Indian Association for The Cultivation of Science
Kolkata, India

Indian Association for the Cultivation of Science is an institute of higher learning in Kolkata, India. Established in 1876 by Mahendra Lal Sircar, a private medical practitioner, it focuses on fundamental research in basic science. It is India's oldest research institute.Located at Jadavpur, South Kolkata beside Jadavpur University, Central Glass and Ceramic Research Institute and Indian Institute of Chemical Biology it is spread over a limited area of 9.5 acres. Wikipedia.

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Kundu S.,Indian Association for The Cultivation of Science | Patra A.,Indian Association for The Cultivation of Science
Chemical Reviews | Year: 2017

Recent advances and the current status of challenging light-harvesting nanomaterials, such as semiconducting quantum dots (QDs), metal nanoparticles, semiconductor-metal heterostructures, π-conjugated semiconductor nanoparticles, organic-inorganic heterostructures, and porphyrin-based nanostructures, have been highlighted in this review. The significance of size-, shape-, and composition-dependent exciton decay dynamics and photoinduced energy transfer of QDs is addressed. A fundamental knowledge of these photophysical processes is crucial for the development of efficient light-harvesting systems, like photocatalytic and photovoltaic ones. Again, we have pointed out the impact of the metal-nanoparticle-based surface energy transfer process for developing light-harvesting systems. On the other hand, metal-semiconductor hybrid nanostructures are found to be very promising for photonic applications due to their exciton-plasmon interactions. Potential light-harvesting systems based on dye-doped π-conjugated semiconductor polymer nanoparticles and self-assembled structures of π-conjugated polymer are highlighted. We also discuss the significance of porphyrin-based nanostructures for potential light-harvesting systems. Finally, the future perspective of this research field is given. © 2016 American Chemical Society.

Das A.,Indian Association for The Cultivation of Science | Ghosh S.,Indian Association for The Cultivation of Science
Angewandte Chemie - International Edition | Year: 2014

We have collated various supramolecular designs that utilize organic donor-acceptor CT complexation to generate noncovalently co-assembled structures including fibrillar gels, micelles, vesicles, nanotubes, foldamers, conformationally restricted macromolecules, and liquid crystalline phases. Possibly inspired by nature, chemists have extensively used hydrogen bonding as a tool for supramolecular assemblies of a diverse range of abiotic building blocks. As a structural motif, CT complexes can be compared to hydrogen-bonded complexes in its directional nature and complementarities. Additional advantages of CT interactions include wider solvent tolerance and easy spectroscopic probing. Nevertheless the major limitation is their low association constant. This article shows different strategies have evolved over the years to overcome this drawback by reinforcing the CT interactions with auxiliary noncovalent forces without hampering the alternate stacking mode. Emerging reports on promising CT complexes in organic electronics are intimately related to various supramolecular designs that one can postulate based on donor-acceptor CT interactions. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Dutta S.,National Taiwan University | Bhaumik A.,Indian Association for The Cultivation of Science | Wu K.C.-W.,National Taiwan University
Energy and Environmental Science | Year: 2014

Hierarchically porous carbons (HPCs) with 1D to 3D network are attracting vast interest due to their potential technological application profile ranging from electrochemical capacitors, lithium ion batteries, solar cells, hydrogen storage systems, photonic material, fuel cells, sorbent for toxic gas separation and so on. Natural raw-materials such as biomass-biopolymer derived hierarchical nanostructured carbons are especially attractive for their uniform pore dimensions which can be adjustable over a wide range of length scales. Good electrical conductivity, high surface area, and excellent chemical stability are unique physicochemical properties which are responsible for micro/nanostructured porous carbon to be highly trusted candidate for emerging nanotechnologies. This review focuses on the 'out-of-the-box' synthetic techniques capable of deriving HPC with superior application profiles. The article presents the promising scope of accessing HPCs from (1) hard-templating, soft-templating, and non-templating routes, (2) biopolymers with a major focus on non-templating strategies. Subsequently, emerging strategies of hetero-atom doping in porous carbon nanostructures are discussed. The review will highlight the contribution of synergistic effect of macro-meso-micropores on a range of emerging applications such as CO2 capture, carbon photonic crystal sensors, Li-S batteries, and supercapacitor. Mechanism of ion transport and buffering, electrical double layer enhancement have been discussed in the context of pore structure and shapes. We will also show the differences of HPC and ordered mesoporous carbon (OMC) in terms of their synthesis strategies and choices of template for self-assembly. How the remarkable mechanical strength of the HPCs can be achieved by selecting self-assembling template, whereas collapse of mesostructure via decomposition of framework occurs due to poor thermal stability or high N-content of the carbon source will be discussed. © 2014 the Partner Organisations.

