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Modulation of Ligands Conjugation for Efficient FAPbBr3 based Green Light-Emitting Diodes
摘要： Organic ligands capped on surface of perovskite nanocrystals (PeNCs) strongly influence the optical and electrical properties of the obtained PeNCs films, which are fundamental for efficient perovskite light-emitting diodes (PeLEDs). Here, we investigate the ligands effect through introduction of ligands with strong π conjugation, 1-(1-naphthyl)ethylamine bromide (NEABr), for the fabrication of FAPbBr3 PeNCs. Compared to the widely applied ligands of phenylethylamine bromide (PEABr), NEABr molecules containing naphthalene ring possess more delocalized electrons and better conductivity, which is beneficial for charge injection and transportation between interfaces. By varying the ligands ratio, high quality three dimensional FAPbBr3 PeNCs films with photoluminescence quantum yields up to 80% are fabricated. Based on the optimized PeNCs films, electroluminescent (EL) devices achieve a maximum external quantum efficiency of 8.6%, which is about three times higher than that of EL devices based on PEABr. Importantly, through understanding into the ligands effect, we demonstrate that the enhanced device efficiency is attributed to lower defect densities and decreased interfacial resistance in NEABr derived EL devices. Our findings about ligands conjugation on device performance may benefit other perovskites based optoelectronic devices.
关键词： ligands conjugation,perovskite nanocrystals,light-emitting diodes,charge injection,FAPbBr3
更新于2025-09-16 10:30:52
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The effect of molecular structure on the properties of quinoxaline-based molecules for OLED applications
摘要： Different donor-acceptor-donor (D-A-D) and donor-π-bridge-acceptor-π-bridge-donor (D-π-A-π-D) systems based on quinoxaline acceptor are compared. A significant difference in electrochemical and photophysical properties was found depending on molecular structure. A luminescence shift from 539 nm up to 671 nm was observed upon extension of conjugation length. The studied compounds were tested in fluorescent organic light emitting diodes (OLEDs) demonstrating an external quantum efficiency up to 4.5 % for the deep red non-doped device and 7% for the doped into the exciplex host device. A quantum-chemical interpretation of the electroluminescence spectra for the fabricated OLEDs was carried out including modelling of excimers and exciplexes.
关键词： OLEDs,conjugation length,Quinoxaline,donor-acceptor,organic emitter,exciplex
更新于2025-09-12 10:27:22
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Template-controlled on-surface synthesis of a lanthanide supernaphthalocyanine and its open-chain polycyanine counterpart
摘要： Phthalocyanines possess unique optical and electronic properties and thus are widely used in (opto)electronic devices, coatings, photodynamic therapy, etc. Extension of their π-electron systems could produce molecular materials with red-shifted absorption for a broader range of applications. However, access to expanded phthalocyanine analogues with more than four isoindoline units is challenging due to the limited synthetic possibilities. Here, we report the controlled on-surface synthesis of a gadolinium-supernaphthalocyanine macrocycle and its open-chain counterpart poly(benzodiiminoisoindoline) on a silver surface from a naphthalene dicarbonitrile precursor. Their formation is controlled by the on-surface high-dilution principle and steered by different metal templates, i.e., gadolinium atoms and the bare silver surface, which also act as oligomerization catalysts. By using scanning tunneling microscopy, photoemission spectroscopy, and density functional theory calculations, the chemical structures along with the mechanical and electronic properties of these phthalocyanine analogues with extended π-conjugation are investigated in detail.
