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Multi-phased cesium lead iodide quantum dots with large stokes shift
摘要： Lead halide perovskite quantum dots (QDs) have emerged as one of the most promising candidates for lighting and biomedical applications. However, further applications are limited by energy transfer of F?rster resonance energy transfer (FRET) or photon reabsorption between different QDs due to QDs with small Stokes shifts. Here, we first report intrinsic cesium lead iodide QDs with large Stokes shifts from 262 to 289 nm with PL peaks in the range of 630 to 658 nm. We show that the large Stokes shift is attributed to the morphology of QDs with multiple phases. Our results in intrinsic lead iodide perovskite QDs with large Stokes shift may open new avenues in resolving energy transfer in biomedical and lighting applications.
关键词： Energy transfer,Perovskite quantum dots,Large Stokes shift,Luminescence,Nanocrystalline materials
更新于2025-09-23 15:19:57
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Cancer-Specific Biomarker hNQO1-Activatable Fluorescent Probe for Imaging Cancer Cells In Vitro and In Vivo
摘要： Human NAD(P)H quinone oxidoreductase-1 (hNQO1) is an important cancer-related biomarker, which shows significant overexpression in malignant cells. Developing an effective method for detecting NQO1 activity with high sensitivity and selectivity in tumors holds a great potential for cancer diagnosis, treatment, and management. In the present study, we report a new dicyanoisophorone (DCP) based fluorescent probe (NQ-DCP) capable of monitoring hNQO1 activity in vitro and in vivo in both ratiometric and turn-on model. NQ-DCP was prepared by conjugating dicyanoisophorone fluoroprobe with hNQO1 activatable quinone propionic acid (QPA), which remain non-fluorescent until activation by tumor-specific hNQO1. NQ-DCP featured a large Stokes shift (145 nm), excellent biocompatibility, cell permeability, and selectivity towards hNQO1 allowed to differentiate cancer cells from healthy cells. We have successfully employed NQ-DCP to monitor non-invasive endogenous hNQO1 activity in brain tumor cells in vitro and in xenografted tumors developed in nude mice.
关键词： NAD(P)H quinone oxidoreductase 1,cancer biomarker,tumor diagnosis,fluorescent probe,cancer imaging,large Stokes shift,dicyanoisophorone
更新于2025-09-19 17:15:36
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A large Stokes shift, sequential, colorimetric fluorescent probe for sensing Cu2+/S2- and its applications
摘要： Copper ions (Cu2+) and sulfide (S2?) are important markers in many physiologies and pathological processes. In this work, a new near-infrared fluorescent probe 1 for colorimetric and sequential detection of Cu2+/S2? was designed and developed. The probe showed a rapid (less than 1 min), highly selective and sensitive response toward copper ions. Notably, the probe could also be applied to detect S2? through reversible formation-separation of complex 1-Cu2+ and CuS with a large Stokes shift of 234 nm. The detection limit for Cu2+ and S2? was found to be 1.8 × 10-8 M and 1.5 × 10-8 M, respectively. Furthermore, the binding stoichiometry between 1 and Cu2+ was found to be 1:1, the binding mode was also demonstrated using density functional theory (DFT) calculations and contrastive compound research. In addition, the probe was successfully applied in real water samples assay for the detection of Cu2+, and the strip papers experiments also showed that probe 1 can be used to detect Cu2+ and S2?.
关键词： DFT calculations,Colorimetric,Near-infrared,Sulfide,Large Stokes shift,Copper ions
更新于2025-09-19 17:15:36
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A new turn-on fluorescent probe with ultra-large fluorescence enhancement for detection of hydrogen polysulfides based on dual quenching strategy
摘要： Based on dual quenching strategy (ESIPT inhibited quenching and PET quenching), we have developed a new turn-on fluorescent probe 1. Combining 3-(benzo[d]thiazol-2-yl)-10-butyl-10H-phenothiazin-2-ol (dye 2) as the fluorophore and 2-fluoro-5-nitro-benzoic as the recognition moiety, probe 1 had feature of notable large Stokes shift, highly sensitivity and selective for monitoring H2Sn with remarkable fluorescence enhancement (328-fold) response at 534 nm. Probe 1 exhibited excellent performance in the quantitative detection of H2Sn with a 137 nm Stokes shift and a low detection limit of 26 nM in solution. Finally, probe 1 was successfully utilized to image H2Sn in living A549 cells and zebrafish.
