A5103084825- Perovskite Materials and Applications
- Solid-state spectroscopy and crystallography
- Electronic and Structural Properties of Oxides
- Quantum Dots Synthesis And Properties
- Nuclear Materials and Properties
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Radioactive element chemistry and processing
- Nuclear reactor physics and engineering
- Optical properties and cooling technologies in crystalline materials
- Ferroelectric and Piezoelectric Materials
- Advanced Photocatalysis Techniques
- Electrocatalysts for Energy Conversion
- Microstructure and mechanical properties
- Photorefractive and Nonlinear Optics
- Multiferroics and related materials
- Magnetic and transport properties of perovskites and related materials
- Copper Interconnects and Reliability
- Advancements in Solid Oxide Fuel Cells
- Chalcogenide Semiconductor Thin Films
- Catalytic Processes in Materials Science
- Semiconductor materials and devices
- nanoparticles nucleation surface interactions
- Acoustic Wave Resonator Technologies
- Solidification and crystal growth phenomena
Indian Association for the Cultivation of Science
2018-2023
Indian Institute of Technology Gandhinagar
2021-2023
Centurion University of Technology and Management
2022
Georgia Institute of Technology
2012-2017
University of Florida
2008-2014
Los Alamos National Laboratory
2011
Pennsylvania State University
2009
Louisiana State University
2005
Louisiana State University Agricultural Center
2004
In a generic synthesis approach, all three CsPbX3 (X=Cl, Br and I) perovskite nanocrystals having near unity quantum yields is reported. This has been achieved by injecting the desired amount of preformed alkylammonium halide salts which acted as dual source providing ions capping agent to an equimolar non-halide Pb Cs precursors in reaction flask at optimized temperature. The composition sensitivity ratio, high temperature reaction, injection ammonium remained key parameters for obtaining...
Ferroelectric $180\ifmmode^\circ\else\textdegree\fi{}$ domain walls are well-known to be predominantly Ising-like. Using density functional theory, and molecular dynamics simulations, the in prototypical ferroelectrics lead titanate $({\text{PbTiO}}_{3})$ lithium niobate $({\text{LiNbO}}_{3})$ shown have mixed character; while Ising-like, they also manifest some Bloch- N\'eel-like character. Phase-field calculations show that such wall character can dramatically enhanced nanoscale thin film...
Bright lead halide perovskite nanocrystals, which have been extensively studied in the past 5 years, are mostly confined to a six faceted hexahedron (cube/platelet) shape. With variations of ligand, precursor, reaction temperature, and surface modification, their brightness has enhanced phase became stable, but ultimate nanocrystals still retained cube or platelet shape most hot injection reactions. In contrast, by exploration α-halo ketone amine as different shaped without compromising...
High-energy-emitting CsPbCl3 nanocrystals have shown significant loss and enhancement of their emission intensity (∼40–50 folds) during purification surface treatments, respectively. This confirms that the surfaces these are very sensitive. In this Letter, physical insights interface bindings on blue-emitting with different passivating agents consequential impact investigated. Using various metal chlorides irrespective charge size ions, acetates, nonmetal chloride, predominant influence...
Annealing perovskite nanocrystals at high reaction temperature changes their crystal phase, shape, and optical properties. Carrying out reactions between 180 250 °C, the impact of thermal annealing for CsPbCl3 CsPbBr3 in a flask was investigated here. At higher temperature, phase change observed instantly, which could not be trapped even with ice-bath cooling. Interestingly, using calculated amount preformed alkylammonium halides as dual passivating agents, both stabilized hours °C. CsPbCl3,...
Pretreatment using metal chlorides during the formation of halide deficient free perovskite nanocrystals is reported. Among several chlorides, Cu(II)Cl2 was observed to be ideal for synthesis highly emitting CsPbCl3 at high reaction temperature. Because temperature remained more favorable dopant insertion, doping Mn(II) carried out under this halide-rich system, and nearly 68% photoluminescence quantum yield recorded. Analysis could not provide strong evidence insertion Cu(II) inside...
Abstract In a generic synthesis approach, all three CsPbX 3 (X=Cl, Br and I) perovskite nanocrystals having near unity quantum yields is reported. This has been achieved by injecting the desired amount of preformed alkylammonium halide salts which acted as dual source providing ions capping agent to an equimolar non‐halide Pb Cs precursors in reaction flask at optimized temperature. The composition sensitivity ratio, high temperature reaction, injection ammonium remained key parameters for...
