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Design and Synthesis of a Well-Controlled Mechanoluminescent Polymer System Based on Fluorescence Resonance Energy Transfer with Spiropyran as a Force-Activated Acceptor and Nitrobenzoxadiazole as a Fluorescent Donor
摘要： Colorimetric mechanophores, which change color through force-induced covalent bond breakage, have been incorporated into polymer chains to create mechanochromic materials. However, the color change of most mechanophores is a turn-on response. In this work, we designed and synthesized a novel mechanoluminescent polymer system, PBA-SP-P(MMA-co-NBD), based on fluorescence resonance energy transfer (FRET) with spiropyran (SP) as a force-activated "on/off" mechanophore acceptor and nitrobenzoxadiazole (NBD) as a fluorescent donor. It is a comb polymer having NBD-bearing poly(methyl methacrylate) (PMMA) side chains grafted onto a poly(butyl acrylate) (PBA) backbone through SP groups. The processed polymer yields a morphology having NBD-containing PMMA nanodomains embedded into a PBA matrix with SP at the interface. The distance between NBD and SP functionalities is less than 10 nm with confinement of the nanophase separation, which effectively facilitates their fluorescence resonance energy transfer. Under uniaxial stretch, the materials change color at strains as low as about 18% and undergo a green-to-red fluorescence color switch. The two colors are ratiometric, exhibiting a linear correlation with strain after the onset of mechanoactivation. The color change is greatly enhanced right after failure. The fluorescence emission performance can be well controlled through regulating the PMMA/PBA and SP/NBD ratios in the synthesis. The synthesized polymer system exhibits a good potential as an indicator in monitoring microscale cut damages.
关键词： mechanochromic materials,nitrobenzoxadiazole,spiropyran,fluorescence resonance energy transfer,mechanoluminescent polymer
更新于2025-09-16 10:30:52
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Nanococktail Based on AIEgens and Semiconducting Polymers: A Single Laser Excited Image-Guided Dual Photothermal Therapy
摘要： Semiconducting polymers (SPs)-based dual photothermal therapy (PTT) obtained better therapeutic effect than single PTT due to its higher photothermal conversion efficiency. However, most dual PTT need to use two lasers for heat generation, which brings about inconvenience and limitation to the experimental operations. Herein, we report the development of “nanococktail” nanomaterials (DTPR) with 808 nm-activated image-guided dual photothermal properties for optimized cancer therapy. Methods: In this work, we co-encapsulated AIEgens (TPA-BDTO, T) and SPs (PDPPP, P) by using maleimide terminated amphiphilic polymer (DSPE-PEG2000-Mal, D), then further conjugated the targeting ligands (RGD, R) through “click” reaction. Finally, such dual PTT nanococktail (termed as DTPR) was constructed. Results: Once DTPR upon irradiation with 808 nm laser, near-infrared fluorescence from T could be partially converted into thermal energy through fluorescence resonance energy transfer (FRET) between T and P, coupling with the original heat energy generated by the photothermal agent P itself, thus resulting in image-guided dual PTT. The photothermal conversion efficiency of DTPR reached 60.3% (dual PTT), much higher as compared to its inherent photothermal effect of only 31.5% (single PTT), which was further proved by the more severe photothermal ablation in vitro and in vivo upon 808 nm laser irradiation. Conclusion: Such smart “nanococktail” nanomaterials could be recognized as a promising photothermal nanotheranostics for image-guided cancer treatment.
关键词： semiconducting polymers,aggregation-induced emission fluorogens,fluorescence resonance energy transfer,A single laser,dual photothermal therapy
更新于2025-09-16 10:30:52
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Hybrid CdSe/CsPbI <sub/>3</sub> quantum dots for interface engineering in perovskite solar cells
摘要： Hybrid CdSe/CsPbI3 quantum dots (QDs) are selected for incorporation between the perovskite film and the hole transport layer (HTL). Owing to the high absorption coefficient and the suitable band gap of CsPbI3, an optimized energy level structure can be expected. Besides, energy transfer could be realized due to the overlap between the emission spectrum of CdSe QDs and the excitation spectrum of CsPbI3 QDs. Hence, CdSe/CsPbI3 QDs can serve as an interface layer to promote interfacial charge extraction and enhance light harvesting ability simultaneously. Compared with pristine perovskite solar cells (PSCs), hybrid CdSe/CsPbI3 QD incorporated PSCs achieve 21% enhancement in power conversion efficiency (PCE). The enhancement of PCE can be ascribed to the ultrafast charge carrier dynamics and F?rster resonance energy transfer (FRET) effect. The design of hybrid CdSe/CsPbI3 QDs offers an alternative method for interfacial engineering to enhance optical properties and facilitate the charge transport process in PSCs.
