A5043062634- Perovskite Materials and Applications
- Conducting polymers and applications
- Organic Electronics and Photovoltaics
- Solid-state spectroscopy and crystallography
- Advanced Memory and Neural Computing
- Chalcogenide Semiconductor Thin Films
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Luminescence and Fluorescent Materials
- Organic Light-Emitting Diodes Research
- Quantum Dots Synthesis And Properties
- 2D Materials and Applications
- ZnO doping and properties
- Molecular Junctions and Nanostructures
- Advanced Sensor and Energy Harvesting Materials
- Electronic and Structural Properties of Oxides
- Supramolecular Self-Assembly in Materials
- Machine Learning in Materials Science
- Organic and Molecular Conductors Research
- Covalent Organic Framework Applications
- Thin-Film Transistor Technologies
- Optical properties and cooling technologies in crystalline materials
- Luminescence Properties of Advanced Materials
- Analytical Chemistry and Sensors
- Synthesis and Properties of Aromatic Compounds
National Institute of Science Education and Research
2021-2025
Homi Bhabha National Institute
2023-2024
University of Cambridge
2016-2023
Institute of Minerals and Materials Technology
2019-2020
Council of Scientific and Industrial Research
2020
Central Institute of Plastics Engineering and Technology
2018-2019
Jawaharlal Nehru Centre for Advanced Scientific Research
2010-2018
Bangalore University
2014
National Chemical Laboratory
2010
K S Hegde Medical Academy
2009
Solution-processable metal halide perovskites show immense promise for use in photovoltaics and other optoelectronic applications. The ability to tune their bandgap by alloying various anions (for example, CH3NH3Pb(I1–xBrx)3, 0 < x 1) is however hampered the reversible photoinduced formation of sub-bandgap emissive states. We find that ion segregation takes place via defects, resulting iodide-rich low-bandgap regions close illuminated surface film. This may be driven strong gradient carrier...
Fundamental understanding of the charge transport physics hybrid lead halide perovskite semiconductors is important for advancing their use in high-performance optoelectronics. We field-effect transistors (FETs) to probe mechanism thin films methylammonium iodide (MAPbI3). show that through optimization thin-film microstructure and source-drain contact modifications, it possible significantly minimize instability hysteresis FET characteristics demonstrate an electron mobility (μFET) 0.5...
The influence of monovalent cation halide additives on the optical, excitonic, and electrical properties CH 3 NH PbI perovskite is reported. Monovalent with similar ionic radii to Pb 2+ , including Cu + Na Ag have been added explore possibility doping. Significant reduction sub‐bandgap optical absorption lower energetic disorder along a shift in Fermi level presence these cations has observed. bulk hole mobility additive‐based perovskites as estimated using space charge limited current...
Hysteresis-free operational stable perovskite FETs is demonstrated through ionic passivation and crystal modification.
One source of instability in perovskite solar cells (PSCs) is interfacial defects, particularly those that exist between the and hole transport layer (HTL). We demonstrate thermally evaporated dopant-free tetracene (120 nm) on top layer, capped with a lithium-doped Spiro-OMeTAD (200 gold electrode, offers an excellent hole-extracting stack minimal defect levels. For interfaced these graded HTLs mesoporous TiO2 electron-extracting its photoluminescence yield reaches 15% compared to 5% for...
While the mechanism of self-assembly π-conjugated molecules has been well studied to gain control over structure and functionality supramolecular polymers, intermolecular interactions underpinning it are poorly understood. Here, we study perylene bisimide derivatives possessing dipolar carbonate groups as linkers. It was observed that combination linkers cholesterol/dihydrocholesterol self-assembling moieties led a cooperative self-assembly. Atomistic molecular dynamics simulations an...
Reliable and ultrasensitive detection of mercury ions is paramount importance for toxicology assessment, environmental protection, human health. Herein, we present a novel optoelectronic approach based on nanoarchitectonics small-molecule templated DNA system that consists an adenine (A)-conjugated small organic semiconductor (BNA) deoxyribo-oligothymidine (dTn). This mutually dynamic chiral coassembly (BNAn-dTn) with tunable chiroptical, morphological, electrical properties tapped in to...
The possibility of designing programmable thin-film supramolecular structures with spontaneous polarization widens the utility facile chemistry. Although a range low molecular mass single crystals has been shown to exhibit ferroelectric polarization, demonstration stimuli-responsive, thin-film, solution-processable materials is rare. We introduce aromatic π-electron donor-acceptor systems responsive multiple stimuli that undergo chiral mixed-stack charge-transfer (CT) coassembly through...
