A5011161243- Photochemistry and Electron Transfer Studies
- Ionic liquids properties and applications
- Perovskite Materials and Applications
- Electrochemical Analysis and Applications
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Quantum Dots Synthesis And Properties
- Molecular Sensors and Ion Detection
- Spectroscopy and Quantum Chemical Studies
- Luminescence and Fluorescent Materials
- Porphyrin and Phthalocyanine Chemistry
- Crystallography and molecular interactions
- Solid-state spectroscopy and crystallography
- Analytical Chemistry and Sensors
- Surfactants and Colloidal Systems
- Chalcogenide Semiconductor Thin Films
- Optical properties and cooling technologies in crystalline materials
- Photochromic and Fluorescence Chemistry
- Radical Photochemical Reactions
- Metal complexes synthesis and properties
- Free Radicals and Antioxidants
- Molecular Junctions and Nanostructures
- DNA and Nucleic Acid Chemistry
- Organic Light-Emitting Diodes Research
- Protein Interaction Studies and Fluorescence Analysis
University of Hyderabad
2016-2025
University of Burdwan
2010
Bhabha Atomic Research Centre
2007-2010
Centre for Cellular and Molecular Biology
2010
The University of Tokyo
2006
University of Notre Dame
1988-2002
Indian Institute of Chemical Technology
2001
Indian Association for the Cultivation of Science
1983-1989
University of Lausanne
1987
Metal-halide perovskites have rapidly emerged as one of the most promising materials 21st century, with many exciting properties and great potential for a broad range applications, from photovoltaics to optoelectronics photocatalysis. The ease which metal-halide can be synthesized in form brightly luminescent colloidal nanocrystals, well their tunable intriguing optical electronic properties, has attracted researchers different disciplines science technology. In last few years, there been...
While perovskite nanocrystals (NCs) have shown great promise as materials for efficient light-emitting diodes (LEDs), low photoluminescence quantum yield (PLQY) of the blue-emitting perovskites is an impediment to development white LEDs which blue essential component. Herein, we report that room temperature postsynthetic treatment weakly blue-violet-emitting (PLQY 3%) CsPbCl3 NCs with CdCl2 results in instantaneous enhancement PLQY near-unity without affecting PL peak position (406 nm) and...
Room-temperature ionic liquids, particularly those based on substituted imidazolium cations, are currently being extensively studied for a variety of applications. Herein, we explore the suitability several salts in optical applications by carefully examining electronic absorption and fluorescence behavior these substances, generally believed to be transparent most UV region fully visible region. It is shown that all liquids characterized significant entire long tail extends into These...
Room temperature ionic liquids (RTILs) are viscous media consisting entirely of ions. Because the complex nature various interactions in these media, solvent properties RTILs very little understood. Since fluorescence response molecules comprising conjugated electron donor and acceptor groups, referred to as dipolar molecules, is one most frequently exploited sources information on whose largely unknown, it possible obtain insight into structure dynamics by studying behavior solutes media....
Defects have always been an integral part of semiconductor crystals, controlling their optical and electronic properties. Even though growing popularity the CsPbX3 (X = Cl, Br, I, mixture) nanocrystals (NCs) in various applications stems from defect-tolerant nature, properties, stability, practical utility these substances are still very much governed by defects. A variety methods, which halide-specific, developed to regulate activities defects for enhancing photoluminescence stability NCs....
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTBoosting the Photoluminescence of CsPbX3 (X = Cl, Br, I) Perovskite Nanocrystals Covering a Wide Wavelength Range by Postsynthetic Treatment with Tetrafluoroborate SaltsTasnim AhmedTasnim AhmedSchool Chemistry, University Hyderabad, Hyderabad 500046, IndiaMore Tasnim Ahmedhttp://orcid.org/0000-0002-5990-3891, Sudipta SethSudipta SethSchool Seth, and Anunay Samanta*Anunay SamantaSchool India*A.S. E-mail: [email protected]More...
Understanding the nature and dynamics of photo-induced transients all-inorganic perovskite nanocrystals (NCs) is key to their exploitation in potential applications. In order determine charge carriers, deactivation pathways dynamics, CsPbBr3, CsPbBr2I, CsPbBr1.5I1.5 CsPbI3 NCs are spectrally temporally characterized employing a combination femtosecond transient absorption (TA) photoluminescence (PL) up-conversion techniques global analysis data. The results provide distinct identities...
In Mn-doped CsPbCl<sub>3</sub>nanocrystals, Mn photoluminescence is widely tuned from yellow to red and exciton–dopant energy transfer timescales have been estimated through ultrafast transient absorption measurement.
The solvent strength and polarity of four imidazolium pyridinium based ionic liquids, as measured using two different fluorescent probes, indicate that these liquids are more polar than acetonitrile but less methanol.
Room-temperature ionic liquids are rapidly emerging as a new class of medium that is ideally suited for carrying out chemical reactions and various other applications. In this paper, steady-state time-resolved fluorescence behavior coumarin-153 (C153) have been reported in room-temperature liquid, 1-butyl-3-methylimidazolium tetrafluoroborate or [BMIM][BF4]. The polarity the solvent, estimated from maximum C153, found to be 48.9 on ET(30) scale. decay C153 [BMIM][BF4] dependent monitoring...
The role of hydrogen bonding in water is important determining the structure, stability, and function biological assemblies. supramolecular structure 1,4,7,10-tetraazacyclododecane, a molecule that has secondary NH bonds similar to those found systems, contains an infinite chain tetrameric clusters (depicted, oxygen: red; hydrogen: white). This motif, until now, not even been speculated upon.
