A5053291314- Nonlinear Optical Materials Studies
- Photonic and Optical Devices
- Nonlinear Optical Materials Research
- Crystallization and Solubility Studies
- Photonic Crystals and Applications
- Luminescence and Fluorescent Materials
- Photochemistry and Electron Transfer Studies
- Organic Electronics and Photovoltaics
- Nanocluster Synthesis and Applications
- Photochromic and Fluorescence Chemistry
- Spectroscopy and Quantum Chemical Studies
- Microfluidic and Capillary Electrophoresis Applications
- X-ray Diffraction in Crystallography
- Semiconductor Lasers and Optical Devices
- Surfactants and Colloidal Systems
- Porphyrin and Phthalocyanine Chemistry
- Perovskite Materials and Applications
- Conducting polymers and applications
- Magnetism in coordination complexes
- Organic and Molecular Conductors Research
- Lanthanide and Transition Metal Complexes
- Random lasers and scattering media
- Nanofabrication and Lithography Techniques
- Polydiacetylene-based materials and applications
- Electrowetting and Microfluidic Technologies
Georgetown University
2013-2024
United States Naval Research Laboratory
2010
BASF (United States)
1999-2003
BASF (Germany)
1991-2002
Yokkaichi University
1998-1999
National Institute for Materials Science
1996-1998
National Institute of Advanced Industrial Science and Technology
1995
Carnegie Mellon University
1991
Abstract Here the influence that 1‐(3‐hexoxycarbonyl)propyl‐1‐phenyl‐[6,6]‐Lu 3 N@C 81 , Lu 80 –PCBH, a novel acceptor material, has on active layer morphology and performance of organic photovoltaic (OPV) devices using this material is reported. Polymer/fullerene blend films with poly(3‐hexylthiophene), P3HT, donor –PCBH are studied absorption spectroscopy, grazing incident X‐ray diffraction photocurrent spectra devices. Due to smaller molecular orbital offset OPV built display increased...
Atomically thin transition metal dichalcogenides (TMDs) are ideal candidates for ultrathin optoelectronics that is flexible and semitransparent. Photodetectors based on TMDs show remarkable performance, with responsivity detectivity higher than 10^3 A/W 10^12 Jones, respectively, but they plagued by response times as slow several tens of seconds. Although it well established gas adsorbates such water oxygen create charge traps significantly increase both the time, underlying mechanism still...
Single photons produced by fundamentally dissimilar physical processes will in general not be indistinguishable. We show how from a quantum dot and parametric down-conversion nonlinear crystal can manipulated to The measured two-photon coalescence probability is 16%, limited quantum-dot decoherence. Temporal filtering the coherence time accounting for detector response increases this 61% while retaining 25% of events. This technique connect different elements scalable network.
The nonlinear optical (NLO) properties of gold nanoparticles embedded in polyelectrolyte multilayer thin films, particular the dispersion third-order nonlinearity and its relaxation around plasmon band, have been investigated by femtosecond wavelength dispersive degenerate four wave mixing. experimental results are discussed terms a simple model for nanoparticle systems. demonstrate that not only is color metallic dominated surface resonance but plasmons govern NLO phenomena as well.
The crystallization of monosodium urate monohydrate (MSU) in the synovial fluid has long been associated with joint disease gout, which is characterized by recurring attacks pain and inflammation within joints. In this work, situ atomic force microscopy (AFM) on single crystal (010) MSU surfaces dynamic light scattering were used complementarily to investigate growth 2–10 mM solutions under model physiological conditions (37 °C, pH = 7.4, 150 NaCl). solution regime, rates normal surface...
Organic ligands with carboxylate functionalities have been shown to affect the solubility, speciation, and overall chemical behavior of tetravalent metal ions. While many reports focused on actinide complexation by relatively simple monocarboxylates such as amino acids, in this work we examined Th(IV) U(IV) 4-hydroxybenzoic acid water aim understanding impact that organic backbone has solution solid state structural chemistry thorium(IV) uranium(IV) complexes. Two compounds general formula...
Inflammatory responses associated with ischemia/reperfusion injury (IRI) play a central role in alloimmunity and transplant outcomes. A key event driving these inflammatory is the burst of reactive oxygen species (ROS), hydrogen peroxide (H2 O2 ) as most abundant form that occurs result surgical implantation donor organ. Here, we used syngeneic rat renal IRI model to evaluate therapeutic properties APP-103, polyoxalate-based copolymer molecule containing vanillyl alcohol (VA) exhibits high...
Metal-oxo clusters have been used as building blocks to form hybrid nanomaterials and evaluated potential MRI contrast agents. We synthesized a biocompatible copolymer based on water stable, nontoxic, mixed-metal-oxo cluster, Mn8Fe4O12(L)16(H2O)4, where L is acetate or vinyl benzoic acid, styrene. The cluster alone was screened by NMR for relaxivity found be promising T2 agent, with r1 = 2.3 mM(-1) s(-1) r2 29.5 s(-1). Initial cell studies two human prostate cancer lines, DU-145 LNCap,...
