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Accidental contamination of substrates and polymer films by organic quantum emitters
摘要： We report the observation of ubiquitous contamination of dielectric substrates and polymethylmethacrylate matrices by organic molecules with optical activity in the visible spectral range. Contamination sites of individual solvent-related fluorophores in thin films of polymethylmethacrylate constitute fluorescence hotspots with quantum emission statistics and quantum yields approaching 30% at cryogenic temperatures. Our findings not only resolve prevalent puzzles in the assignment of spectral features to various nanoemitters on bare dielectric substrates or in polymer matrices, they also identify means for simple and cost-efficient realization of single-photon sources in the visible spectral range.
关键词： contamination of substrate and polymer matrix,organic fluorophores,single photon emitters,single molecule spectroscopy,Photoluminescence and fluorescence spectroscopy
更新于2025-11-25 10:30:42
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Glutaraldehyde non-conjugated chitosan polymer fluorophores for selective determination of picric acid via fluorescence resonance energy transfer strategy
摘要： Water-dispersed glutaraldehyde (GA) non-conjugated chitosan polymer fluorophores (GCPF) with quantum yield of 16 % is synthesized by stirring chitosan and GA for 6 h at room temperature in the present work. It is a facile and mild method and fluorescent GCPF can be stabled for two months. Owing to the spectral overlap of fluorescent spectrum of GCPF and absorption spectrum of picric acid (PA), a novel sensitive fluorescent method using fluorescent GCPF for PA detection from 10 nM to 50 μM via fluorescence resonance energy transfer (FRET) strategy is established. The distance between donor of GCPF and acceptor of PA (R0 value) is calculated to be 3.5 nm. FRET method using fluorescent GCPF possesses high sensitivity (LOD of 2.8 nM), and selectivity and fast response within 2 min. Moreover, fluorescent GCPF is also utilized in visual analysis of PA using cotton swabs. Fluorescence quenching effect can be observed by eyes irradiated with 365 nm ultraviolet light at cotton swabs and using GCPF solid on quartz glasses, which paves an effect and wide way for the application of fluorescent GCPF in our daily life.
关键词： Glutaraldehyde non-conjugated chitosan polymer fluorophores (GCPF),picric acid (PA),fluorescence resonance energy transfer (FRET),glutaraldehyde (GA),chitosan
更新于2025-11-14 15:23:50
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A promising family of fluorescent water-soluble aza-BODIPY dyes for in vivo molecular imaging
摘要： A new family of water-soluble and bioconjugatable aza-BODIPY fluorophores was designed and synthesized using a boron-functionalization strategy. These dissymmetric bis-ammonium aza-BODIPY dyes present optimal properties for a fluorescent probe, i.e. they are highly water-soluble, very stable in physiological medium, they do not aggregate in PBS, possess high quantum yield and finally they can be easily bioconjugated to antibodies. Preliminary in vitro and in vivo studies were performed for one of these fluorophores to image PD-L1 (Programmed Death-Ligand 1), highlighting the high potential of these new probes for future in vivo optical imaging studies.
关键词： molecular Imaging,Fluorescent probes,boron functionalization,aza-BODIPY,Water-soluble fluorophores
更新于2025-09-23 15:23:52
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Influence of molecular fluorophores on the research field of chemically synthesized carbon dots
摘要： Carbon dots (CDs) – small crystalline or amorphous carbon-based nanoparticles – have attracted much attention as promising fluorescent materials for a wide range of applications. One of their widely accepted advantages is the simplicity of the formation of highly luminescent CDs from a wide variety of organic precursors. At the same time, several recent studies on these chemically synthesized CDs raised questions about the nature of the resulting products. Their strong fluorescence can arise due to the presence of molecular organic fluorophores, not necessary CDs, as was assumed in the earlier publications. In this review, we consider fundamental characteristics of CDs and discuss several issues that currently prevent a better understanding of their structure-property correlation. Analysis of recent related studies identifying the presence of organic fluorophores in CDs with an emphasis on the optical properties of the synthesis products shows that their emission characteristics may be a complex interplay of stand-alone molecular fluorophores and their aggregates, possibly embedded in an amorphous carbon/polymer network. The review concludes with an outlook towards the challenges in the field of the bottom-up synthesized CDs, and their proper identification within the variety of the organic side-products eventually formed during the synthesis.