The fluorescence behavior of several dipolar molecules has been studied in three room-temperature ionic liquids, namely, [BMIM][BF4], [EMIM][BF4], and [BMIM][PF6], as a function the excitation wavelength. Although large majority these systems show normal with no wavelength dependence, few surprisingly exhibit fairly strong excitation-wavelength-dependent media. shift maximum is measured to be between 10 35 nm. various parameters have carefully examined determine factors that contribute this...
Excited-state dipole moments of a set Coumarin dyes extensively used in laser applications have been determined for the first time, employing solvatochromic procedure utilising microscopic solvent polarity parameter, ENT. Our results are expected to be quite reliable view fact that correlation Stokes shifts is superior obtained using bulk functions. The experimentally dipole-moment changes fair agreement with recent semi-empirical computational predictions. It shown discrepancies observed...
Three-component systems, 1a−c and 2a,b, comprising 1,8-naphthalimide 4-methoxy-1,8-naphthalimide as fluorophore, a dimethylamino moiety guest binding site polymethylene group spacer, have been synthesized the fluorescence behavior of these systems has studied in absence presence salts several transition metal ions. The are found to be very weakly fluorescent compared their constituent fluorophores (3 4) this observation ascribed photoinduced intramolecular electron transfer (PIET) between...
Ionic liquids have generated tremendous excitement as a new class of solvent systems having the potential to serve an environmentally friendly alternative traditionally used volatile organic compounds and emerged specialty media or materials for many advanced processes devices. Solvent reorganization in ionic is complex process, which differs significantly from that conventional polar molecular solvents. This Perspective highlights present understanding mechanism time scale dynamics...
Room temperature ionic liquids have emerged as nature-friendly media suitable for various applications. In this work, steady-state and time-resolved fluorescence behavior of coumarin 153 (C153) 6-propionyl-2-dimethylaminonaphthalene (PRODAN) been reported in two room-temperature based on substituted imidazolium salts. The the probe molecules suggests that these are more polar than acetonitrile. polarity is found to be comparable 2-propanol. No significant difference could observed although...
Photophysical behavior of two series 4-amino-1,8-naphthalimide derivatives differing in the amino functionality has been studied as a function polarity medium. The location lowest singlet state systems, intramolecular charge transfer (ICT) nature, is largely controlled by conformation 4-amino group rather than its electron-donating ability. fluorescence properties systems are strongly dependent on nature well media. An increase length dialkyl groups connected to nitrogen or an size ring...
Study of the emission behavior all-inorganic perovskite nanocrystals CsPbBr3 and CsPbBr2I as a function excitation power employing fluorescence correlation spectroscopy conventional techniques reveals blinking in microsecond time scale photoinduced enhancement. The observation provides insight into radiative nonradiative deactivation pathways these promising substances. Because both photoactivation processes are intimately linked to charge separation efficiency dynamics nanocrystals, key...
Abstract A facile and highly reproducible room temperature, open atmosphere synthesis of cesium lead halide perovskite nanocrystals six different morphologies is reported just by varying the solvent, ligand reaction time. Sequential evolution quantum dots, nanoplates nanobars in one medium nanocubes, nanorods nanowires another demonstrated. These nanoparticles are shown to be excellent crystalline quality with high fluorescence yield. mechanism formation shapes sizes proposed. Considering...
Interaction of bovine serum albumin (BSA) with two series dipolar molecules having both rigid and flexible structures has been studied by monitoring the spectral temporal behavior intramolecular charge transfer fluorescence systems. The binding sites molecular systems in BSA have located help docking studies. Three different varying hydrophobicity identified where these are located. Binding hydrophobic domains leads to a blue shift spectra an enhancement intensity lifetime. This is found be...
Quantum-confined perovskites are a new class of promising materials in optoelectronic applications. In this context, zero-dimensional perovskite-related substance, Cs4PbBr6, having high exciton binding energy can be an important candidate, but its photoluminescence (PL) is topic recent debate. Herein, we report ambient condition controlled synthesis Cs4PbBr6 microdisks different shapes and dimensions which exhibit fairly strong green PL (quantum yield up to 38%, band gap ∼2.43 eV) the solid...
The lack of long-term stability, the presence toxic lead, and a low photoluminescence (PL) efficiency are major obstacles to commercialization lead-halide perovskite-based optoelectronic photovoltaic devices. Herein we report facile ambient condition doping protocol that addresses all three issues CsPbX3 perovskite nanocrystals (NCs) substantial extent. We show room-temperature treatment these NCs with MgX2 results in partial (18–23%) replacement enhances PL quantum yield green-emitting...
Zero-dimensional (0-D) perovskites and perovskite-related materials are an emerging class of optoelectronic exhibiting strong excitonic properties and, quite often, high photoluminescence (PL) in the solid state. Here we highlight two different classes 0-D with contrasting structural optical properties, focusing mainly on less explored but rapidly growing bulk quantum termed as (0-D PRMs), whose PL intriguing a topic recent debate. We attempt to present here comprehensive picture rationalize...
Stable green-emitting perovskite nanocrystals (NCs) with general formula APbBr3, exhibiting a high photoluminescence quantum yield (PLQY), narrow bandwidth, and adjustable PL in the 510–535 nm region are coveted materials for optoelectronic applications. A generic method of obtaining both hybrid all-inorganic NCs desired characteristics is, however, lacking. Herein, we report methodology synthesis CsPbBr3, FAPbBr3, MAPbBr3 employing N-bromosuccinimide as bromide precursor. The show uniform...