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One-pot synthesis of carbon dots co-doped with N and S: high quantum yield governed by molecular state and fluorescence detection of Ag <sup>+</sup>
摘要： Fluorescent carbon-based nanoparticles, called chronically as carbon dots (CDs), were synthesised from citric acid (CA) and 2-Aminothiophenol (2AT) via an N and S co-doped hydrothermal method. After a series of micro-structural characterisation, N and S elements could be sufficiently doped by means of the heteroatom in the CDs solution. The as-prepared CDs solution showed blue colour fluorescence with the highest QY of 78.6%, and study on the UV–visible and PL spectra further revealed that the outstanding fluorescence of as-prepared CDs mainly originates from the generated molecular fluorophores instead of the surface state. Owing to the strong fluorescence, the as-prepared CDs can be used as a sensing probe for the detection of Ag+ with high sensitivity and selectivity. However, the changes of fluorescence intensity exhibited the complex nature of the quenching mechanism due to the –SH and –NH2 groups on the fringes of carbonaceous cores or molecular fluorophores to aggregate into another fluorescent cores with the assistance of Ag+ ions, which promises a new approach for efficient detection of Ag+ for the application in industrial pollutants.
关键词： Ag+,N-CDs,S,quenching mechanism,molecular fluorophores,higher QYs
更新于2025-09-19 17:15:36
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Critical Review—Recent Progress in NIR Fluorophores Emitting over 1000 nm for Bioimaging
摘要： During the last five years, significant advances have been made in the synthesis of near-infrared (NIR) fluorophores emitting over 1000 nm for non-invasive deep-tissue imaging. Nano-materials such as single-walled carbon nanotubes (SWCNTs), following Ag2S and PbS quantum dots (QDs) have been employed as the first-generation NIR fluorescent probes, by which superior capabilities of NIR fluorescence imaging at the wavelengths of 1000–1400 nm (second NIR window) have been demonstrated. Recently, from the viewpoint of biomedical applications, organic-dye based NIR fluorophores emitting beyond 1000 nm have been synthesized. In this short review, we focus on recent advances in nanomaterial and organic-dye based NIR fluorophores for intravital deep bioimaging in the second NIR window.
关键词： bioimaging,organic dyes,second NIR window,nanomaterials,NIR fluorophores
更新于2025-09-19 17:15:36
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Novel 9,9-dimethylfluorene-bridged D–π–A-type fluorophores with a hybridized local and charge-transfer excited state for deep-blue electroluminescence with CIE <sub/>y</sub> ～ 0.05
摘要： Deep-blue light emitting materials are of great significance in the fields of commercial full-color organic light-emitting diodes (OLEDs) and solid-state lighting. The hybridized local and charge-transfer excited state (HLCT) is a promising strategy to achieve deep-blue emission and high photoluminescence quantum yield. Based on HLCT, we designed and synthesized two novel donor–π–acceptor, 9,9-dimethylfluorene-bridged fluorophores (DFPBI & TFPBI) for efficient deep-blue OLED applications. Non-doped devices, with DFPBI and TFPBI as emitters, exhibit deep-blue emission with CIE coordinates of (0.154,0.042) and (0.152,0.054), accompanied by good EL performance with maximum external quantum efficiencies (EQEs) of 4.18% and 5.74%, respectively. In particular, the TFPBI-based non-doped device displays a slow efficiency roll-off at high luminance with an EQE of 5.50% and 4.80% at 100 cd m?2 and 1000 cd m?2, respectively. This work not only demonstrates the potential of these two fluorophores in deep-blue OLEDs, but also provides tactics for the design of deep-blue light emitting materials by using the 9,9-dimethylfluorene-bridged D–π–A architecture.
