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Microcavity Nonlinear Optics with an Organically Functionalized Surface
摘要： We report enhanced optical nonlinear effects at the surface of an ultrahigh-Q silica microcavity functionalized by a thin layer of organic molecules. The maximal conversion efficiency of third harmonic generation reaches ～1680%=W2 and an absolute efficiency of 0.0144% at pump power of ～2.90 mW, which is approximately 4 orders of magnitude higher than that in a reported silica microcavity. Further analysis clarifies the elusive dependence of the third harmonic signal on the pump power in previous literature. Molecule-functionalized microcavities may find promising applications in high-efficiency broadband optical frequency conversion and offer potential in sensitive surface analysis.
关键词： Nonlinear Optics,Microcavity,Third Harmonic Generation,Surface Functionalization,Organic Molecules
更新于2025-09-23 15:19:57
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Inorganic Functionalization of CdSe <sub/><i>x</i> </sub> S <sub/> 1a?? <i>x</i> </sub> /ZnS Corea??Shell Quantum Dots and Their Photoelectric Properties
摘要： In this paper, different CdSexS1-x quantum dots (QDs) with stearic acid as ligands were synthesized, and then the outer ZnS shell was coated with oleylamine (OLA) as ligands using a single molecular source method. The surface ligand exchange of CdSe0.6S0.4 and CdSe0.6S0.4/ZnS quantum dots was carried out with ammonium zinc chloride ((NH4)2ZnCl4) inorganic ligands. The morphology, crystal form, and group of QDs were examined using a high-resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and fourier transform infrared spectroscopy (FTIR). Under the condition of simulated sunlight irradiation, the photoelectrochemical properties were tested with an electrochemical workstation. The results showed that the distance between QDs decreased after ligand exchange. The photocurrent density of CdSe0.6S0.4/ZnS QDs films after ligand exchange can reach 7.23 mA?cm-2, which is 11 times that of the photocurrent density before ligand exchange. The reason may be that ZnCl42- has strong ligand electron donor capacity, which increases the probability of non-radiative transition.
关键词： Inorganic functionalization,(NH4)2ZnCl4,CdSexS1-x/ZnS quantum dots
更新于2025-09-23 15:19:57
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Encapsulation of Dual Emitting Giant Quantum Dots in Silica Nanoparticles for Optical Ratiometric Temperature Nanosensors
摘要： Accurate temperature measurements with a high spatial resolution for application in the biomedical fields demand novel nanosized thermometers with new advanced properties. Here, a water dispersible ratiometric temperature sensor is fabricated by encapsulating in silica nanoparticles, organic capped PbS@CdS@CdS “giant” quantum dots (GQDs), characterized by dual emission in the visible and near infrared spectral range, already assessed as efficient fluorescent nanothermometers. The chemical stability, easy surface functionalization, limited toxicity and transparency of the silica coating represent advantageous features for the realization of a nanoscale heterostructure suitable for temperature sensing. However, the strong dependence of the optical properties on the morphology of the final core–shell nanoparticle requires an accurate control of the encapsulation process. We carried out a systematic investigation of the synthetic conditions to achieve, by the microemulsion method, uniform and single core silica coated GQD (GQD@SiO2) nanoparticles and subsequently recorded temperature-dependent fluorescent spectra in the 281-313 K temperature range, suited for biological systems. The ratiometric response—the ratio between the two integrated PbS and CdS emission bands—is found to monotonically decrease with the temperature, showing a sensitivity comparable to bare GQDs, and thus confirming the effectiveness of the functionalization strategy and the potential of GQD@SiO2 in future biomedical applications.