关键词： interface engineering,charge transport,perovskite solar cells,Hybrid CdSe/CsPbI3 quantum dots,F?rster resonance energy transfer
更新于2025-09-16 10:30:52
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F?rster Resonance Energy Transfer between Colloidal CuInS2/ZnS Quantum Dots and Dark Quenchers
摘要： F?rster resonance energy transfer (FRET) using colloidal semiconductor quantum dots (QDs) and dyes is of importance in a wide range of biological and biophysical studies. Here, we report a study on FRET between CuInS2/ZnS QDs and dark quencher dye molecules (IRDye QC-1). Oleate-capped QDs with photoluminescence quantum yields (PLQYs) of 55±4% are transferred into water by using two types of multifunctional polymer ligands combining imidazole groups and specific moieties with amine or methoxy groups as the terminal sites. The resulting water-dispersible QDs show PLQYs as high as 44±4% and exhibit long-term colloidal stability (at least 10 months at 4 °C in the dark) with a hydrodynamic diameter of less than 20 nm. A side-by-side comparison experiment was performed using the amine or methoxy-functionalized QDs for coupling to dark quencher dye molecules. The amine-functionalized QDs bind to the dye molecules via covalent bonds while methoxy-functionalized ones bind only weakly and non-specifically. The progressive quenching of the QD emission and shortening of its photoluminescence decay time upon increasing the number of conjugated dye molecules demonstrate that the QD acts as the energy donor and the dark quencher dye as the energy acceptor in a donor-acceptor FRET pair. The FRET dynamics of the QD-dye conjugates are simulated using two different models based on the possible origin of the multiexponential PL decay of the QDs (i.e., variations in nonradiative or radiative decay rates). The model based on the radiative decay rates provides a better fit of our experimental data and estimates a donor–acceptor distance (6.5 nm) that matches well the hydrodynamic radius of the amine-functionalized QDs.
关键词： dark quencher dye molecules,energy acceptor,multifunctional polymer ligands,CuInS2/ZnS,F?rster resonance energy transfer,colloidal semiconductor quantum dots,energy donor,photoluminescence quantum yields
更新于2025-09-12 10:27:22
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Understanding the nature of mean-field semiclassical light-matter dynamics: An investigation of energy transfer, electron-electron correlations, external driving, and long-time detailed balance
摘要： Semiclassical electrodynamics (with quantum matter plus classical electrodynamics fields) is an appealing approach for studying light-matter interactions, especially for realistic molecular systems. However, there is no unique semiclassical scheme. On the one hand, intermolecular interactions can be described instantaneously by static two-body interactions connecting two different molecules, while a classical transverse E field acts as a spectator at short distance; we will call this Hamiltonian no. I. On the other hand, intermolecular interactions can also be described as effects that are mediated exclusively through a classical one-body E field without any quantum effects at all (assuming we ignore electronic exchange); we will call this Hamiltonian no. II. Moreover, one can also mix these two different Hamiltonians into a third, hybrid Hamiltonian, which preserves quantum electron-electron correlations for lower excitations but describes higher excitations in a mean-field way. To investigate which semiclassical scheme is most reliable for practical use, here we study the real-time dynamics of a minimalistic many-site model—a pair of identical two-level systems (TLSs)—undergoing either resonance energy transfer (RET) or collectively driven dynamics. While both approaches (no. 1 and no. 2) perform reasonably well when there is no strong external excitation, we find that no single approach is perfect for all conditions (and all methods fail when a strong external field is applied). Each method has its own distinct problems: Hamiltonian no. I performs best for RET but behaves in a complicated manner for driven dynamics; Hamiltonian no. II is always stable, but obviously fails for RET at short distances. One key finding is that, for externally driven dynamics, a full configuration-interaction description of Hamiltonian no. I strongly overestimates the long-time electronic energy, highlighting the not obvious fact that, if one plans to merge quantum molecules with classical light, a full, exact treatment of electron-electron correlations can actually lead to worse results than a simple mean-field electronic structure treatment. Future work will need to investigate (i) how these algorithms behave in the context of more than a pair of TLSs and (ii) whether or not these algorithms can be improved in general by including crucial aspects of spontaneous emission.
