A5045951749- Perovskite Materials and Applications
- Material Dynamics and Properties
- Chalcogenide Semiconductor Thin Films
- Quantum Dots Synthesis And Properties
- Solid-state spectroscopy and crystallography
- Conducting polymers and applications
- Spectroscopy and Quantum Chemical Studies
- Thermodynamic properties of mixtures
- TiO2 Photocatalysis and Solar Cells
- Organic Electronics and Photovoltaics
- Advanced Fiber Laser Technologies
- Advanced Photocatalysis Techniques
- solar cell performance optimization
- Advanced Photonic Communication Systems
- Advancements in Solid Oxide Fuel Cells
- Thermodynamic and Structural Properties of Metals and Alloys
- Liquid Crystal Research Advancements
- Semiconductor Quantum Structures and Devices
- Photonic Crystal and Fiber Optics
- Theoretical and Computational Physics
- Metallurgical and Alloy Processes
- Electrokinetic Soil Remediation Techniques
- Organic Light-Emitting Diodes Research
- Radio Frequency Integrated Circuit Design
- Chemical Thermodynamics and Molecular Structure
University of Luxembourg
2013-2024
Tilka Manjhi Bhagalpur University
2022-2024
Aeronautical Development Agency
2022
Indian Institute of Science Bangalore
2018-2022
Technical University of Munich
1997-2021
Indian Institute of Technology Delhi
2016-2017
Tuning the energy levels of halide perovskite by controlling deposition dipolar self-assembled monolayers.
Within the mode-coupling theory (MCT) for dynamics of simple liquids, leading corrections to asymptotic solutions relaxation in vicinity an ideal glass transition are derived. The formulas used determine range validity scaling-law description MCT results \ensuremath{\alpha} and \ensuremath{\mathrm{B}} processes glass-forming systems. Solutions equations motion calculated a hard-sphere colloidal suspension model compared with derived analytical results. leading-order shown describe major...
First-principles simulations reveal the competition of defect formation and healing at grain boundaries in lead-halide perovskites. Fast halide migration GBs mediates structural healing, but also gives rise to enhanced Frenkel formation.
The mode-coupling theory for ideal liquid-glass transitions is extended so that the structural relaxation reorientational degrees of freedom a linear molecule, which immersed in system spherical particles, can be described. Closed equations motion correlation functions formed with tensor density fluctuations are derived, deal molecule's translational and motion. From these nonergodicity parameters hard dumbbell molecule calculated, quantify its arrest hard-sphere glass. For top-down...
The structural relaxation spectra and the crossover from to oscillation dynamics, as measured by Wuttke et al. [Phys. Rev. Lett. 72, 3052 (1994)] for glycerol within GHz band depolarized light scattering, are described solutions of a schematic mode coupling theory model. applicability scaling laws discussion model is considered.
Absolute photoluminescence measurements present a tool to predict the quality of photovoltaic absorber materials before finishing solar cells. Quasi Fermi level splitting predicts maximal open circuit voltage. However, various methods extract quasi are plagued by systematic errors in range 10-20 meV. It is important differentiate between radiative loss and shift emission maximum. They not same when using maximum as "radiative" band gap from efficiency, 10 40 meV too low for typical...
Metal halide perovskites have the potential to revolutionize field of photovoltaics, though limited stability has impeded commercial exploitation. The soft heterointerface between perovskite and charge-transporting layer is one major bottlenecks that limits operational stability. Here, we present rationally designed molecular modulators synergistically improve α-FAPbI3-based solar cells while retaining power conversion efficiency (PCE) 24.0% with a high open-circuit voltage (VOC) ∼1.195 V....
Carotenoids are natural pigments responsible for coloring in flowers and seeds. The semiconducting nature of carotenoids makes them a suitable candidate solar harvesting biodegradable nanoelectronic devices.
Light-induced degradation in metal halide perovskites is a major concern that can potentially hamper the commercialization of perovskite optoelectronic devices.
Identifying sources of nonradiative recombination and quantifying charge carrier extraction in halide perovskite solar cells are important further developing this thin-film technology. Steady-state time-resolved photoluminescence (TRPL), combination with analytical modeling, have emerged as non-destructive tools to achieve the desired results. However, exact location losses devices is often obscured by various competing processes when measurements analyzed. Here, we show via...
