence excitation curve from absorption especially at lower wavelength range, below 450 nm in case small-sized toxic metal free InP-based core-alloy-shell quantum dots, hints toward interesting exciton dynamics. Photoluminescence yield (PLQY) has been observed to be dependent on the wavelength. Monitoring bleach dynamics employing femtosecond ultrafast pump–probe technique, it could shown that rise time increases with decrease pump 100 fs for 550...
Intrinsic hole trapping as well detrapping have not been observed for any quantum dot (QD) or perovskite nanocrystal (PNC) system. Moreover, amplitude variation of intrinsic (or detrapping) has reported at all QD PNC However, a CuInS2-based core/alloy-shell (CAS) system, (a) both and (b) very significant variations (∼16 to ∼42%) (∼44 23%) observed. Unlike detrimental electron trapping, shown be beneficial, having direct correlation toward increasing PLQY 96%. Simultaneous quite beneficial...
The smallest fluorophore reported in literature to emit the red has a MW > 250 Da. Hereby, we report unique way obtain red, orange emission ultrasmall fluorophores (DEAMB, = 207 Da), (DEAB, 177 respectively. In this exceptional concept, explore charge transfer between meta-oriented donor–acceptor moieties single-benzenic (meta-fluors). Unlike existing red-emitting small-fluorophores, our meta-fluors exhibit an intense Stokes shift (225 nm), solvatochromic (175 and excited-state lifetime (21...
Contrary to the belief of chemistry community, intense charge transfer is observed between meta-oriented donor–acceptor moieties in ultrasmall single-benzenic fluorophores. Red emission any solvent has so far been reported with molecular fluorophores having lowest weight (MW) 252.5 Da; however, we have achieved same a meta-fluorophore an MW only 203.1 Da. nonpolar fluorophore minimum 464.5 Da, but 255.3 Intense Stokes (260 nm) and solvatochromic (160 shifts, high magnitudes fluorescence...
Halide dependent charge carrier dynamics in CsPb(Br/Cl)<sub>3</sub>perovskite nanocrystals.
Aluminium-doped zinc oxide (ZnO : Al) films have been deposited by RF magnetron sputtering on Pyrex glass substrates. The structural, electrical and optical properties of as a function Al concentration studied. Al-doped exhibit high transparency reduction resistivity with increasing concentration. minimum value is found to be ρ = 2.2 × 10−3 Ω cm compared ∼104 cm, for undoped ZnO. band gap observed follow Burstein–Moss shift the increase in doping shows maximum 3.53 eV. Relative variation...
Herein, the instantaneous synthesis of highly crystalline, uniform-sized (
A stereoselective total synthesis of sapinofuranone B is described starting from commercially available l-(+)-diethyl tartrate using a ring-opening reaction, Mitsunobu inversion, and Sonogashira coupling as the key steps.