A5072223361- Perovskite Materials and Applications
- 2D Materials and Applications
- Quantum Dots Synthesis And Properties
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Photochemistry and Electron Transfer Studies
- Porphyrin and Phthalocyanine Chemistry
- Molecular Junctions and Nanostructures
- Radical Photochemical Reactions
- Advanced Photocatalysis Techniques
- Organic Electronics and Photovoltaics
- Lanthanide and Transition Metal Complexes
- Gold and Silver Nanoparticles Synthesis and Applications
- Graphene research and applications
- Solid-state spectroscopy and crystallography
- Integrated Circuits and Semiconductor Failure Analysis
- Silicon and Solar Cell Technologies
- Liquid Crystal Research Advancements
- Conducting polymers and applications
- DNA and Nucleic Acid Chemistry
- Pharmaceutical and Antibiotic Environmental Impacts
- Luminescence and Fluorescent Materials
- Genomics and Chromatin Dynamics
- Prenatal Substance Exposure Effects
- Organic Light-Emitting Diodes Research
Northwestern University
2019-2022
University of Miami
2013-2017
American Orchid Society
2017
Savitribai Phule Pune University
1991
ConspectusThe electronic dimensionality of a material is defined by the number spatial degrees confinement its wave function. Low-dimensional semiconductor nanomaterials with at least one degree have optoelectronic properties that are tunable size and environment (dielectric chemical) particular interest for applications such as light detection, harvesting, photocatalysis. By combining differing dimensionalities, mixed-dimensional heterojunctions (MDHJs) exploit desirable characteristics...
Mixed-dimensional heterojunctions (MDHJs) combine the characteristics of component materials such as discrete orbital energies zero-dimensional (0D) molecules and extended band structure two-dimensional (2D) semiconductors. Here, time-resolved spectroscopy reveals sub-picosecond photoinduced hole-transfer sub-320 fs electron-transfer processes at interfaces type-II copper free-base phthalocyanine/monolayer MoS2 MDHJs. In CuPc/MoS2 heterojunctions, charge separation lasts long 70 ns, which is...
Hybrid halide perovskites consisting of corner-sharing metal octahedra and small cuboctahedral cages filled with counter cations have proven to be prominent candidates for many high-performance optoelectronic devices. The stability limits their three-dimensional perovskite framework are defined by the size range present in structure. In some cases, perovskite-type structure can extended even when counterions violate shape requirements, as is case so-called "hollow" perovskites. this work, we...
This paper describes reversible "on–off" switching of the photoluminescence (PL) intensity CdSe quantum dots (QDs), mediated by photochromic furylfulgide carboxylate (FFC) molecules chemisorbed to surfaces QDs. Repeated cycles UV and visible illumination switch FFC between "closed" "open" isomers. Reversible QDs' PL >80% is enabled different rates yields PL-quenching photoinduced electron transfer (PET) from QDs respective difference consistent with cyclic voltammetry measurements density...
Lattice defects play an important role in determining the optical and electrical properties of monolayer semiconductors such as MoS2. Although structures various MoS2 are well studied, little is known about nature fluorescent defect species their interaction with molecular adsorbates. In this study, quenching low-temperature photoluminescence (PL) investigated following deposition metallophthalocyanines (MPcs). The found to significantly depend on identity phthalocyanine metal, efficiency...
As the number of hybrid systems comprising quantum-confined semiconductor nanocrystals and molecules continues to grow, so does need accurately describe interfacial energy charge transfer in these systems. The earliest work often successfully captured at least qualitative trends rates processes using well-known results from Förster, Dexter, Marcus theories, but recent studies have showcased how unique properties drive (EnT) (CT) diverge familiar trends. This review first describes...
Cesium-halide perovskite quantum dots (QDs) have gained tremendous interest as emitters in information processing applications due to their optical and photophysical properties. However, engineering excitonic states requires a deep knowledge of the coherent dynamics excitons at single-particle level. Here, we use femtosecond time-resolved two-photon near-field scanning microscopy (NSOM) reveal coherences involving single cesium lead bromide QD (CsPbBr3) room temperature. We show that,...
The optoelectronic properties of organic thin films are strongly dependent on their molecular orientation and packing, which in turn is sensitive to the underlying substrate. Hexagonal boron nitride (hBN) other van der Waals (vdW) materials known template different film growth modalities from conventional inorganic substrates such as SiO2. Here, morphology temperature-dependent optical pentacene grown hBN reported. Pentacene deposited forms large-grain with a π-face-on unlike dendritic...
Trivalent lanthanide ions (Ln3+) have electronically isolated f-orbitals that support excited states, which, due to their ultra-narrow emission and long spin coherence lifetimes, are potentially suitable as hosts for qubits. These states must however be generated through photosensitization the low-absorption cross sections of Ln3+. This paper describes mechanism Yb3+ Sm3+ by CsPbCl3 perovskite nanocrystal (NC) host matrices, examination photophysical processes in NCs doped with seven...