Generalizing the mode-coupling theory for ideal liquid-glass transitions, equations of motion are derived correlation functions describing glassy dynamics a diatomic probe molecule immersed in simple glass-forming system. The is described interaction-site representation and solved dumbbell consisting two fused hard spheres hard-sphere results molecule's arrested position glass state reorientational correlators angular-momentum index l=1 l=2 near transition compared with those obtained...
Within the mode-coupling theory (MCT) for evolution of structural relaxation in glass-forming liquids, correlation functions and susceptibility spectra are calculated characterizing rotational dynamics a top-down symmetric dumbbell molecule, consisting two fused hard spheres immersed hard-sphere system. It is found that sufficiently large elongations, probe molecule follows same universal glass-transition scenario as known from MCT results simple liquids. The alpha-relaxation process...
High bandgap semitransparent solar cells based on CH 3 NH PbBr perovskites are attractive for building integration, tandem cells, and electrochemical applications. The lack of control the perovskite growth limit exploitation ‐based cells. Herein, a post‐treatment is carried out after initial crystallization methylamine gas that drastically enhances quality leading to highly crystalline film with improved average visible transmittance (AVT) close 56%. Opaque devices showed outstanding results...
Chemically processed methylammonium tin-triiodide (CH3NH3SnI3) films include Sn in different oxidation states, leading to poor stability and low power conversion efficiency of the resulting solar cells (PSCs). The development absorbers with [2+] only has been identified as one critical steps develop all Sn-based devices. Here, we report on coevaporation CH3NH3I SnI2 obtain being preferred state [+2] confirmed by X-ray photoelectron spectroscopy. [4+]-free exhibit smooth highly crystalline...
We demonstrate a versatile technique to generate broadband optical frequency comb source in the C-band. This is accomplished by nonlinear spectral broadening of phase modulated driven dual offset locked carriers. The locking achieved setting up heterodyne loop lock two electro-optic 25 GHz combs sourced from individual seed carriers 100 GHz, within 6.7 MHz each other. realize highly fiber after suitable amplification obtain an equalized, nonlinearly broadened comb. $\sim 86 $∼86 lines 20 dB...
Abstract A nanocomposite consisting of a unique combination optically active materials, that is, an inorganic–organic (IO) layered hybrid and porous silicon (PS), is prepared using simple but effective three‐step electrochemical method. X‐ray diffraction, energy‐dispersive spectroscopy, photoluminescence spectral analysis suggest the IO (R‐MX 4 ‐type 2D perovskite, where R represents organic compound, M divalent metal ion, X halide) conveniently incorporated into interstitial spaces...
Dye-sensitized solar cells (DSCs) have gained great attention in recent years due to their low-cost fabrication, flexibility, and high power conversion efficiency. In a DSC, interfaces between the dye charge-transport materials, interface electrostatics becomes key factor determining overall performance of cell. Liquid-electrolyte-based DSCs suffer from low stability, electrolyte leakage, and, some cases, electrode corrosion. Replacing liquid with solid semiconducting material leads poor...
We demonstrate a multi-wavelength source with high repetition rate of 25 GHz, spanning the entire C-band, which 124 lines lie within 10 dB bandwidth. exploit spectral and temporal properties dual carrier electro-optic combs to simultaneously enhance self-phase modulation (SPM) based broadening increase stimulated Brillouin scattering (SBS) threshold. Dual are generated through spectrally separated narrow linewidth carriers. They broadened in highly nonlinear fiber after amplification an...
The short-range translational and orientational order around a rigid linear solute molecule immersed in dense simple liquid is investigated within the Percus–Yevick theory. correlations induced by anisotropic solute–solvent interaction are analyzed spherical harmonics expansion. smearing of local shell structure studied for increasingly model molecules different densities.
The quasi-lattice theory (QLT) is utilized for the prediction of temperature and concentration dependence thermodynamic properties molten CdSn alloys. At first, analytical expressions are employed to reckon excess Gibbs free energy mixing, activity, enthalpy mixing entropy as well fluctuations, short range-order parameter stability function ofCdSn melts at 773 K. For this, model parameters i.e. size ratio order assessed using experimental data CdSnmelts theoretical values functions in...
Inorganic–organic hybrid perovskites offer wide optical absorption, long charge carrier diffusion length, and high optical-to-electrical conversion, enabling more than 25% efficiency of single-junction perovskite solar cells. All-perovskite four-terminal (4T) tandem cells have gained great attention because solution-processability potentially without a need for current-matching between subcells. To make the best use architecture, subcell bandgaps thicknesses must be optimized. This study...