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Dive into the research topics where Chandra Chowdhury is active.

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Featured researches published by Chandra Chowdhury.


Journal of Physical Chemistry Letters | 2016

Pseudo-Jahn-Teller Distortion in Two-Dimensional Phosphorus: Origin of Black and Blue Phases of Phosphorene and Band Gap Modulation by Molecular Charge Transfer.

Chandra Chowdhury; Sheik Jahiruddin; Ayan Datta

Phosphorene (Pn) is stabilized as a layered material like graphite, yet it possess a natural direct band gap (Eg = 2.0 eV). Interestingly, unlike graphene, Pn exhibits a much richer phase diagram which includes distorted forms like the stapler-clip (black Pn, α form) and chairlike (blue Pn, β form) structures. The existence of these phases is attributed to pseudo-Jahn-Teller (PJT) instability of planar hexagonal P6(6-) rings. In both cases, the condition for vibronic instability of the planar P6(6-) rings is satisfied. Doping with electron donors like tetrathiafulvalene and tetraamino-tetrathiafulvalene and electron acceptors like tetracyanoquinodimethane and tetracyanoethylene convert blue Pn into N-type and black Pn into efficient P-type semiconductors, respectively. Interestingly, pristine blue Pn, an indirect gap semiconductor, gets converted into a direct gap semiconductor on electron or hole doping. Because of comparatively smaller undulation in blue Pn (with respect to black Pn), the van der Waals interactions between the dopants and blue Pn is stronger. PJT distortions for two-dimensional phosphorus provides a unified understanding of structural features and chemical reactivity in its different phases.


Journal of Physical Chemistry Letters | 2017

Exotic Physics and Chemistry of Two-Dimensional Phosphorus: Phosphorene

Chandra Chowdhury; Ayan Datta

Phosphorene, the monolayer form of black phosphorus, is the most recent addition to graphene-like van der Waals two-dimensional (2D) systems. Due to its several interesting properties, namely its tunable direct band gap, high carrier mobility, and unique in-plane anisotropy, it has emerged as a promising candidate for electronic and optoelectronic devices. Phosphorene (Pn) reveals a much richer phase diagram than graphene, and it comprises the two forms namely the stapler-clip like (black Pn, α form) and chairlike (blue Pn, β form) structures. Regardless of its favorable properties, black Pn suffers from instability in oxygen and water, which limits its successful applications in electronic devices. In this Perspective, the cause of structural diversity of Pn, which leads to different properties of both black and blue Pn, is discussed. We provide possible solutions for protecting phosphorene from chemical degradation and its applications in the field of energy storage namely for Li and Na ion batteries.


Physical Chemistry Chemical Physics | 2016

Steric and electric field driven distortions in aromatic molecules: spontaneous and non-spontaneous symmetry breaking

Kalishankar Bhattacharyya; Ammu Surendran; Chandra Chowdhury; Ayan Datta

The structures of molecules form the cornerstone of our chemical knowledge. Lowering of symmetry in closed-shell molecules is often attributed to the Pseudo Jahn-Teller (PJT) distortions wherein non-adiabatic coupling (NAC) between the ground state and excited states creates vibrational instability along specific normal modes. Nevertheless, other factors like steric interactions are also well known in the literature to induce structural distortions. In this article, we consider two specific cases of molecular distortions - the first one being spontaneous for contorted polyaromatic hydrocarbons (c-PAH) where non-bonded repulsions between the two pairs of syn H-atoms in tribenzopyrene, TBP (1), can enforce either a C2v → C2 or C2v → Cs distortion. PJT-effects account for the correct preference of the Cs structure over C2 (by 4.6 kcal mol-1). The second case (non-spontaneous symmetry breaking) is that of benzene (2) and coronene (3) which upon application of sufficiently strong static external electric field develop vibrational instability along q(a2u) to cause D6h → C6v and D6h → C2 distortions for 2 and 3 respectively. An external electric field (FZ) was applied parallel to the aromatic ring of 2-3 for investigation of non-spontaneous symmetry breaking. Such electric field induced structural distortion is understood on the basis of excess charge accumulation of the planar rings which is circumvented by symmetry lowering. PJT effects seem to have significant consequences for identification of global minima amongst several local minimal molecular structures.