In eukaryotic cells, Flap endonuclease 1 (FEN1) is a major structure-specific that processes 5' flapped structures during maturation of lagging strand DNA synthesis, long patch base excision repair, and rescue stalled replication forks. Here we report fanconi anemia complementation group A protein (FANCA), recognizes flap involved in repair maintenance forks, constantly stimulates FEN1-mediated incision both RNA flaps. Kinetic analyses indicate FANCA FEN1 by increasing the turnover rate...
This study explores the mechanisms of long-range energy transfer (EnT) from a self-assembled film CdSe/ZnS core–shell quantum dots (QDs) to exfoliated black phosphorus (BP) nanoflakes through an AlOx encapsulation layer variable thickness. The dependence EnT rate on donor–acceptor distance, d, scales as ∼d–2.3, which is shallower than expected scaling for Förster-type zero-dimensional (0D) donor 2D or 3D acceptor. Electrodynamic simulations reveal that efficient primarily attributable high...
Intermittent periods of low light emission ("blinking") and time-dependent spectra (spectral diffusion, SD) have proven to be major obstacles the adoption colloidal semiconductor nanocrystals as quantum emitters. One clue mechanisms behind these two phenomena is how they are related, which difficult determine at time scales faster than can captured using a spectrometer (∼100 ms). This work utilizes spectral correlations access range from 10 μs s determines that, for quasi-2D CdSe/CdS...
We investigated the photochemistry of ternary complexes a cucurbit[8]uril host and donor–acceptor stilbene guests. found that slow back electron transfer rates allow [2 + 2] photocycloadditions to proceed after photoinitiated charge transfer.
A comparative study is made on the radiation damage caused by 14 MeV neutrons and 1 electrons in crystalline silicon measuring Hall mobility, carrier concentration, energies of defect centres minority lifetime. For both are found to be almost identical but observed degradation mobility large neutron-irradiated marginal electron-irradiated silicon. The coefficient for higher three orders magnitude compared with that electrons.
A hexylalkoxy dipolar D-A-A molecule [7-(4-N,N-(bis(4-hexyloxyphenyl)amino)phenyl)-2,1,3-(benzothia-diazol-4-yl)methylene]propane-dinitrile, (C6-TPA-BT-CN) has been synthesized and the photophysics studied via femtosecond transient absorption spectroscopy (FsTA) in toluene amorphous liquid crystalline spherulite thin films. Two macromolecular phases (banded, non-banded) were observed through concentration dependent, solution processing techniques are birefringent with a negative sign of...
Drug donation programs increase medication availability and encourage proper pharmaceutical disposal. Proper disposal decreases the potential human environmental risk posed by presence of compounds in water bodies. Furthermore, public health hazard drug abuse is mitigated due to decreased drugs. The preferred method through take-back programs, which medications are returned local pharmacies, law enforcement, or other responsible agencies. Take-back can also involve donation, states such as...
Low energy vibrations in the excited state have been hypothesized to play an important role quickly and efficiently generating free charges bulk heterojunctions of some conjugated polymer systems. While time-resolved vibrational spectroscopies seemingly are well poised address relationship between kinetics motions after initial photoexcitation, uncertainty measurement arises due overlapping signals difficulties assigning observed oscillatory molecular response. Here, we demonstrate a high...
Host-guest 2:1 complexation of photoreactive alkene guests improves the selectivity [2+2] photodimerizations by templating orientation prior to irradiation. chemistry can also provide 1:1:1 complexes through inclusion electronically complementary donor and acceptor guests, but photoreactivity such has not been investigated. We imagined that could enable selective cross-[2+2] photocycloadditions between stilbenes. In pursuit this strategy, we investigated a series stilbenes found with...
Host-guest 2:1 complexation of photoreactive alkene guests improves the selectivity [2+2] photodimerizations by templating orientation prior to irradiation. chemistry can also provide 1:1:1 complexes through inclusion electronically complementary donor and acceptor guests, but photoreactivity such has not been investigated. In this work, we investigated a series stilbenes found with cucurbit[8]uril that exhibited charge-transfer (CT) absorption bands in visible near-IR regions. Irradiation...
The electronically isolated f-orbitals of Ln3+ ions endow these species ultranarrow (atom-like) emission with a long lifetime, which are suitable for the optical generation and propagation spin qubits, even after coordination inside semiconductor matrices. To overcome low extinction coefficient ions, indirect sensitization via energy transfer from perovskite quantum dots (QDs) is performed through partial substitution matrix ions. Here, we suggest charge type intermediate involved in...