Jose D.,Indian Association for The Cultivation of Science | Datta A.,Indian Association for The Cultivation of Science
Accounts of Chemical Research | Year: 2014

The discovery of graphene and its remarkable and exotic properties have aroused interest in other elements and molecules that form 2D atomic layers, such as metal chalcogenides, transition metal oxides, boron nitride, silicon, and germanium. Silicene and germanene, the Si and Ge counterparts of graphene, have interesting fundamental physical properties with potential applications in technology. For example, researchers expect that silicene will be relatively easy to incorporate within existing silicon-based electronics.In this Account, we summarize the challenges and progress in the field of silicene research. Theoretical calculations have predicted that silicene possesses graphene-like properties such as massless Dirac fermions that carry charge and the quantum spin Hall effect. Researchers are actively exploring the physical and chemical properties of silicene and tailoring it for wide variety of applications.The symmetric buckling in each of the six-membered rings of silicene differentiates it from graphene and imparts a variety of interesting properties with potential technological applications. The pseudo-Jahn-Teller (PJT) distortion breaks the symmetry and leads to the buckling in silicenes. In graphene, the two sublattice structures are equivalent, which does not allow for the opening of the band gap by an external electric field. However, in silicene where the neighboring Si atoms are displaced alternatively perpendicular to the plane, the intrinsic buckling permits a band gap opening in silicene in the presence of external electric field. Silicene's stronger spin orbit coupling than graphene has far reaching applications in spintronic devices. Because silicon prefers sp 3 hybridization over sp2, hydrogenation is much easier in silicene. The hydrogenation of silicene to form silicane opens the band gap and increases the puckering angle. Lithiation can suppress the pseudo-Jahn-Teller distortion in silicene and hence can flatten silicene's structure while opening the band gap.So far, chemists have not successfully synthesized and characterized a free-standing silicene. But recently chemists have successfully produced silicene sheets and nanoribbons over various substrates such as silver, diboride thin films, and iridium. The supporting substrate critically controls the electronic properties of silicene, and the match of the appropriate support and its use is critical in applications of silicene. © 2013 American Chemical Society.

Polkovnikov A.,Boston University | Sengupta K.,Indian Association for The Cultivation of Science | Silva A.,Abdus Salam International Center For Theoretical Physics | Vengalattore M.,Cornell University
Reviews of Modern Physics | Year: 2011

This Colloquium gives an overview of recent theoretical and experimental progress in the area of nonequilibrium dynamics of isolated quantum systems. There is particularly a focus on quantum quenches: the temporal evolution following a sudden or slow change of the coupling constants of the system Hamiltonian. Several aspects of the slow dynamics in driven systems are discussed and the universality of such dynamics in gapless systems with specific focus on dynamics near continuous quantum phase transitions is emphasized. Recent progress on understanding thermalization in closed systems through the eigenstate thermalization hypothesis is also reviewed and relaxation in integrable systems is discussed. Finally key experiments probing quantum dynamics in cold atom systems are overviewed and put into the context of our current theoretical understanding. © 2011 American Physical Society.

