Arunasish Layek

Arunasish Layek
Adamas University · Chemistry

PhD

About

27
Publications
4,902
Reads
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562
Citations
Additional affiliations
November 2017 - present
Adamas University
Position
  • Professor (Assistant)
Description
  • Single Molecule Spectroscopy and Microscopy, Ultrafast Time Resolved Spectroscopy, Single Molecule Single Particle Super Resolution Catalysis
March 2015 - September 2017
KU Leuven
Position
  • PostDoc Position
Description
  • Single Molecule Catalysis
November 2012 - December 2014
University of Waterloo
Position
  • PostDoc Position
Education
July 2007 - October 2012
Indian Institute of Technology Bombay
Field of study
  • Single Molecule Microscopy and Spectroscopy

Publications

Publications (27)
Article
Full-text available
Photo-luminescence (P-L) intermittency (or blinking) in semiconductor nanocrystals (NCs), a phenomenon ubiquitous to single-emitters, is generally considered to be temporally random intensity fluctuations between “bright” (“On”) and “dark” (“Off”) states. However, individual quantum-dots (QDs) rarely exhibit such telegraphic signals, and yet, a vas...
Article
Nanocrystalline zeolite particles are applied in a wide range of catalytic reactions. Their size, shape, and the distribution of catalytically active sites, significantly varies throughout zeolite batches and within individual particles. This variability leads to a heterogeneous distribution of catalyst performance. Directly investigating the struc...
Preprint
Photo-luminescence intermittency (blinking) in semiconductor nanocrystals (NCs), a phenomenon ubiquitous to single-emitters, is generally considered to be temporally random intensity fluctuations between bright (On) and dark (Off) states. However, individual quantum-dots (QDs) rarely exhibit such telegraphic signal, and yet, the vast majority of si...
Article
Molecular-sized micropores of ZSM-5 zeolite catalysts provide spatial restrictions around catalytic sites that allow for shape-selective catalysis. However, the fact that ZSM-5 has two main pore systems with different geometries is relatively unexploited as a potential source of additional shape selectivity. Here, we use confocal laser-scanning mic...
Article
Full-text available
We report the synthesis of size controlled ZnO and rare-earth doped ZnO nanorods in the sub-10 nm diameter regime. The preferential growth of the nanostructures along the polar c-axis leads to the formation of wurtzite phase ZnO nanorods. The anisotropic growth is the manifestation of 'oriented attachment' kinetics. Photoluminescence measurements r...
Article
We demonstrate the coexistence of Eu(2+) and Eu(3+) in corundum and bixbyite-type colloidal In2O3 nanocrystals. The emission properties of dopants in both oxidation states are determined by their interaction with native defects, and are dramatically different in the two nanocrystal phases. This difference arises from the smaller nanocrystal size an...
Article
Full-text available
Graded interface core-shell nanocrystals (NCs) are being investigated to attain highly luminescent systems and are also anticipated to be “blinking-free” at the single particle level. In the present work, CdSe/ZnSe graded core/shell NCs with varying confinement potential profile are studied at single particle level. The internal structure of NCs is...
Article
Introducing multiple luminescent centers into colloidal nanocrystals is an attractive way to impart new optical properties into this class of materials. Doping disparate ions into specific nanocrystals is often challenging, due to the preferential incorporation of one type of dopant. Here, we demonstrate the coexistence of europium dopants as dival...
Article
We report a quantitative analysis and development of hybrid white-light-emitting nanoconjugates, prepared by functionalizing colloidal γ-Ga 2 O 3 nanocrystals with selected organic fluorophores. Using the Fö rster resonance energy transfer (FRET) formalism, we studied the coupling of native defect states in Ga 2 O 3 nanocrystals, as energy donors,...
Article
Full-text available
Developing new ways of generating white light is of paramount importance for the design of the next generation of smart, energy-efficient lighting sources. Here we report tunable white light emission of hybrid organic–inorganic nanostructures based on colloidal ZnO nanocrystals conjugated with organic fluorophores. These materials act as single nan...
Article
Full-text available
We report the synthesis and study of the photoluminescence properties of colloidal lanthanide(III)-doped Ga 2 O 3 nanocrystals. The Ga 2 O 3 nanocrystal host lattice acts as a sensitizer of the Eu 3+ dopant red emission arising from intra-4f orbital transitions, and concurrently exhibits a strong blue photoluminescence originating from defect-based...
Article
Full-text available
Extensively studied Mn-doped semiconductor nanocrystals have invariably exhibited photoluminescence over a narrow energy window of width ≤150 meV in the orange-red region and a surprisingly large spectral width (≥180 meV), contrary to its presumed atomic-like origin. Carrying out emission measurements on individual single nanocrystals and supported...
Article
Full-text available
Understanding the influence of relevant parameters on the kinetics of nanocrystal formation, from reaction and nucleation to the final stages of growth in a homogeneous medium, is crucial in the design and synthesis of nanoparticles of desired dimension. ZnO is chosen as a model system to study spherical nanoparticle formation in solution, using a...
Article
Full-text available
The nature of the polarization-field in disorder induced nanoscale potential fluctuations (radiative traps) within (In,Ga)N based quantum-well (QW) heterostructures remains ambiguous. Spectrally resolved photoluminescence microscopy has been utilized to probe the local polarization field by monitoring the extent of quantum-confined Stark effect (QC...
Article
Full-text available
Spatially, spectrally, and temporally resolved photoluminescence (PL) microscopy was performed on InGaN quantum-well light emitting diodes to probe individual localized luminescent centers arising from disorder induced potential fluctuations. Two energetically distinct localization centers were identified where the photoemission quantum-efficiency...
Article
Full-text available
The high light-output efficiencies of InxGa1-xN quantum-well (QW)-based light-emitting diodes (LEDs) even in presence of a large number of nonradiative recombination centers (such as dislocations) has been explained by localization of carriers in radiative potential traps, the origins of which still remain unclear. To provide insights on the highly...
Article
Full-text available
The broad visible photoluminescence (PL) observed in ZnO nanocrystals (NCs) is widely attributed to multiple low lying surface-defects. We have performed steady state and time- resolved PL measurements on size-selected ZnO NCs in the strong confinement regimes. Our results show that radiative relaxation rates and coupling between excitons and surfa...
Article
Full-text available
The intrinsic spectral line widths of defect-related transitions in quantum-confined semiconductor nanocrystals are often difficult to estimate using ensemble measurements because the extent of inhomogeneous broadening due to particle size distributions is not known precisely. To address this problem, we performed spectrally resolved photoluminesce...

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