关键词： resonance energy transfer,semiclassical electrodynamics,mean-field dynamics,light-matter interactions,electron-electron correlations
更新于2025-09-12 10:27:22
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A target analyte induced fluorescence band shift of piperazine modified carbon quantum dots: a specific visual detection method for oxytetracycline
摘要： Through the protection/deprotection of one amine group and the amidation reaction, piperazine was used to modify carbon quantum dots (CQDs) and successfully served as a medium to combine oxytetracyclines (OTC) in solution by hydrogen bonding and electrostatic interactions. Fluorescence resonance energy transfer (FRET) probably occurred between piperazine modified CQDs (P-CQDs) and combined OTC, which resulted in the red-shift of the fluorescence band. Besides superior specificity for examining, a good linear relationship between the maximum emission wavelength of P-CQDs and concentrations of OTC (0 to 10 lM) can be obtained, which provides a rapid and convenient visual fluorescence detection method of OTC.
关键词： carbon quantum dots,oxytetracycline,visual detection,fluorescence resonance energy transfer,piperazine
更新于2025-09-12 10:27:22
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High efficiency dye-sensitized solar cells with <i>V</i> <sub/>OC</sub> – <i>J</i> <sub/>SC</sub> trade off eradication by interfacial engineering of the photoanode|electrolyte interface
摘要： Interfacial modification of the photoanode|electrolyte interface using oleic acid (OA) is thoroughly investigated in this present study. The overall photoconversion efficiency of 11.8% was achieved under the illumination of 100 mW cm?2 with an optical filter of AM 1.5 G. OA molecules were meant to be adsorbed on to the vacant areas of the TiO2 and the OA moieties leached out the aggregated C106 dye molecules from the TiO2 surface. There was a strong spectral overlap between the absorption spectrum of donor (OA) and the emission spectrum of acceptor (C106), leading to effective F?rster Resonance Energy Transfer (FRET) between OA and C106 and suggested an excellent opportunity to improve the photovoltaic performances of DSSCs. UV-vis DRS and UPS analysis revealed that OA molecules created new surface (mid-gap energy) states (SS) in TiO2 and these SS played a major role in the electron transport kinetics. Mott–Schottky analysis of DSSCs under dark conditions was carried out to find the shift in the flat band potential of TiO2 upon OA modification. Surprisingly, no trade off between VOC and JSC was observed after interfacial modification with OA. The dynamics of charge recombination and electron transport at the photoanode|electrolyte interface were studied in detail using electrochemical impedance spectroscopy.
关键词： interfacial engineering,F?rster Resonance Energy Transfer,oleic acid,photoconversion efficiency,dye-sensitized solar cells
更新于2025-09-12 10:27:22
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Aqueous Carbon Quantum Dot-Embedded PC60-PC <sub/>61</sub> BM Nanospheres for Ecological Fluorescent Printing: Contrasting Fluorescence Resonance Energy-Transfer Signals between Watermelon-like and Random Morphologies
摘要： To go beyond the PC60 surfactant structure, the double-layer micelle morphology in water motivates exploration of altered protocols to produce new morphologies. Furthermore, the low photoluminescence quantum yield of aqueous fullerene-based particles encourages high fluorescence to create a light-emitting display. With this in mind, we established new hybrid n-type nanospheres with carbon quantum dot (CQD)-embedded PC60-PC61BM particles, processed using two different protocols. The homogenizer-assisted PC60-CQD-PC61BM resulted in a watermelon-shaped spherical particle, whereas a circular morphology with randomly embedded CQDs was observed in the microwave-treated hybrids. More surprisingly, the watermelon-shaped colloid induced efficient fluorescence resonance energy transfer (FRET) between the CQD and C60 molecules of PC61BM, and the FRET-mediated emission signature diminished gradually as the stripe patterns collapsed. This phenomenon allowed different fluorescent colors in the colloidal printing film. We thereby provided the new carrier dynamics of the particle photonic activities of the developed aqueous PC60-based colloids with the possibility of ecological utilization.