Adarsh N.N.,Indian Association for The Cultivation of Science | Dastidar P.,Indian Association for The Cultivation of Science
Chemical Society Reviews | Year: 2012

The last two decades have witnessed the research activities in the area of coordination polymers (CPs), which are structurally diverse and functionally intriguing materials. In this endeavor, the most exploited ligand has been a structurally rigid N-donor compound having an innocent backbone (incapable of forming hydrogen bond) namely 4,4′-bipyridine. Much has been achieved by exploiting this wonder ligand in the area of CPs. However, the positional isomers such as 3,3′-bipyridine or 4,3′-bipyridine (which understandably induce diverse ligating topology as compared to their more symmetrical 4,4′ counterpart) were not exploited in much detail presumably because of the difficulty in their synthetic accessibility. To get access to such N-donor ditopic ligands having diverse ligating topology, much efforts have been focused in the last decade or so to design such positional isomers of 4,4′-bipyridine having a non-innocent backbone (capable of forming hydrogen bond). The principal focus of such studies is to decipher the effect of diverse ligating topology and the non-innocent backbone of the ligands on the overall supramolecular structures and functions of the resultant CPs. This tutorial review aims at highlighting some of the developments of such structurally diverse and functionally intriguing CPs derived from N-donor ditopic ligands having a non-innocent backbone. © 2012 The Royal Society of Chemistry.

Dan K.,Indian Association for The Cultivation of Science | Ghosh S.,Indian Association for The Cultivation of Science
Angewandte Chemie - International Edition | Year: 2013

An amphiphilic triblock copolymer segmented by an acid-labile β-thiopropionate linker was synthesized from a dithiol, a diacrylate, and an acrylate-terminated hydrophilic polymer in two steps in one pot. It showed spontaneous vesicular assembly, and the stimuli-responsive disassembly at mild acidic pH values resulted in sustained release of noncovalently encapsulated guest molecules. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Samanta D.,Indian Association for The Cultivation of Science | Sarkar A.,Indian Association for The Cultivation of Science
Chemical Society Reviews | Year: 2011

Attachment of biomolecules on gold, silicon or glass surfaces has direct implications for the development of novel biosensors in the context of nanoscale detection of pathogens and other metabolites related to issues of human health. In this critical review, we have highlighted the current developments in various techniques of immobilization of biomolecules, specifically biological macromolecules on surfaces through the modification of a functional self-assembled monolayer. The utility of such immobilized biomolecules in the area of biosensing in nanoscale has been surveyed. Merits and demerits of some of the methods with reference to sensitivity of detection and practical use have been discussed (221 references). © 2011 The Royal Society of Chemistry.

Ravikumar I.,Indian Association for The Cultivation of Science | Ravikumar I.,University of Texas at Austin | Ghosh P.,Indian Association for The Cultivation of Science
Chemical Society Reviews | Year: 2012

This tutorial review focuses on some recent aspects in the development of synthetic receptors for selective sulfate anion recognition and separation, with a special emphasis to: (i) receptors for selective recognition of sulfate in organic and aqueous media and (ii) receptors for separation of sulfate from water via liquid-liquid extraction and crystallization. © 2012 The Royal Society of Chemistry.

Das A.,Indian Association for The Cultivation of Science | Ghosh S.,Indian Association for The Cultivation of Science
Angewandte Chemie - International Edition | Year: 2014

A naphthalene diimide (NDI) building block containing hydrazide (H1) and hydroxy (H2) groups self-assembled into a reverse-vesicular structure in methylcyclohexane by orthogonal H-bonding and π-stacking. At an elevated temperature (LCST=43°C), destruction of the assembled structure owing to selective dissociation of H2-H2 H bonding led to macroscopic precipitation. Further heating resulted in homogeneous redispersion of the sample at 70°C (UCST) and the formation of a reverse-micellar structure. In the presence of a pyridine (H3)-functionalized pyrene (PY) donor, a supramolecular dyad (NDI-PY) was formed by H2-H3 H-bonding. Slow transformation into an alternate NDI-PY stack occurred by a folding process due to the charge-transfer interaction between NDI and PY. The mixed NDI-PY assembly exhibited a morphology transition from a reverse micelle (with a NDI-PY mixed-stack core) below the LCST to another reverse micelle (with a NDI core) above the UCST via a "denatured" intermediate. So many opportunities to get together: A naphthalene diimide building block 1 underwent self-assembly by orthogonal hydrogen bonding in a nonpolar solvent to form reverse vesicles, the temperature-dependent denaturation and redissolution of which led to reverse micelles. The coassembly of 1 with a pyrene donor 2 gave a transient donor-acceptor (D-A) complex, which formed an alternate D-A stack through a charge-transfer interaction (see picture). Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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