关键词： Large stokes shift,ESIPT,Hydrogen polysulfides,PET
更新于2025-09-19 17:15:36
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Microfibers Doped with Perovskite Nanocrystals for Ultralow-Loss Waveguides
摘要： Low loss optical waveguides have attracted intense interests as the building blocks for photonic devices and integrated circuits. Herein, we employed the all-inorganic halide perovskite nanocrystals (IHPNs) doped polymer microfibers for developing the active waveguides for the first time. We reveal that the absorption coefficient (2.6 cm-1) of the CsPbBr3 IHPNs-doped polymer fibers is one order of magnitude lower than that of traditional CdSe quantum dots (QDs)-based microfibers, which can be attributed to the much higher photoluminescence quantum yield of IHPNs. Moreover, manganese ions (Mn2+) were successfully inserted into CsPbX3 IHPNs to engineer the Stokes shift and eliminate the reabsorption effect. As a result, the Mn:CsPb(Br/Cl)3 IHPNs-doped polymer microfibers exhibited a record-low absorption coefficient of 0.33 cm-1. These findings reveal a great potential of perovskite nanocrystals in photonic technologies that also paves the way for solution-processed QDs in low-loss and long-range optical guiding.
关键词： Stokes shift,perovskite nanocrystals,polymer microfibers,Low-loss waveguides,ion doping
更新于2025-09-16 10:30:52
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Study on Solvent Effect and Estimation of Dipole Moments of Laser Dye 3ADHC
摘要： In this paper solvent effect of 3-acetyl-7-(diethylamino)-2H-chromen-2-one (3ADHC) dye molecule have been studied by solvatochromic shift method. The electronic absorption and emission spectra of the dye molecule were recorded in a variety of polar protic and polar aprotic solvents at room temperature (298K). Solvatochromic shifts, specifically bathochromic (red) shifts were observed in the absorption and emission spectra as a result of solvent polarity, it signifies the π→π* transition involved. The ground state dipole moment and excited state dipole moment of 3AHDC is calculated using solvent correlation methods. Obtained results are in good agreement with the ground state dipole moment calculated by Gaussion computational methods. The ground and excited state dipole moment of the 3ADHC have also been computed from ab initio calculations and compared with those determined experimentally. It has been found that excited-state dipole moment (μe) is greater than ground-state dipole moment (μg) for the title molecule. The increase in dipole moment in the excited singlet states ranges between 3.93 to 8.60D for 3ADHC. This demonstrates that test molecule is more polar in excited states than in ground states for all the solvents used. The spectral changes were analyzed by Kamlet-Taft parameters.
关键词： Stokes shift,Solvatochromic,Molecular Structure of 3-acetyl-7-(diethylamino)-2H-chromen-2-one (3ADHC),Ground state and excited state dipole moment
更新于2025-09-12 10:27:22
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Anomalous Stokes shift of colloidal quantum dots and their influence on solar cell performance
摘要： We report an anomalous Stokes shift effect observed in colloidal solutions containing down-shifting Carbon quantum dots (CQDs) of different sizes that is expected to have a positive in?uence on the power conversion ef?ciency of photovoltaic structures. Speci?cally, with an excitation wavelength of 390 nm, individual colloidal solutions of CQDs whose diameter was determined by the applied current during synthesis, exhibited photoluminescent (PL) emission wavelength peaks centered at 420 nm. However, the colloidal solution comprising the mixture of all the previously synthesized CQDs of different diameters was observed to have an anomalous PL Stokes shift centered at 515 nm. Furthermore, the afore-mentioned anomalous SSE was also observed in CdTe QDs when added to the CQD mixed-solution (CMS). Thus, whereas a mixture of CdTe QDs of different sizes, exhibited a down-shifted photoluminescence centered at 555 nm, the peak was observed to have an anomalous Stokes shift centered at 580 nm when combined with the CMS. Quantum dot characterization included crystal structure analysis as well as photon absorption and photoluminescence wavelengths. Subsequently, the synthesized QDs were dispersed in a polymeric layer of PMMA and incorporated on functional and previously characterized solar cells, to quantify their in?uence in the electrical performance of the photovoltaic devices. The observations indicate an improvement in the PCE of 4.6% when incorporating Carbon QDs, 2.9% with CdTe QDs and 4.8% when employing both C and CdTe QDs.