关键词： silica shell,QD functionalization,nanothermometers,optical sensor,ratiometric sensing
更新于2025-09-23 15:19:57
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How quantum dots aggregation enhances F??rster??Resonant Energy Transfer
摘要： As luminescent quantum dots (QDs) are known to aggregate themselves through their chemical activation by carbodiimide chemistry and their functionalization with biotin molecules, we investigate both effects on the fluorescence properties of CdTe QDs and their impact on F?rster Resonant Energy Transfer (FRET) occurring with fluorescent streptavidin molecules (FA). First, the QDs fluorescence spectrum undergoes significant changes during the activation step which are explained thanks to an original analytical model based on QDs intra-aggregate screening and inter-QDs FRET. We also highlight the strong influence of biotin in solution on FRET efficiency, and define the experimental conditions maximizing the FRET. Finally, a free-QD-based system and an aggregated-QD-based system are studied in order to compare their detection threshold. The results show a minimum concentration limit of 80 nM in FA for the former while it is equal to 5 nM for the latter, favouring monitored aggregation in the design of QDs-based biosensors.
关键词： fluorescence spectroscopy,biosensors,FRET,quantum dots,Biochemical functionalization
更新于2025-09-23 15:19:57
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Synthesis of a side-chain hole transporting polymer through Mitsunobu post-functionalization for efficient inverted perovskite solar cells
摘要： An efficient post-functionalization protocol of Mitsunobu reaction between a commercial reactive polymer of poly(4-vinylphenol) (PVP) and 9-(2-hydroxylethyl)-N,N,N,N-tetrakis(4-methoxyphenyl)-9H-carbazole-2,7-diamine) is reported to synthesize a novel side-chain polymer (PVP-CZ) with high density of hole transporting moieties. The polymer PVP-CZ exhibits adequate solvent resistance and excellent film forming ability for the fabrication of inverted perovskite solar cells (PVSCs). The thermal, optical and electrochemical properties of PVP-CZ were investigated in details. The steady-state photoluminescence (PL) and time resolved photoluminescence (TRPL) decay showed excellent hole-extracting ability of dopant-free PVP-CZ from the perovskite layer. As a result, the inverted PVSCs delivered a respectable power conversion efficiency of 17.75% with a high fill factor of 81.07%. These results indicate that synthetic strategy using the post-functionalization of Mitsunobu reaction is a promising protocol to develop novel side-chain hole transporting polymers for highly efficient PVSCs.
关键词： hole transporting material,Mitsunobu reaction,post-functionalization,side-chain polymer,perovskite solar cells
更新于2025-09-23 15:19:57
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Plasmonic biosensors fabricated by galvanic displacement reactions for monitoring biomolecular interactions in real time
摘要： Optical sensors are prepared by reduction of gold ions using freshly etched hydride-terminated porous silicon, and their ability to specifically detect binding between protein A/rabbit IgG and asialofetuin/Erythrina cristagalli lectin is studied. The fabrication process is simple, fast, and reproducible, and does not require complicated lab equipment. The resulting nanostructured gold layer on silicon shows an optical response in the visible range based on the excitation of localized surface plasmon resonance. Variations in the refractive index of the surrounding medium result in a color change of the sensor which can be observed by the naked eye. By monitoring the spectral position of the localized surface plasmon resonance using reflectance spectroscopy, a bulk sensitivity of 296 nm ± 3 nm/RIU is determined. Furthermore, selectivity to target analytes is conferred to the sensor through functionalization of its surface with appropriate capture probes. For this purpose, biomolecules are deposited either by physical adsorption or by covalent coupling. Both strategies are successfully tested, i.e., the optical response of the sensor is dependent on the concentration of respective target analyte in the solution facilitating the determination of equilibrium dissociation constants for protein A/rabbit IgG as well as asialofetuin/Erythrina cristagalli lectin which are in accordance with reported values in literature. These results demonstrate the potential of the developed optical sensor for cost-efficient biosensor applications.