A minute difference in solvent polarity of hydrophobic solvents can drastically alter the rate formation cesium lead halide perovskite nanocrystals. This has been observed at room temperature and single-solvent synthesis routes for bromide chloride Through exploration Pb-thiolate as active precursor using seven different solvents, which varied from chloroform to hexane, phase changed orthorhombic-CsPbBr3 trigonal-Cs4PbBr6. In contrast, chloride, remained cubic-CsPbCl3 all but their shape...
Doping Mn(II) in inorganic Ruddlesden-Popper phase Cs2PbCl2I2 perovskite nanoplatelets is reported. The host nanostructures were prepared with a calculative protocol taking the exact required composition of Cs(I) and Pb(II) injecting preformed mixed oleylammonium chlorides iodides at optimized reaction temperature. Reactions various halides their mixtures, but stable Cs2PbX4 system was obtained only for chloride-iodide mixed-halide system. Introduction along Pb(II), resulted successful...
Designing heterostructures of soft ionic nanocrystals with metallic or covalent nanostructures having epitaxial junctions in solution poses several fundamental challenges. Hence, spite large successes developing lead halide perovskite nanocrystals, the chemistry formation their facet-directive growth noble metals cannot be explored yet. To address this, herein, orthorhombic CsPbBr3 and cubic Pt multiple directional approaches are reported. Appropriate facets high-temperature reaction key...
Density functional theory at the level of local density approximation with projector augmented wave method is used to determine structure 180° domain walls in tetragonal ferroelectric PbTiO(3). In agreement previous studies, it found that PbO-centered {100} have lower energies than TiO(2)-centered walls, leading a Peierls potential barrier for wall motion along <010> ∼36 mJ m(-2). addition Ising-like polarization axis, near wall, there small wall-normal direction away from wall. These...
Facet engineering in nanocrystals is typically controlled by the surface atoms of crystal and interaction interface binding ligands. This has been extensively studied for covalent chalcogenide nanocrystals, but little progress made ionic halide perovskite nanocrystals. Stabilizing different facets, mostly, determines nature polyhedral shapes also helps understanding formation their anisotropic structures. Recent progresses suggest that formations are mostly reagent specific. Two reagents,...
<div class="section abstract"><div class="htmlview paragraph">A novel sintering method of bridging the two mechanically polished and oriented single-crystals together face-to-face in a non- environmental controlled atmosphere to fabricate bicrystal substrate NaCl macroscopic thickness, with common zone axis having planarity over large areas, has been developed. Epitaxial [001] bicrystalline thin face-centered cubic (fcc) metal film surface-reactive metal-containing tilt grain...
Thorium dioxide (ThO(2)) is of great interest to energy research as thorium-based nuclear fuel offers the promise increased proliferation resistance, longer cycles, higher burn-up and improved wasteform characteristics in generation power. However, understanding ThO(2) a not comprehensive UO(2). In order improve atomic level fuels, we have developed eight interatomic potential descriptions by fitting experimental lattice parameter, elastic constants static dielectric constants. Using these...
The phase diagram of ${\mathrm{LaFeO}}_{3}$ (010) surfaces is developed by ab initio thermodynamics. stabilities LaO- and ${\mathrm{FeO}}_{2}$-terminated are investigated at temperatures representative solid oxide fuel cell (SOFC) operating conditions [773, 1073, 1223 K $p$(O${}_{2}$) \ensuremath{\approx} 0.21 atm]. For LaO-type surfaces, it predicted that the most stable surface structure oxidized all considered. ${\mathrm{FeO}}_{2}$-type to change from (at 773 K) stoichiometric 1073 K)....
This work proposes an empirical, variable charge potential for Ti and TiO2 systems based on the charge-optimized many-body (COMB) framework. The parameters of function are fit to structural mechanical properties hcp phase, rutile energetics polymorphs both TiO2. relative stabilities surfaces predicted compared results density functional theory (DFT) empirical calculations. transferability developed is demonstrated by determining adsorption energy Cu clusters various sizes TiO2(1 1 0) surface...
The increase of the stability perovskite nanocrystals with respect to exposure polar media, layers growth, or shelling different materials is in demand. While these are widely studied for metal chalcogenide nanocrystals, it has yet be explored nanocrystals. Even growth a single monolayer on any facet entire surface could not established yet. To address this, herein, secondary approach leading creation lattice subsequent expansion preformed CsPbBr3 reported. As direct layer by adding...
Halide perovskite nanocrystals are the subject of in-depth research because their bright color-tunable optical emissions. Synthesis these and phase stability in different halide compositions reaction environments also extensively studied. However, going beyond nanocrystals, chemistry epitaxial growth metallic crystals on selective facets ionic has not been largely established yet. For formation heteronucleations as well retaining relation at junction, a high temperature remains key factor....