关键词： 9-dimethylfluorene,9,fluorophores,deep-blue emission,HLCT,OLEDs
更新于2025-09-19 17:15:36
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On the impact of competing intra- and intermolecular triplet-state quenching on photobleaching and photoswitching kinetics of organic fluorophores
摘要： While buffer cocktails remain the most commonly used method for photostabilization and photoswitching of fluorescent markers, intramolecular triplet-state quenchers emerge as an alternative strategy to impart fluorophores with 'self-healing' or even functional properties such as photoswitching. In this contribution, we evaluated combinations of both approaches and show that inter- and intramolecular triplet-state quenching processes compete with each other. We find that although the rate of triplet-state quenching is additive, the photostability is limited by the faster pathway. Often intramolecular processes dominate the photophysical situation for combinations of covalently-linked and solution-based photostabilizers and photoswitching agents. Furthermore we show that intramolecular photostabilizers can protect fluorophores from reversible off-switching events caused by solution-additives, which was previously misinterpreted as photobleaching. Our studies also provide practical guidance for usage of photostabilizer–dye conjugates for STORM-type super-resolution microscopy permitting the exploitation of their improved photophysics for increased spatio-temporal resolution. Finally, we provide evidence that the biochemical environment, e.g., proximity of aromatic amino-acids such as tryptophan, reduces the photostabilization efficiency of commonly used buffer cocktails. Not only have our results important implications for a deeper mechanistic understanding of self-healing dyes, but they will provide a general framework to select label positions for optimal and reproducible photostability or photoswitching kinetics in different biochemical environments.
关键词： photoswitching,intramolecular quenching,self-healing dyes,super-resolution microscopy,intermolecular quenching,photostabilization,fluorophores,triplet-state quenching,STORM
更新于2025-09-19 17:15:36
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Optimal LED Filtering for Fluorescence Microscopy
摘要： LED illumination systems for fluorescence microscopy offer a wealth of benefits in comparison to traditional mercury and metal halide lamps, including ease of use, improved stability, and enhanced control. To fully realize these benefits, it is important to ensure that optical filters are configured correctly, which often can be confusing. However, without the correct filter configuration, experimental conditions can be suboptimal, and results may therefore be inaccurate. This article looks at optical filter setup in more depth, explaining the purpose and benefits of optimal LED filtering.
关键词： fluorophores,LED light source,optical filters,illumination systems,fluorescence
更新于2025-09-19 17:13:59
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Post-decorated surface fluorophores enhance the photoluminescence of carbon quantum dots
摘要： Photoluminescence (PL) is the center property to deploy carbon quantum dots (CQDs) in diverse applications although their physicochemical origin is still debated. Herein, carboxylic-terminated CQDs were synthesized from citric acid (CA) and treated sequentially with ethylenediamine (EDA). Infrared, magnetic, X-ray photoelectron and UV–Vis spectroscopies indicated the formation of surface fluorophores by the EDA treatment. The post-decorated surface fluorophores accounted for a resolved UV absorption band at 346 nm, which originated from HOMO → LUMO transition in the fluorophores. The post-decorated fluorophores dominated the emission spectrum of CQDs when excited with wavelengths below 340 nm and enhanced the PL quantum yield of CQDs from 20.7% to 47.6%. The results pave new understanding on the optical properties of CQDs derived from CA and amines.
关键词： Photoluminescence enhancement,Surface fluorophores,Optical origins,Amine treatment,Carbon quantum dots
更新于2025-09-16 10:30:52
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Bipolar fluorophores based on intramolecular charge-transfer moieties of sulfone for nondoped deep blue solution-processed organic light-emitting diodes
摘要： Dipolar emitters exhibited excellent performance in organic light-emitting diode (OLED). However, these molecules had intramolecular charge-transfer (ICT) properties, which posed challenge to obtain deep blue emission. In this study, three fluorophores were designed by introducing carbazole and diphenylamine as electron donors and sulfone as electron acceptor due to their mild charge-accepting properties and twisted angles. These materials appeared almost in vertical angles of the dihedral configuration, and exhibited high thermal and electrochemical stability, suitable for solution-processed OLED. The solution-processed non-doped devices based on these three emitters were realized, where two emissions within the standard deep blue emission range were achieved with the Commission International e de l’Eclairage (CIE) coordinates of (0.16, 0.12) and (0.16, 0.15).