关键词： Surface functionalization,Optical sensor,Lectin,Localized surface plasmon resonance,Biomolecular interactions,Gold nanostructure
更新于2025-09-23 15:19:57
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Compact, a??Clickablea?? Quantum Dots Photoligated with Multifunctional Zwitterionic Polymers for Immunofluorescence and In-Vivo Imaging
摘要： We detail the preparation of highly fluorescent quantum dots (QDs), surface-engineered with multifunctional polymer ligands that are compact, readily compatible with strain-promoted click conjugation, and the use of these nanocrystals in immunofluorescence and in-vivo imaging. The ligand design combines the benefits of mixed coordination (i.e., thiol and imidazole) with molecular-scale zwitterion motifs, yielding sterically-stabilized and compact QDs that present a controllable number of azide groups, for easy conjugation to biomolecules via the efficient and selective click chemistry. The polymer coating was characterized using NMR spectroscopy to extract estimates of the diffusion coefficient, hydrodynamic size and ligand density. The azide-functionalized QDs were conjugated to anti-tropomyosin receptor kinase B antibody (α-TrkB), or to the brain-derived neurotrophic factor (BDNF). These conjugates were highly effective for labeling the tropomyosin receptor kinase B (TrkB) in pyramidal neurons within cortical tissue and for monitoring the BDNF induced activation of TrkB signaling in live neuronal cells. Finally, the polymer-coated QDs were applied for in vivo imaging of Drosophila Melanogaster embryo, where the QDs remain highly fluorescent and colloidally stable, with no measurable cytotoxicity. These materials would be of great use in various imaging applications, where small size, ease of conjugation and great colloidal stability for in vivo studies are needed.
关键词： click chemistry,BDNF/TrkB,polymers,surface functionalization,embryo imaging,quantum dots
更新于2025-09-23 15:19:57
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Rhodium-Catalyzed C–H Functionalization of Silicon-Substituted Alkanes
摘要： Harnessing the β-Silicon Effect for Regioselective and Stereoselective Rhodium(II)-Catalyzed C–H Functionalization by Donor/Acceptor Carbenes Derived from 1-Sulfonyl-1,2,3-triazoles
关键词： alkylsilanes,rhodium catalysis,sulfonyltriazoles,C–H functionalization
更新于2025-09-19 17:15:36
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Diversity-Oriented Synthesis and Optical Properties of Bichromophoric Pyrrole-Fluorophore Conjugates
摘要： The mild reaction conditions of the palladium-copper coupling-isomerization reaction open a highly convergent, chromogenic route to blue emissive pyrroles in the sense of a consecutive four-component reaction. By virtue of this strategy a phenol derivative can be readily accessed, which can be transformed in a level-2 transformation to a library of bichromophoric pyrrol-fluorophore conjugates by facile alkylation with fluorophore halides. The photophysics of the underlying blue emitter derivative and the conjugates is studied by absorption and emission spectroscopy, furnishing intramolecular energy transfer at short distances as well as competing fluorescence quenching. In some cases partial energy transfer results in the occurrence of dual emission, for instance seen as magenta-rose emission arising from blue and red orange luminescence. The experimental photophysical studies are rationalized by DFT and TD-DFT calculations.
关键词： DFT,multicomponent reaction,energy transfer,level-2 functionalization,absorption,emission,bichromophores,pyrrole
更新于2025-09-19 17:15:36
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Micro/Nanomachines: from Functionalization to Sensing and Removal
摘要： Micro/nanomachines have attracted tremendous interest in chemo/bioanalytical science and environmental remediation due to the synergistic effect of unique motion characteristics and the inherited physicochemical properties from micro/nanomaterials. Past decade has witnessed great progresses on a wide array of micro/nanomachines with diverse functionalities for specific sensing and removal applications. The development of designed materials and structures, the exploration of new propulsion mechanism, and the realization of versatile functionalization are employed for potential applications. In this review, the recent advances in the exploration of functionalized micro/nanomachines are summarized, with special emphasis on the functionalization of micro/nanomachines and their corresponding sensing and removal capability. Possible challenges facing micro/nanomachines in sensing and removal application are discussed, accompanied with the extrapolated perspectives for the future focus.
关键词： micro/nanomachines,functionalization,removal,sensing
更新于2025-09-19 17:15:36