We report on the optimization of interfacial properties titania in mesoscopic CH3NH3PbI3 solar cells. Modification mesoporous TiO2 film by TiCl4 treatment substantially reduced surface traps, as is evident from sharpness absorption edge with a significant reduction Urbach energy (from 320 to 140 meV) determined photothermal deflection spectroscopy, and led an order magnitude enhancement bulk electron mobility corresponding decrease transport activation 170 90 within device. After...
Optoelectronic devices based on metal halide perovskites, including solar cells and light-emitting diodes, have attracted tremendous research attention globally in the last decade. Due to their potential achieve high carrier mobilities, organic-inorganic hybrid perovskite materials can enable high-performance, solution-processed field-effect transistors (FETs) for next-generation, low-cost, flexible electronic circuits displays. However, performance of FETs is hampered predominantly by...
Abstract Materials and technology development for designing innovative efficient X‐ray radiation detectors is of utmost importance a wide range applications ranging from security to medical imaging. Here, highly sensitive direct based on novel cesium (Cs)‐based triple cation mixed halide perovskite thin films are reported. Despite being in film form, the devices exhibit remarkably high sensitivity (3.7 ± 0.1) µC Gy −1 cm −2 under short‐circuit conditions. At small reverse bias 0.4 V, further...
Abstract Halide double perovskites have gained significant attention, owing to their composition of low‐toxicity elements, stability in air, and recent demonstrations long charge‐carrier lifetimes that can exceed 1 µs. In particular, Cs 2 AgBiBr 6 is the subject many investigations photovoltaic devices. However, efficiencies solar cells based on this perovskite are still far from theoretical efficiency limit material. Here, role grain size optoelectronic properties thin films investigated....
Although many examples of mechanically flexible crystals are currently known, their utility in all-flexible devices is not yet adequately demonstrated, despite immense potential for fabricating high performance devices. Here, we report two alkylated diketopyrrolopyrrole (DPP) semiconducting single crystals, one which displays impressive elastic mechanical flexibility whilst the other brittle. Using crystal structures and density functional theory (DFT) calculations, show that methylated...
Despite the rapid rise in performance of a variety perovskite optoelectronic devices with vertical charge transport, effects ion migration remain common and longstanding Achilles' heel limiting long-term operational stability lead halide devices. However, there is still limited understanding impact tin (Sn) substitution on dynamics (Pb) perovskites. Here, we employ scan-rate-dependent current-voltage measurements Pb mixed Pb-Sn solar cells to show that short circuit current losses at lower...
The advent of new-class high-mobility semiconducting polymers opens up a window to address fundamental issues in electrical transport mechanism such as hopping between localized states versus extended state conduction. Here, we investigate the origin ultra-low degree disorder (~ 16 meV) and band-like negative temperature (T) coefficient field effect electron mobility high performance diketopyrrolopyrrole (DPP)-based polymer. Models based on framework edge (ME) with exponential density are...
Mixed lead–tin halide perovskites have sufficiently low bandgaps (∼1.2 eV) to be promising absorbers for perovskite–perovskite tandem solar cells. Previous reports on typically shown poor optoelectronic properties compared neat lead counterparts: short photoluminescence lifetimes (<100 ns) and quantum efficiencies (<1%). Here, we obtain films with carrier exceeding 1 μs and, through addition of small quantities zinc iodide the precursor solutions, under illumination intensities 2.5%. The...
Abstract Precise control of the microstructure in organic semiconductors (OSCs) is essential for developing high‐performance electronic devices. Here, a comprehensive charge transport characterization two recently reported rigid‐rod conjugated polymers that do not contain single bonds main chain reported. It demonstrated molecular design polymer makes it possible to achieve an extended linear backbone structure, which can be directly visualized by high‐resolution scanning tunneling...
The charge transport–limiting factors in conjugated polymers without single-bond linkages the backbone have been identified.
Development of new n-type semiconductors with tunable band gap and dielectric constant has significant implication in dissociating bound charge carrier relevant for demonstrating high performance optoelectronic devices. Boron-β-thioketonates (MTDKB), analogues to boron-β-diketonates containing a sulfur atom the framework β-diketones were synthesized. Bulk transport measurement exhibited an outstanding bulk electron mobility ≈0.003 cm2 V-1 s-1 , which is among best values reported till date...
Abstract Molecular ferroelectrics are of enormous interest due to their ease synthesis and simplicity in device fabrication. Here, the non‐volatile memory effect a polycrystalline thin film single‐component ferroelectric material naphthalene monoimide (NMI), 6‐bromo‐2‐(1‐phenylethyl)‐1H‐benzo[de]isoquinoline‐1,3(2H)‐dione ( NMI‐ R Bn ), obtained by introducing enantiomeric α‐methylbenzyl ) substituents on NMI backbone is demonstrated. Both S derivatives crystallized monoclinic P 2 1 space...