关键词： bipolar fluorophores,intramolecular charge-transfer,deep blue,single layer,organic light-emitting diodes
更新于2025-09-16 10:30:52
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MCM-SO3H catalyzed synthesis of environment-sensitive fluorophores incorporating pyrene moiety: Optimization, fluorescence emission and theoretical studies
摘要： Six new highly fluorescent 5-(aryl)-1-phenyl-3-(pyren-1yl)-2-pyrazolines were synthesized by reaction of various (E)-3-aryl-1-(pyren-1-yl)prop-2-en-1-ones with phenyl hydrazine in the presence of sulfonated mesoporous silica (MCM-SO3H) as efficient and eco-friendly acidic catalyst. The chemical structures of all synthesized compounds were illustrated on the basis of spectral data (IR, 1H NMR and 13C NMR). This was followed by photophysical properties-based absorption and emission studies of the target compounds in solutions of different solvent polarities. The microenvironment-sensitive fluorescent pyrazolines labeled with pyrene exhibited valuable fluorescence properties with emission in the range of 600–700 nm with a marked response to change in the environmental polarities. A significant and pronounced red shift was observed in the emission spectrum of 5-(aryl)-1-phenyl-3-(pyren-1yl)-2-pyrazolines Δλ ～ 50 nm compared to the absorption spectrum Δλ ～ 10 nm upon increasing the solvent polarity. This indicated the presence of higher dipole moment in the excited state than in the ground state and the transition involved are π-π* transition through the charge transfer phenomena. The fundamental understanding of solvatochromic properties were analyzed through Lippert-Mataga and Reichardts correlations in order to estimate the change in dipole moments (Δμ) which suggested the emissive state of designed fluorescent 2-pyrazoline derivatives is of strong ICT character.
关键词： Pyrene,Solvatochromic properties,Eco-friendly,2-Pyrazolines,Fluorophores,MCM-SO3H
更新于2025-09-10 09:29:36
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Applications of Molecular Spectroscopy to Current Research in the Chemical and Biological Sciences || Using Fluorescence Spectroscopy to Diagnose Breast Cancer
摘要： Optical spectroscopy methods have had considerable impact in the field of biomedical diagnostics, providing novel methods for the early or noninvasive diagnosis of various medical conditions. Among them, fluorescence spectroscopy has been the most widely explored mainly because fluorescence is highly sensitive to the biochemical makeup of tissues. It has been shown that tumors were easily detected on account of altered fluorescence properties with respect to fluorescence of ordinary tissue. Breast cancer is one of the most commonly diagnosed cancers among women in the world and also it is one of the leading causes of deaths from cancer for the female population. However, when detected in early stage, it is one of the most treatable forms of cancer. Therefore, fluorescence technologies could be highly beneficial in early detection and timely treatment of cancer. This chapter presents main results and conclusions that have been reported on the use of fluorescence spectroscopy for the investigation of breast cancer. It also gives an overview on the instruments and methodology of measurements, on the main endogenous fluorophores present in tissues, on the tissue fluorescence, and on the statistical methods that aid interpretations of fluorescence spectra. Finally, examples of using various fluorescence techniques, such as excitation, emission and synchronous spectroscopy, excitation-emission matrices, and lifetimes, for the breast cancer diagnosis are presented.
关键词： fluorescence,cancer diagnosis,breast cancer,fluorophores,tissue fluorescence
更新于2025-09-10 09:29:36
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Synthesis of Novel Organic-Inorganic Hybrid Fluorescent Microspheres and Their Applications as Fe(III), Hg(II) and Biothiols Probes
摘要： Organic-inorganic hybrid fluorescent microspheres (OI-FMs) without typical fluorophores were prepared. Fluorescence quantum yield of OI-FMs is up to 0.7 after being heated in an oven at 120°C (named as OIFMs-120). Interestingly, OI-FMs-120 shows different detection performances in different solvents. It can be used for qualitative and quantitative detection of Fe3+ with a detection limit of 37.8 nM in absolute ethanol. While in aqueous solution, it can be applied as an ONOFF-ON fluorescent probe. Fluorescence of the probe is quenched by Hg2+and later recovered by biothiols. The detection limit are as low as 34.9 nM for Hg2+, 91.0 nM for Cys, 0.12 μM for Hcy and 0.13 μM for GSH in aqueous medium, respectively.
关键词： Biothiols,Heavy metal ions,Atypical fluorophores,Fluorescence sensor
更新于2025-09-09 09:28:46