关键词： Luminescence,Chemical synthesis,Carbon dots,Optical properties,Molecular fluorophores,Aggregation
更新于2025-09-23 15:21:21
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Brain imaging with near-infrared fluorophores
摘要： As the centralized control system of the body, the brain is a complex organ of the utmost importance that even the most minor disorder and trauma can cause inestimable harm. There has always been an unmet clinical need for non-invasive high-resolution imaging techniques without a craniotomy to assist neurosurgeons gain anatomical and functional information for brain examination. Compared to the traditional methods, near-infrared (NIR) imaging (window I, 700–900 nm; window II, 1000–1700 nm) provides an innovative strategy for non-radioactive inspection with high tempo-spatial resolution. In particular, NIR-II imaging shows longer tissue penetration depths and ultralow tissue backgrounds due to drastically decreased photon scattering and tissue autofluorescence. In the current review, we highlight recent advances in NIR fluorophores, especially their rational design and application in NIR fluorescence imaging of the brain, sorted through brain tumors, traumatic brain injuries and bleeding diseases, as well as neurodegenerative disorders like Alzheimer’s and Huntington’s diseases. This state-of-the-art, non-invasive and non-radioactive optical imaging modality shows a promising prospect in understanding the fundamental pathophysiology of neurological diseases and is envisioned for potential clinical translation.
关键词： Fluorophores,Brain imaging,Near-infrared
更新于2025-09-23 15:21:01
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Early-stage identification of encapsulants photobleaching and discoloration in crystalline silicon photovoltaic module laminates
摘要： Commercially different variants of ethylene-vinyl acetate (EVA) encapsulants are available in the photovoltaic (PV) market. Photobleaching and discoloration are the two most commonly observed phenomena, and their initiation may be different for different encapsulants. To investigate the EVA encapsulant photobleaching and discoloration, solar cell laminates having different EVA films (UV-transparent [T], UV-cut [C], and combination of the two [TC]) were tested in Xenon test chamber. High temperatures are created in the laminates during the aging tests by using a thick insulation layer behind the backsheet. The UV fluorescence images and grayscale profile show clear signs of photobleaching and discoloration. It is found that the oxygen diffusion coefficient of the T sample is four and nine times slower than the TC and C samples, respectively, in the photobleached region. Fluorescence imaging and spectra and Raman spectra were taken before and after the accelerated test and indicate that discoloration causing fluorophores generation is higher after the photobleached region for transparent and combined EVAs, whereas higher at the center for UV-cut EVA laminates. A colorimeter was used to measure the Yellowness Index of the samples before and after the accelerated aging test. This work will help in the early detection of photobleaching and discoloration of any encapsulant used in the PV modules. This method will also help to study the behavior of encapsulants in different climatic conditions like hot, cold, dry, humid, and their combinations by simulating the same in an accelerated weathering chamber by using the different insulation thickness.
关键词： fluorophores,discoloration,photovoltaic module,photobleaching,ethylene-vinyl-acetate encapsulant
更新于2025-09-23 15:19:57
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Luminescent Solar Concentrators Based on Renewable Polyester Matrices
摘要： This study reports for the first time the use of bio-based alternatives for PMMA as host matrix for luminescent solar concentrators (LSCs). Notably, two types of renewable polyesters were synthesized in varying molar ratios via a two-step melt-polycondensation reaction with dibutyl tin oxide as catalyst. The first is a homopolymer of diethyl 2,3:4,5-di-O-methylene galactarate (GxMe) and isosorbide (IGPn), and the second is a random copolymer of GxMe with 1,3-propanediol and dimethyl terephthalate (GTPn). The two polyesters were found to be optically transparent, totally amorphous with a Tg higher than 45 8C and temperature resistance comparable to PMMA. Lumogen Red (LR) and an aggregation-induced emission (AIE) fluorophore, TPETPAFN, were utilized as fluorophores and the derived thin polymer films (25 mm) were found highly homogeneous, especially for those prepared from GTPn, possibly due to the presence of compatibilizing terephthalate units in the matrix composition and the higher molecular weight. The spectroscopic characterization and the optical efficiency determination (hopt) evidenced LSCs performances similar or superior to those collected from LR/PMMA thin films. Noteworthy, hopt of 7.7 % and 7.1 % were recorded for the GTPn-based matrix containing LR and TPETPAFN, respectively, thus definitely supporting the bio-based polyesters as renewable and highly high-performance LSCs.