关键词： solar cell performance,photoluminescence,Carbon quantum dots,Anomalous Stokes shift,colloidal quantum dots,CdTe quantum dots,power conversion efficiency
更新于2025-09-11 14:15:04
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Precisely Encoded Barcodes Using Tetrapod CdSe/CdS Quantum Dots with a Large Stokes Shift for Multiplexed Detection
摘要： A serious obstacle to the construction of high-capacity optical barcodes in suspension array technology is energy transfer, which can prompt unpredictable barcode signals, limited barcode numbers, and the need for an unfeasible number of experimental iterations. This work reports an effective and simple way to eliminate energy transfer in multicolor quantum dots (QDs)-encoded microbeads by incorporating tetrapod CdSe/CdS QDs with a large Stokes shift (about 180 nm). Exploiting this unique feature enables the facile realization of a theoretical 7 × 7-1 barcoding matrix combining two colors and seven intensity levels. As such, microbeads containing tetrapod CdSe/CdS QDs are demonstrated to possess a powerful encoding capacity which allows for precise barcode design. The ability of the Shirasu porous glass membrane emulsification method to easily control microbead size facilitates the establishment of a 3D barcode library of 144 distinguishable barcodes, indicating the enormous potential to enable large-scale multiplexed detection. Moreover, when applied for the multiplexed detection of five common allergens, these barcodes exhibit superior detection performance (limit of detection: 0.01–0.02 IU mL?1) for both spiked and patient serum samples. Therefore, this new coding strategy helps to expand barcoding capacity while simultaneously reducing the technical and economic barriers to the optical encoding of microbeads for high-throughput multiplexed detection.
关键词： large Stokes shift,F?rster resonance energy transfer (FRET),photon re-absorption,quantum dots-encoded microbeads,multiplexed detection
更新于2025-09-11 14:15:04
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A multicolor large Stokes shift fluorogen-activating RNA aptamer with cationic chromophores
摘要： Large Stokes shift (LSS) fluorescent proteins (FPs) exploit excited state proton transfer pathways to enable fluorescence emission from the phenolate intermediate of 4-hydroxybenzylidene imidazolone (HBI) chromophore. An RNA aptamer named Chili mimics LSS FPs by inducing highly Stokes-shifted emission from several new green and red HBI analogs that are non-fluorescent when free in solution. The ligands are bound by the RNA in their protonated phenol form and feature a cationic aromatic side chain for increased RNA affinity and reduced magnesium dependence. In combination with oxidative functionalization at the C2 position of the imidazolone, this strategy yielded DMHBO+, which binds to the Chili aptamer with a low-nanomolar KD. Because of its highly red-shifted fluorescence emission at 592 nm, the Chili–DMHBO+ complex is an ideal fluorescence donor for F?rster resonance energy transfer (FRET) to the rhodamine dye Atto 590 and will therefore find applications in FRET-based analytical RNA systems.
关键词： RNA aptamer,fluorescence,fluorescence resonance energy transfer,fluorescent protein,large Stokes shift
更新于2025-09-10 09:29:36
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Highly sensitive fluorescent probe based on a novel phenothiazine dye for detection of thiophenols in real water samples and living cells
摘要： Based on an excited-state intramolecular proton transfer (ESIPT) fluorophore, a novel fluorescent off-on probe for detection of thiophenols was designed and synthesized. This probe (λex = 401 nm, λem = 527 nm) displayed high specificity for sensing thiophenols over other biologically related species. Besides, this probe possessed capabilities of monitoring thiophenols with rapid response rate (3 min), a large Stokes shift (126 nm), and high sensitivity (2.7 nM). The sensing mechanism was considered to be that thiophenols triggered thiolysis of the probe and the ESIPT fluorophore was released, as confirmed by means of HPLC and HRMS. Most notably, this probe was successfully applied to monitor levels of thiophenols in realistic samples and MDA-MB-231 cells.
关键词： Thiophenol,Large stokes shift,Probe,MDA-MB-231 cells
更新于2025-09-04 15:30:14