A5084839653- Quantum Dots Synthesis And Properties
- Chalcogenide Semiconductor Thin Films
- Gold and Silver Nanoparticles Synthesis and Applications
- Perovskite Materials and Applications
- Plasmonic and Surface Plasmon Research
- Semiconductor Quantum Structures and Devices
- 2D Materials and Applications
- Machine Learning in Materials Science
- Solid-state spectroscopy and crystallography
- Chemical Safety and Risk Management
- Nanomaterials for catalytic reactions
- Various Chemistry Research Topics
- Electronic and Structural Properties of Oxides
- Chemistry and Chemical Engineering
- Semiconductor Lasers and Optical Devices
- Mechanical and Optical Resonators
- Quantum optics and atomic interactions
- Near-Field Optical Microscopy
- Spectroscopy and Quantum Chemical Studies
- Strong Light-Matter Interactions
- Thermography and Photoacoustic Techniques
- Photonic and Optical Devices
- Laser-Matter Interactions and Applications
- Copper-based nanomaterials and applications
- Nanomaterials and Printing Technologies
Northwestern University
2019-2025
Significant interest exists in lead trihalides that present the perovskite structure owing to their demonstrated potential photovoltaic, lasing, and display applications. These materials are also notable for unusual phase behavior often displaying easily accessible transitions. In this work, time-resolved X-ray diffraction, performed on cesium bromide nanocrystals, maps lattice response controlled excitation fluence. nanocrystals undergo a reversible, photoinduced orthorhombic-to-cubic...
The tailored spatial polarization of coherent light beams is important for applications ranging from microscopy to biophysics quantum optics. Miniaturized sources are needed integrated, on-chip photonic devices with desired vector beams; however, this issue unresolved because most lasers rely on bulky optical elements achieve such control. Here, we report dot-plasmon engineered patterns controllable by near-field coupling colloidal dots metal nanoparticles. Conformal coating CdSe-CdS...
We report how the direction of quantum dot (QD) lasing can be engineered by exploiting high-symmetry points in plasmonic nanoparticle (NP) lattices. The nanolaser architecture consists CdSe-CdS core-shell QD layers conformally coated on two-dimensional square arrays Ag NPs. Using waveguide-surface lattice resonances (W-SLRs) near Δ point Brillouin zone as optical feedback, we achieved from gain CdS shells at off-normal emission angles. Changing periodicity lattices enables other (Γ or M) to...
Methylammonium lead iodide (MAPbI3) perovskite nanocrystals (NCs) offer desirable optoelectronic properties with prospective utility in photovoltaics, lasers, and light-emitting diodes (LEDs). Structural rearrangements of MAPbI3 response to photoexcitation, such as lattice distortions phase transitions, are particular interest, these engender long carrier lifetime bolster diffusion. Here, we use variable temperature X-ray diffraction (XRD) synchrotron-based transient (TRXRD) investigate...
Zero-dimensional PbSe quantum dots are heterogeneously nucleated and grown onto two-dimensional zincblende CdSe nanoplatelets. Electron microscopy shows ad-grown predominantly decorate edges corners of the Spectroscopic characterizations relate type I electronic alignment as demonstrated via photoluminescence excitation spectroscopy enhancement near-infrared emission. Transient absorption convey ultrafast transfer excitons to lower energy semiconductor dots. These structures combine benefits...
We report spin-polarized transient absorption for colloidal CdSe nanoplatelets as functions of thickness (2-6 monolayer thickness) and core/shell motif. Using electro-optical modulation co- cross-polarization pump-probe combinations, we sensitively observe transitions. Core-only exhibit few-picosecond spin lifetimes that weakly increase with layer thickness. The spectral content differenced signals indicate biexciton binding energies decrease increasing smaller values than previously...
Lattice plasmon cavity modes combined with optical gain can exhibit directional and tunable lasing emission at room temperature. However, the mechanistic details governing dynamics before action are not understood. This paper describes how long photon lifetimes of lattice be correlated ultrafast amplified spontaneous emission. Lasing from band-edge plasmons propagating showed rise times on order tens picoseconds, during which inverted population in was first generated then followed by energy...
Metal nitrides are a promising non-toxic, inexpensive, and durable material for photothermal applications. The properties of titanium nitride measured using time-resolved X-ray diffraction following optical excitation.
Colloidal semiconductor nanocrystals offer bandgap tunability, high photoluminescence quantum yield, and colloidal processing of benefit to optoelectronics, however rapid nonradiative Auger recombination (AR) deleteriously affects device efficiencies at elevated excitation intensities. AR is understood transition from temperature-dependent behavior in bulk semiconductors temperature-independent zero-dimensional dots (QDs) as a result discretized band structure that facilitates satisfaction...
