A5044021914- Organic Electronics and Photovoltaics
- Perovskite Materials and Applications
- Quantum Dots Synthesis And Properties
- Gas Sensing Nanomaterials and Sensors
- Nanowire Synthesis and Applications
- ZnO doping and properties
- Conducting polymers and applications
- Advanced Sensor and Energy Harvesting Materials
- Semiconductor materials and interfaces
- Transition Metal Oxide Nanomaterials
- Solid-state spectroscopy and crystallography
- Molecular Junctions and Nanostructures
- Advanced Photocatalysis Techniques
- Photonic Crystals and Applications
- Gold and Silver Nanoparticles Synthesis and Applications
- Semiconductor materials and devices
- 2D Materials and Applications
- Block Copolymer Self-Assembly
- Force Microscopy Techniques and Applications
- Ferroelectric and Piezoelectric Materials
- Thin-Film Transistor Technologies
- Advanced Memory and Neural Computing
- Copper-based nanomaterials and applications
- Fullerene Chemistry and Applications
- Marine Biology and Environmental Chemistry
Indian Institute of Technology Gandhinagar
2015-2024
University of Tübingen
2012-2016
Saha Institute of Nuclear Physics
1998-2015
University of North Texas
2006
The Ohio State University
2003
Indian Association for the Cultivation of Science
1981
Lead-free halide perovskites have gained immense popularity in photovoltaic and energy harvesting applications because of their excellent optical electrical attributes with minimal toxicity. We synthesized composite films lead-free Cs3Bi2Br9 perovskite embedded the polyvinylidene fluoride (PVDF) matrix investigated piezoelectric harvesting. Five PVDF@Cs3Bi2Br9 were fabricated varying wt% PVDF. The a 4 shows 85% activation electroactive β-phase Additionally, this exhibits maximum polarisation...
Two dimensional (2D) CsPb2Br5have been successfully synthesized via the chemical precipitation method. Detailed structural, morphological, optical, and dielectric studies of these materials have performed. These 2D CsPb2Br5plates (of thickness around 200-300 nm) are ascribed to a tetragonal lattice system withI4/mcmspace group. The attributes such as constant, electrical modulus, loss factor, DC, AC conductivities, observed be varying appreciably with temperature over an extensive frequency...
The main challenges impeding the widespread use of organic-inorganic lead halide perovskites in modern-day technological devices are their long-term instability and contamination. Among other environmentally convivial sustainable alternatives, Cs2SnX6 (X = Cl, Br, I) compounds have shown promise as ambient-stable, lead-free materials for energy harvesting, optoelectronic applications. Additionally, they demonstrated tremendous potential fabrication self-powered nanogenerators conjunction...
Sustainable energy harvesting is the need of hour, and piezoelectric nanogenerators (PENG) offer tremendous opportunities in this field. We have investigated mechanical applications a nanocomposite comprising low-dimensional halide perovskite (HP) polyvinylidene fluoride (PVDF). Cs4PbBr6 HP was prepared using mechanochemical synthesis, composite film PVDF with utilized as PENG to scavenge from day-to-day human biomechanical activities. The properties output results fabricated devices...
We investigate in situ the structural changes during self-assembly of PbS nanocrystals from colloidal solution into superlattices, solvent evaporation, and ligand exchange at acetonitrile/air interface by grazing incidence small-angle X-ray scattering (GISAXS). simulate fit diffraction peaks under distorted wave Born approximation (DWBA) to determine lattice parameters. observe a continuous isotropic contraction superlattice two different assembly steps, preserving body-centered cubic with...
This work explores resistive switching mechanisms in non-volatile organic memory devices based on tris(8-hydroxyquinolie)aluminum (Alq3). Advanced characterization tools are applied to investigate metal diffusion ITO/Alq3/Ag device stacks leading conductive filament formation. The morphology of Alq3/Ag layers as a function the evaporation conditions is studied by X-ray reflectivity, while depth profile analysis with photoelectron spectroscopy and time-of-flight secondary ion mass...