关键词： π-conjugation,Phthalocyanines,on-surface synthesis,gadolinium-supernaphthalocyanine,poly(benzodiiminoisoindoline)
更新于2025-09-12 10:27:22
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Nd <sup>3+</sup> :YAG laser based on the <sup>4</sup> F <sub/>3/2</sub> → <sup>4</sup> I <sub/>13/2</sub> secondary transition with a phase-conjugate electro-optically Q-switched open multiloop cavity
摘要： Lasing on the 4F3/2 → 4I13/2 secondary transition (λ = 1.34 μm) in a Nd3+ : YAG laser with phase conjugation by four-wave mixing directly in the active laser medium was experimentally studied in the regime of electro-optic Q-switching of an open multiloop cavity. The use of an electro-optic Q-switch with a controllable delay of its opening made it possible to increase the amplitude and temporal stabilities of the output laser parameters. The maximum laser pulse energy was 100 mJ at a pulse duration of 120 ns. The phase-conjugate radiation divergence was 0.8 mrad at beam quality Mx2 = My2 = 1.3. Nonlinear optical conversion of 1.34 μm laser radiation to visible radiation was achieved experimentally. Second and third harmonic generation at wavelengths of 0.67 and 0.446 μm with conversion efficiencies of 25 % and 8 %, respectively, was demonstrated.
关键词： phase conjugation,secondary transition,stability of laser parameters,Nd3+ : YAG laser,electro-optic Q-switching
更新于2025-09-12 10:27:22
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[Methods in Molecular Biology] || Multifunctional Magnetic Nanoparticles-Labeled Mesenchymal Stem Cells for Hyperthermia and Bioimaging Applications
摘要： Magnetic nanoparticles have demonstrated considerable capacity for theranosis purposes due to their unique characteristics, including magnetic properties, comparable size to biomolecules, favorable conjugations of drugs and biomolecules, ability to labeling, and capability of sensing, separation, detection, and targeted drug delivery. They could be exploited in magnetic resonance imaging as the contrast agents and also warmed as exposed to an external magnetic AC ?eld that could be applied in hyperthermia. Here, progresses and advances in the strategy and assembly of ?uorescent magnetic nanoparticles are presented for stem cell tracing and drugs/biomolecules targeting into cells.
关键词： Conjugation,Fluorescent probe,Stem cell tracing,Magnetic resonance imaging,Magnetic nanoparticles,Hyperthermia
更新于2025-09-12 10:27:22
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An Efficient DFG Induced Wavelength Exchanged-OPC Using Only Two Ti:PPLN Waveguides with Single Pump Configuration
摘要： An unconventional single pump configuration of Wavelength Exchanged Optical Phase Conjugation (WE-OPC) through Difference Frequency Generation (DFG) employing two identical Ti:PPLN waveguides having same grating period and a single pump source is theoretically analyzed and simulated resulting in higher conversion efficiency of OPC.WE-OPC has been found very effective in extenuating nonlinearity and inflating spectral efficiency in optical transmission systems. The proposed WE-OPC enabled WDM optical transmission system modeled as a wavelength converter has been simulated with 10 channels offering much higher conversion efficiencies of about 3.3 dB and 3.49 dB for higher frequency band to lower frequency band and vice versa respectively.
关键词： Fiber optics communications,Dispersion compensation devices,Fiber optics and optical communications,Optical Phase conjugation,Wavelength conversion devices
更新于2025-09-12 10:27:22
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Orientation-Controlled Bioconjugation of Antibodies to Silver Nanoparticles
摘要： Here we report on the use of heterobifunctional cross-linkers (HBCLs) to control the number, orientation, and activity of immunoglobulin G antibodies (Abs) conjugated to silver nanoparticles (AgNPs). A hydrazone conjugation method resulted in exclusive modification of the polysaccharide chains present on the fragment crystallizable region of the Abs, leaving the antigen-binding regions accessible. Two HBCLs, each having a hydrazide terminal group, were synthesized and tested for effectiveness. The two HBCLs differed in two respects, however: (1) either a thiol or a dithiolane group was used for attachment to the AgNP; and (2) the spacer arm was either a PEG chain or an alkyl chain. Both cross-linkers immobilized 5 ± 1 Abs on the surface of each 20-nm-diameter AgNP. Electrochemical results, obtained using a half-metalloimmunoassay, proved that Abs conjugated to AgNPs via either of the two HBCLs were 4 times more active than those conjugated by the more common physisorption technique. This finding confirmed that the HBCLs exerted orientational control over the Abs. We also demonstrated that the AgNP-HBCL-Ab conjugates were stable and active for at least 2 weeks. Finally, we found that the stability of the HBCLs themselves was related to the nature of their spacer arms. Specifically, the results showed that the HBCL having the alkyl chain is chemically stable for at least 90 days, making it the preferred cross-linker for bioassays.