CrystEngComm | 2016

Multifunctional mixed ligand metal organic frameworks: X-ray structure, adsorption, luminescence and electrical conductivity with theoretical correlation

Biswajit Bhattacharya; Dilip K. Maity; Animesh Layek; Sk Jahiruddin; Arijit Halder; Arka Dey; Saheli Ghosh; Chandra Chowdhury; Ayan Datta; Partha Pratim Ray; Debajyoti Ghoshal

Two new mixed ligand metal–organic frameworks of Zn(II) with disodium 5-hydroxyisophthalate and 4,4′-azobispyridine (azbpy) ligands, {[Zn(azbpy)(HO-1,3-bdc)(H2O)]·(azbpy)}n (1) and {[Zn(azbpy)0.5(HO-1,3-bdc)(C2H5OH)]·(H2O)}n (2) have been synthesized by changing the reaction medium (methanol to ethanol) and structurally characterized by elemental analysis, IR, PXRD, TG and single crystal X-ray diffraction. Compound 1 exhibits a 2D sheet network structure with free azbpy ligands in its void space, and is stabilized by π–π and C–H⋯π interactions, whereas 2 has a 2D layered architecture with lattice water molecules in its void space. Compound 2 has a flexible structure and shows gated adsorption (gas and solvent) behavior, while framework 1 is nonporous. These two MOFs exhibit remarkable electrical conductivity values at room temperature and their comparison is discussed carefully. Theoretical calculations suggest that both the compounds are p-type semiconductors and correlate the structure–property relationship. Schottky barrier diode electronic devices have been fabricated by using these two semiconductor materials with aluminium (Al) and indium tin oxide (ITO) in sandwich configuration, ITO/MOF-1 or 2/Al, and both the devices exhibit sound rectification behavior. The photoluminescent properties of both the compounds in the solid state are also investigated in detail.


Journal of Molecular Graphics & Modelling | 2017

Density functional theory study of defective silicenes as anode materials for lithium ion batteries

Mohammad Jafar Momeni; Chandra Chowdhury; Morteza Mousavi-Khoshdel

In this contribution, we explore Li adsorption and diffusion on defective silicenes using first principles calculations. Defect formation energy (Ef) values showed that silicenes with 5105 and 5559 vacancy defects (Si-5559 and Si-5105) are likely to form during the fabrication process and Ef values are about one-third of graphenes. Calculation of Li adsorption energy indicated that Si-5559 and Si-5105 are better than pristine silicene for Li dispersion in the half-lithiated state. The diffusion barrier of Li on the surface of Si-5559 and Si-5105 and in the proximity of defected zone were obtained to be 0.24eV and 0.29eV, respectively. Diffusion barrier values show the easy motion of Li on these silicenes in comparison with defective graphenes. Ab-initio molecular dynamic (AIMD) simulations revealed that fully lithiated Si-5559 is not stable and can not accommodate lithium atoms. On the contrary, Si-5105 is stable and could store a certain amount of lithium atoms. The theoretical capacity of Si-5105 was calculated to be 664mAhg-1.


Journal of Physical Chemistry C | 2016

Two-Dimensional Group IV Monochalcogenides: Anode Materials for Li-Ion Batteries

Sharmistha Karmakar; Chandra Chowdhury; Ayan Datta


ACS energy letters | 2016

Capping Black Phosphorene by h-BN Enhances Performances in Anodes for Li and Na Ion Batteries

Chandra Chowdhury; Sharmistha Karmakar; Ayan Datta


Journal of Physical Chemistry C | 2017

Monolayer Group IV–VI Monochalcogenides: Low-Dimensional Materials for Photocatalytic Water Splitting

Chandra Chowdhury; Sharmistha Karmakar; Ayan Datta


Chemical Physics | 2015

Pseudo Jahn–Teller distortion for a tricyclic carbon sulfide (C6S8) and its suppression in S-oxygenated dithiine (C4H4(SO2)2)

Saied Md Pratik; Chandra Chowdhury; Rameswar Bhattacharjee; Sk Jahiruddin; Ayan Datta


Journal of Physical Chemistry C | 2018

Noble-Metal-Supported GeS Monolayer as Promising Single-Atom Catalyst for CO Oxidation

Sharmistha Karmakar; Chandra Chowdhury; Ayan Datta

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Ayan Datta

Indian Association for the Cultivation of Science

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Sharmistha Karmakar

Indian Association for the Cultivation of Science

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Sk Jahiruddin

Indian Association for the Cultivation of Science

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Ammu Surendran

Cochin University of Science and Technology

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Dilip K. Maity

Homi Bhabha National Institute

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