Algorithms for effective modeling of optical propagation in three- dimensional waveguide structures are critical the design photonic devices. We present a three-dimensional (3-D) wide-angle beam method (WA-BPM) using Hoekstra's scheme. A sparse matrix algebraic equation is formed and solved iterative methods. The applicability, accuracy effectiveness our demonstrated by applying it to simulations propagation, along with technique shifting simulation window reduce dimension numerical...
Self-organization of molecules in solution is an important natural and synthetic process, particular for the preparation nanomaterials. However, mechanism growth solution-based nanoparticle formation not always well understood. We present results that clarify these mechanisms solutions magnesium phthalocyanine which self-organization induced by addition a miscible nonsolvent. From simultaneous measurements sizes growing nanoparticles photon correlation spectroscopy molecular concentration...
Surface attachment of the manganese–oxo cluster known as Mn-12 provided aqueous solution stabilization that allowed investigation use an MRI contrast agent.
We demonstrate that indium tin oxide nanowires (ITO NWs) and cationic polymer-modified ITO NWs configured in a network format can be used as high performing UV/vis photodetectors. The photovoltage response of is much higher than similarly constructed devices made from oxide, zinc nanostructures. NW mesh-based exhibit substantial (31-100 mV under illumination with 1.14 mW 543 nm laser) photocurrent (225-325 μA at 3 V). time the fast rise 20-30 μs decay 1.5-3.7 ms when probed 355 pulsed laser....
It was demonstrated that the third-order optical nonlinearity of polymer films could be reversibly controlled by photochromic conversion and following J-aggregate formation spiropyran embedded in an inert matrix. Patterns consisting areas with high low nonlinear activities were prepared imagewise exposure followed thermal treatment to form thermally stable J aggregates photoinduced merocyanine exposed area. This system useful developing new unconventional devices based on nonlinearities,...
Nanoparticles of the molecular crystal naphthalene were prepared through a solvent exchange process. The gradual replacement acetone with water induces aggregation and precipitation naphthalene. Near phase boundary in this ternary system we found regions which nanocrystals diameters on order 100s nanometers formed. particle size vs time after mixing was measured using dynamic light scattering, showing progress growth crystals.
Polydiacetylene microcrystals in a water suspension or polymer matrix were prepared by simple precipitation procedure order to obtain thin samples with good optical quality maintaining the characteristics of crystalline materials. The nonlinear refraction, n<SUB>2</SUB>, and absorption, (beta) , around exciton peak measured z-scan method using tunable picosecond laser. signs n<SUB>2</SUB> are positive/negative at wavelengths shorter/longer than strong saturable which is negative, observed...
Numerous precipitation methods for creating nanoparticle dispersions that are based on mixing a solution with miscible nonsolvent have been developed. Here, we show polymer particles, the formation is highly dependent rate of mixing. We also demonstrate importance glass transition polymers particle formation. A simple model droplet during provides satisfactory description observed dependence size molecular weight, concentration, solvent ratio, and conditions.
Charge transfer (CT) cocrystals, molecular crystals composed of electron donating and accepting species, are being developed for applications in optoelectronics. Here we present optical electronic characterization the CT cocrystal phenothiazine–tetracyanoquinodimethane (PTZ–TCNQ). This material has a broad NIR absorption peak with an band edge less than 0.6 eV. We used density functional theory calculations to identify origin low energy states changes Raman spectra. also demonstrate...
Nanocapsules, consisting of a solid shell and liquid core, are an interesting class materials with numerous applications various methods synthesis. One common method for synthesis nanoparticles is flash nanoprecipitation. For multicomponent system (n-hexadecane) (polystyrene), we hypothesize that nanocapsules will form from droplets created by the turbulent mixing in nanoprecipitation process. We anticipate n-hexadecane molecules should phase-separate more rapidly non-solvent, thus becoming...
The third-order nonlinear optical properties of a hybrid polymer film containing substituted thiophene rings copolymerized with unsubstituted selenophene were measured using the Z-scan technique. Large, resonantly enhanced nonlinearities found at wavelengths on low-energy side absorption band. In contrast to results similar copolymer incorporating only thiophene, strong two-photon appeared in near infrared. imaginary part susceptibility can be adequately explained as saturation an exciton...
Fluorescence recovery after two-photon photobleaching (TP-FRAP) was used to characterize the diffusion in polymer thin films. Using a two-photon/confocal microscope, region bleached inside fluorophore-doped poly(vinyl alcohol) film. An ellipsoidal form of this spot observed, and simple derived for fluorescence at center, enabling local fluorophore coefficient be determined. A series films with varying amounts added plasticizer were measured determine relation between content coefficient. In...
An undergraduate level experiment is presented for demonstrating total internal reflection. The yields a relatively precise value of the refractive index prism to be found from measurement incident angle at which reflection occurs. Analytic expressions are obtained as function both equilateral and right prisms. Students can observe not only critical occurs, but measure analyze significant rise in reflected beam power. addition small fluid reservoir attached side enables determination liquid index.
Abstract Nanocrystals of anthracene were formed by "solvent shifting"—reducing the solute solubility changing ratio two components a binary solvent. Dispersions slowly‐growing nanoparticles with sizes ranging from 100 to 1000 nm prepared in an acetone/water A model growth was developed that described rapid initial increase particle size over several minutes, followed much slower hours days. Dynamic light scattering (DLS) measurements could be well using this model. UV–VIS and fluorescence...