Au, Ag and bimetallic Au/Ag nanoclusters were prepared under similar microwave-irradiated synthesis conditions in aqueous solutions, using BSA as a stabilizer. The nanoclusters exhibited strong fluorescence with characteristic emission spectral peak features that suggested the presence of multiple emissive states in each case. Time-resolved emission studies revealed the very rare incidence of the time-dependent emission Stokes shift in metal nanoclusters over a time-scale of ∼10 ns. The shifts were of varying degrees: ∼200 cm-1 for Ag, ∼750 cm-1 for Au and ∼1400 cm-1 for Au/Ag nanoclusters. Application of the Time-Resolved Area Normalized Emission Spectra (TRANES) method confirmed the existence of multiple emissive species in each of the nanoclusters, which also helped to explain the time-dependent emission Stokes shift. © 2019 The Royal Society of Chemistry and Owner Societies.

DEBABRATA MANDAL

Chemistry

N BASU

University of Calcutta (informally known as Calcutta University or CU) is a collegiate public state university located in Kolkata, West Bengal, India.&nbsp;Within India it is recognized as a &quot;Five-Star University&quot; and accredited &quot;A&quot; Grade by National Assessment and Accreditation Council.

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The University of Calcutta has secured the Fifth position among the Universities of India in the prestigious &quot;Indian University Ranking 2019&quot; list, released by the NIRF of the Ministry of Human Resource Development, Government of India.

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It was established on 24 January 1857, and was one of the first institutions in Asia to be established as a multidisciplinary and Western-style university. Its alumni and faculty include several heads of state, heads of government, social reformers, prominent artists, only academy award winner and Dirac medal winner in India, many Fellows of the Royal Society and five Nobel laureates as of 2019 which is highest in South Asia.

University Of Calcutta

Photochemical and Photobiological Sciences

Photophysical studies on the 4'-N,N-dimethylamino-3-hydroxyflavone fluorophore were performed in hydrogen-bonding solvents. Both in hydrogen-bonding acids and bases, clear evidence of excited state intramolecular proton transfer (ESIPT) emerged from steady-state and time-resolved spectroscopies. The same was also observed for the fluorophores residing in the hydrophilic shell region of aqueous micelles, where they come into close contact with water molecules at the micelle-water interface. Slow ∼ 100 ps ESIPT time-constants were determined in these systems that correlated well with solvation dynamics. The slow ESIPT time-constants are attributed to activated barrier crossing from the solvent-relaxed enol form to tautomer form in the excited state energy surface of the flavone. In contrast to the barrier-less ESIPT occurring in early (<1 ps) time-scales, this activated proton-transfer event necessarily requires extensive reorganization of flavone···solvent intermolecular hydrogen bonds, a process heavily modulated by the relatively slower dynamics of solvent relaxation around the excited fluorophore. © 2015 American Chemical Society.

Journal of Physical Chemistry B

Proton Transfer Dynamics of 4'- N, N -Dimethylamino-3-hydroxyflavone Observed in hydrogen-bonding solvents and aqueous micelles

Stable, fluorescent Ag nanoclusters were prepared in aqueous solutions of Na+ salt of the carboxylate-rich polymer poly(acrylic acid-co-maleic acid) under brief spells of UV irradiation. The nanoclusters were nearly spherical, with diameters within 1.90 ± 0.50 nm, but displayed a prominent red edge excitation shift (REES) of fluorescence upon exciting within the visible absorption band, indicating heterogeneity of energy level distributions. Spectroscopic studies revealed that irrespective of whether the nanoclusters are excited in their UV or visible absorption bands, their fluorescence always ensues from the same manifold of emissive states, with a broad range of fluorescence lifetimes from ∼150 fs to 1 ns. © the Owner Societies 2016.

Physical Chemistry Chemical Physics

Fluorescent Ag nanoclusters prepared in aqueous poly(acrylic acid-co-maleic acid) solutions: A spectroscopic study of their excited state dynamics, size and local environment

Analytical Chemistry

Facile Synthesis of Enhanced Fluorescent Gold–Silver Bimetallic Nanocluster and Its Application for Highly Sensitive Detection of Inorganic Pyrophosphatase Activity

The Journal of Physical Chemistry C

Ultrafast Relaxation Dynamics of Luminescent Rod-Shaped, Silver-Doped AgxAu25–x Clusters

Density Functional Theory Studies on Structure, Ligand Exchange, and Optical Properties of Ligand-Protected Gold Nanoclusters: Thiolate versus Selenolate

Journal	Data powered by TypesetPhotochemical and Photobiological Sciences
Publisher	Data powered by TypesetRoyal Society of Chemistry
ISSN	1474-905X