This paper describes low-threshold lasing from colloidal CdSe nanoplatelets (NPLs) coated on two-dimensional plasmonic cavities composed of aluminum nanoparticles (NPs). We designed the NP lattice to support a spectrally narrow surface resonance whose wavelength overlapped with amplified spontaneous emission (ASE) NPLs. Al lattices NPL thin films were optically pumped and exhibited in normal direction low angular divergence, spectral line width (∼1 nm), threshold ∼200 μJ/cm2. Nonlinear light...
CuInSe2 nanocrystals offer promise for optoelectronics including thin-film photovoltaics and printed electronics. Additive manufacturing methods such as photonic curing controllably sinter particles into quasi-continuous films improved device performance. To gain understanding of nanocrystal response under processing conditions, we investigate impacts photoexcitation on colloidal lattices via time-resolved X-ray diffraction. We probe three sizes two capping ligands (oleylamine inorganic S2–)...
Two-dimensional cadmium selenide nanoplatelets (NPLs) exhibit large absorption cross sections and homogeneously broadened band-edge transitions that offer utility in wide-ranging optoelectronic applications. Here, we examine the temperature-dependence of amplified spontaneous emission (ASE) 4- 5-monolayer thick NPLs show threshold for close-packed (neat) films decreases with decreasing temperature by a factor 2-10 relative to ambient owing extrinsic (trapping) intrinsic (phonon-derived line...
Symmetry control is essential for realizing unconventional properties, such as ferroelectricity, nonlinear optical responses, and complex topological order, thus it holds promise the design of emerging quantum photonic systems. Nevertheless, fast reversible symmetry in materials remains a challenge, especially nanoscale Here, changes are unveiled colloidal lead chalcogenide dots on picosecond timescales. Using combination ultrafast electron diffraction total X-ray scattering, conjunction...
Nanoplatelets (NPLs)—colloidally synthesized, spatially anisotropic, two-dimensional semiconductor quantum wells—are of intense interest owing to exceptionally narrow transition line widths, coupled with solution processability and bandgap tunability. However, given large surface areas undercoordinated bonding at facet corners edges, excitation under sufficient intensities may induce anisotropic structural instabilities that impact desired properties. We employ time-resolved X-ray...
Large and faceted nanoparticles, such as gold bipyramids, presently require synthesis using alkyl ammonium halide ligands in aqueous conditions to stabilize the structure, which impedes subsequent transfer suspension of nanoparticles low polarity solvents despite success with few nanometer shapes spheres. Phase methodologies present a feasible avenue maintain colloidal stability suspensions move high surface energy particles into organic solvent environments. Here, we method yield stable...
Symmetry control is essential for realizing unconventional properties, such as ferroelectricity, nonlinear optical responses, and complex topological order, thus it holds promise the design of emerging quantum photonic systems. Nevertheless, fast reversible symmetry in materials remains a challenge, especially nanoscale Here, we unveil changes colloidal lead chalcogenide dots on picosecond timescales. Using combination ultrafast electron diffraction total X-ray scattering, conjunction with...
Coherent vibrations detected in optical experiments can offer insights into material properties and electronic interactions, but also yield complex time-dependent signatures, especially hybridized systems. Here, we adapt techniques from studies on vibrational wave packets molecules to analyze the signatures of coherent acoustic phonons nanoparticles. This strategy enables us better understand implications energetic changes induced by phonons. We then apply this approach systems that target...
ADVERTISEMENT RETURN TO ISSUEPREVHighlightNEXTHighlights: Correlating Molecular Structures to Physical Properties, Ammonium Nitrate in the News, Tools and Databases, MoreSubmit contributions [email protected] be coauthored, or share ideas on social media with #SafetyHighlightsFrankie Wood-Black*Frankie Wood-BlackSophic Pursuits, Tonkawa, Oklahoma 74653, United States*E-mail: protected]More by Frankie Wood-Blackhttp://orcid.org/0000-0001-7768-2140, Nicolas E. WatkinsNicolas WatkinsDepartment...
We report spin-polarized transient absorption for colloidal CdSe nanoplatelets as functions of thickness (2 to 6 monolayer thickness) and core/shell motif. Using electro-optical modulation co- cross-polarization pump-probe combinations, we sensitively observe transitions. Core-only exhibit few-picosecond spin lifetimes that weakly increase with layer thickness. Spectral content differenced signals indicate biexciton binding energies decrease increasing smaller values than previously...