关键词： alkyl chain,antigen-binding regions,heterobifunctional cross-linkers,PEG chain,hydrazone conjugation,physisorption technique,immunoglobulin G antibodies,silver nanoparticles,half-metalloimmunoassay,fragment crystallizable region
更新于2025-09-12 10:27:22
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Nonlinearity Compensation through Optical Phase Conjugation for Improved Transmission Reach/Rate
摘要： Optical phase conjugation is a well-known technique to provide dispersion and nonlinearity compensation directly in the optical domain. The link properties play an important role in the achievable improvements in transmission reach/rate. Here, we review our recent investigations on the impact of sub-optimum transmission links as well as our effort on the implementation of the optical phase conjugator itself looking beyond using highly nonlinear fibers as nonlinear medium and focusing on integrated silicon waveguides. Preliminary results on combining optical phase conjugation with digital techniques such as probabilistic shaping will also be discussed.
关键词： optical phase conjugation,nonlinearity compensation,four-wave mixing,optical communication
更新于2025-09-10 09:29:36
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Biocompatible Gold Nanorod Conjugates for Preclinical Biomedical Research
摘要： Gold nanorods with a peak absorption wavelength of 760 nm were prepared using a seed-mediated method. A novel protocol has been developed to replace hexadecyltrimethylammonium bromide on the surface of the nanorods with 16-mercaptohexadecanoic acid and metoxy-poly(ethylene glycol)-thiol, and the monoclonal antibody HER2. The physical chemistry properties of the conjugates were monitored through optical and zeta-potential measurements to confirm surface chemistry changes. The efficiency of the modifications was quantified through measurement of the average number of antibodies per gold nanorod. The conjugates were investigated for different cells lines: BT-474, MCF7, MCF10, MDCK, and fibroblast. The results show successful cell accumulation of the gold nanorod HER2 conjugates in cells with HER2 overexpression. Incubation of the complexes in heparinized mouse blood demonstrated the low aggregation of the metallic particles through stability of the spectral properties, as verified by UV/VIS spectrometry. Cytotoxicity analysis with LDH release and MTT assay confirms strong targeting and retention of functional activity of the antibody after their conjugation with gold nanorods. Silver staining confirms efficient specific binding to BT-474 cells even in cases where the nanorod complexes were incubated in heparinized mouse blood. This is confirmed through in vivo studies where, following intravenous injection of gold nanorod complexes, silver staining reveals noticeably higher rates of specific binding in mouse tumors than in healthy liver. The conjugates are reproducible, have strong molecular targeting capabilities, have long term stability in vivo and can be used in pre-clinical applications. The conjugates can also be used for molecular and optoacoustic imaging, quantitative sensing of biological substrates, and photothermal therapy.
关键词： Metallic nanoparticles,Gold nanorod fabrication,Cell particle targeting,Gold surface modification,Biocompatible targeting agent,Antibody conjugation
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Portland, OR, USA (2018.11.13-2018.11.14)] 2018 IEEE Avionics and Vehicle Fiber-Optics and Photonics Conference (AVFOP) - Analog Photonic Timing Equalization Method for Multi-Channel RF Photonic Links
摘要： A new photonic timing equalization approach is presented to compensate the group delay among multiple signals in an analog photonic link. The results show the group delay variation across multiple RF photonic channels can be significantly compensated with 96.2% reduction after the equalization.
关键词： Phase conjugation,Analog photonic link,Arrayed waveguide grating(AWG),Group delay
更新于2025-09-09 09:28:46