We present depth-resolved grazing incidence x-ray diffraction, small angle scattering and reflectivity studies on the structure of mixed C(60) diindinoperylene (DIP) films as a function mixing ratio. observe enhanced out-of-plane order smoothing compared to pure upon coevaporation DIP:C(60) thin (in different ratio) which otherwise phase separate. The ratio molecules can be tuned alter in-plane crystallite size well interisland distances molecules. Real-time in situ diffraction measurements...
We analyze the structure and morphology of mesocrystalline, body-centered tetragonal (bct) superlattices PbS nanocrystals functionalized with oleic acid. On basis combined scattering real space imaging, we derive a three-dimensional (3D) model superlattice show that bct benefits from balanced combination {100}PbS–{100}PbS {111}PbS–{111}PbS interactions between neighboring layers nanocrystals, which uniquely stabilizes this structure. These are enabled by coaxial alignment atomic lattices...
We synthesized 2D CsPb 2 Br 5 layered perovskite which shows piezoelectric and ferroelectric properties at room temperature. Additionally, composites of PVDF were fabricated to examine energy harvesting behavior as a nanogenerator.
We report on a series of ambient processed, all-inorganic, lead-free nanocrystalline perovskites, viz. Cs3Bi2Cl9–xBrx, which are halide-tunable and demonstrate photocatalytic CO2 reduction. The conversion yield to CO could be tuned by meticulously regulating the Cl-to-Br ratio within perovskite material. While all samples demonstrated reduction purely under photoillumination (i.e., illumination with an applied bias 0 V vs Ag/AgCl), it was remarkable that almost doubled for applying negative...
The synergistic influence of synthesized MoS2 (syn-MoS2) nanosheets and NaYF4:Yb,Tm,Nd upconversion nanoparticles (UCNP) on effective dye degradation is demonstrated. A detailed characterization bulk (b-MoS2), syn-MoS2 (with enhanced photocatalytic activity compared to the commercially available b-MoS2), UCNP was done. Optical properties revealed that emission spectra corresponding 450, 475, 650 nm overlap with absorption (∼455 635 nm). comparative methylene blue 96% could be achieved...
We report on a real-time in situ study of the growth α-sexithiophene silicon oxide substrates. Synchrotron-based X-ray diffraction experiments were performed during and directly after order to monitor process. observed coexistence two different crystal phases for substrate temperatures. For films prepared at 233 308 K disordered phase (β-phase) seems be dominant compared 373 where so-called low-temperature bulk (LT-phase) is dominant. From measurements we temperature film thickness dependent...
We report on a combined off-specular and specular x-ray scattering growth study of ultrathin films the prototypical organic semiconductor diindenoperylene (DIP, ${\mathrm{C}}_{32}{\mathrm{H}}_{16})$. investigate evolution in-plane correlation length kinetics including their dependence substrate temperature rate. observe temperature-dependent collective rearrangement DIP molecules from transient surface induced to thin-film phase, which can be rationalized by incorporating thickness-dependent...
We report the dielectric properties of a two-dimensional layered Ruddlesden-Popper halide perovskite ${\mathrm{Cs}}_{2}{\mathrm{PbI}}_{2}{\mathrm{Cl}}_{2}$ synthesized via simple mechanochemical process to explore fundamental aspects ionic conduction and relaxation mechanism over wide temperature frequency range. Several experimental techniques, such as complex impedance spectroscopy, alternating current (AC) conductivity electric modulus have been employed investigate nuances mechanisms,...
We investigate the structure of mixed thin films composed pentacene (PEN) and diindenoperylene (DIP) using X-ray reflectivity grazing incidence diffraction. For equimolar mixtures we observe vanishing in-plane order coexisting with an excellent out-of-plane order, a yet unreported disordering behavior in binary organic semiconductors, which are crystalline their pure form. One approach to rationalize our findings is introduce anisotropic interaction parameter framework mean field model. By...
Chiral halide perovskites are being extensively studied due to their promising spintronic and optoelectronic properties, where the organic chiral ligands introduce chirality into perovskites. Right-handed left-handed materials mirror images of one another break inversion symmetry, which produces ferroelectricity. In this work, we study dielectric, piezoelectric, ferroelectric properties (R)-(\ensuremath{-})-1-cyclohexylethylammonium)${\mathrm{Pb}\mathrm{I}}_{3}$...