关键词： water-processable organic semiconductor colloids,fullerene-based nanoparticles,fluorescence resonance energy transfer,ecological fluorescent printing,carbon quantum dots
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Toward Coupling Color Centers in Single Crystal Diamond to Two-Dimensional Materials
摘要： Individual nitrogen vacancy (NV) color centers in diamond are bright, photo-stable, atomic-sized dipole emitters [1]. Consequently, they represent optimal candidates for novel scanning near field microscopy techniques [2]. Here, NV centers form one member of a F¨orster Resonance Energy Transfer (FRET) pair. Due to their broadband emission (> 100 nm), NVs are versatile donors for FRET to systems absorbing in the near infrared spectral range. Highly-promising applications include, e.g., nanoscale imaging of fluorescent molecules or nanomaterials like graphene [2]. Critical parameters for FRET are the NV’s quantum efficiency, charge state stability and NV-sample-distance. Previous experiments used NVs in nanodiamond for FRET [2], however these NVs might suffer from quenching, instability and badly controlled surface termination. We here address this issue by using shallowly implanted NV centers in optimized cylindrical nanostructures [3] used as scanning probes in our homebuilt combination of a confocal and an atomic force microscope. In recent years, two-dimensional materials especially monolayers of semiconducting materials are of major interest in research. Particularly, dichalcogenides like, e.g., tungsten diselenide (WSe2) are promising candidates for a varity of applications [4]. WSe2 emits photons at a wavelength of around 750 nm while absorbing photons below 700 nm [4] which renders WSe2 as a promising FRET partner for NV centers. Here, we present first results towards demonstrating the interaction of NV color centers in single crystal diamond with WSe2. We envisage using quenching of the NV center sued as a donor in FRET in close proximity to the 2D material as a valuable sensing ressource.
关键词： F¨orster Resonance Energy Transfer (FRET),tungsten diselenide (WSe2),nitrogen vacancy (NV) color centers,diamond,two-dimensional materials
更新于2025-09-11 14:15:04
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A multiplexed FRET aptasensor for simultaneous detection of mycotoxins with magnetically controlled graphene oxide/Fe3O4 as single energy acceptor?
摘要： Aflatoxin B1 (AFB1) and fumonisin B1 (FB1) are the most common mycotoxins and often coexist in agricultural products, which are known to be a toxic superposition and even carcinogenic effects on humans. We proposed a multiplexed fluorescence resonance energy transfer (FRET) aptasensor for simultaneous detection of mycotoxins with magnetically controlled graphene oxide (GO)/Fe3O4 as single energy acceptor. CdTe quantum dots emitting green (GQDs) and red (RQDs) fluorescence are modified by aptamers specifically for AFB1 and FB1 and used as dual energy donors. Compared with conventional FRET system based on GO quencher, GO/Fe3O4, a single energy acceptor, can not only quench the fluorescence of aptamer-modified GQDs and RQDs with different emission peaks simultaneously, but also be removed by effective magnetic separation to eliminate the interference of background. In the absence of GO/Fe3O4 nanocomposites, the aptamer modified GQDs and RQDs give off strong fluorescence under ultraviolet radiation. The fluorescence of GQDs and RQDs is quenched when GO/Fe3O4 nanocomposites is added to the system owing to the π–π stacking interaction between GO/Fe3O4 nanocomposites and GQDs- and RQDs-labeled aptamer. However, in the presence of AFB1 and FB1, the binding of aptamers to their specific targets will fold their single stranded structures and hinder the contact between base group in aptamers and GO/Fe3O4, which cause the fluorescence recovery of GQDs and RQDs. With the help of one step of magnetic separation, the supernatants can be collected for fluorescence analysis. After optimization of detection conditions, the developed method had a wider linear range of 10 pg mL?1–100 ng mL?1 for AFB1 and 50 pg mL?1–300 ng mL?1 for FB1 and showed no cross-reactivity with other closely related mycotoxins, respectively. The limit of detection for AFB1 and FB1 are calculated to be 6.7 and 16.2 pg mL?1 based on S/N=3. The detection of mycotoxins has been successfully realized in peanut samples and a new application field of FRET system is expected for various targets.
关键词： aptasensor,fluorescence resonance energy transfer,aflatoxin B1,fumonisin B1,simultaneous detection
更新于2025-09-11 14:15:04