关键词： luminescent solar concentrators,renewable host matrices,aggregation-induced emission,fluorophores,polyesters
更新于2025-09-23 15:19:57
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Photophysical Impact of Diacetylenic Conjugation on Classical Donor-Acceptor Electronic Energy Pair
摘要： Organic fluorophores with extended π-conjugation are important for their wide-spread applications. The present work provides photophysical insights of a diacetylene bridged classical donor-acceptor electronic energy pair, naphthalene-pyrene, in comparison with its part molecular structures, naphthyl and pyrenyl acetylenes as well as parent naphthalene and pyrene chromophores. The diacetylenic dye loses individual spectral identities of the donor and acceptor fluorophores exhibiting a locally excited (LE) emission (~411 nm) from the overall molecular entity with high fluorescence quantum yields (0.55–0.84) in non-aqueous media. In contrast to parent pyrene, the hybrid derivative shows strongly allowed S0→S1 transition. In mixed-aqueous media, the dye forms J-aggregates displaying a new red-shifted absorption (~425 nm) as well as emission (~510 nm) band. Unlike the hybrid dye, the naphthyl and pyrenyl acetylenes do not form aggregates. In the aggregate state of the hybrid fluorophore, electronic energy transfer takes place from the naphthyl moiety to pyrenyl ring. The excited state photophysical properties of the dye is exploited to vapor sensing in solid state.
关键词： vapor sensing,Organic fluorophores,donor-acceptor electronic energy pair,diacetylene bridged,naphthalene-pyrene,locally excited emission,J-aggregates,electronic energy transfer,π-conjugation,fluorescence quantum yields
更新于2025-09-23 15:19:57
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Metal enhanced fluorescence biosensing: from ultra-violet towards second near-infrared window
摘要： To increase disease survival rates, there is a vital need for diagnosis at very preliminary stages. Then, low concentrations of biomarkers are present which must be effectively detected and quantified for reliable diagnosis. Fluorescent biosensing is commonly enabled through the labelling of these biomarkers with nanostructures and fluorophores. Metal Enhanced Fluorescence (MEF) is a phenomenon whereby the intensity of a fluorescent biosensor signal can be considerably enhanced by placing a metallic nanostructure and fluorophore in close proximity. Importantly, this allows for an even lower detection limit and thus earlier diagnosis. In recent years, extraordinary efforts have been made in the understanding of how the chemical and physical properties of nanomaterials may be exploited advantageously. Via precise nanoscale engineering, it is possible to optimize the optical properties of plasmonic nanomaterials, which now need to be refined and applied in diagnostics. Through MEF, the intensity of this signal can be related in direct proportion to analyte concentration, allowing for diagnosis of disease at an earlier stage than previously. This review paper outlines the potential and recent progress of applied MEF biosensors, highlighting their substantial clinical potential. MEF biosensors are presented both upon assay-based platforms and in solution, with comments on the various metallic nanoparticle morphologies available. This is explored across various emission wavelengths from ultra-violet to the second near infrared window (NIR-II), emphasising their wide applicability. Further to this, the importance of near infrared (NIR-I and NIR-II) biosensing is made clear as it allows for higher penetration in biological media. Finally, by developing multiplexing techniques, multiple and simultaneous analyses of analytes can be achieved. Through the incorporation of metal enhanced fluorescence into biosensing, it will be possible to diagnose disease more rapidly and more reliably than before, with the potential to save countless lives.
关键词： nanomaterials,biosensing,Metal Enhanced Fluorescence,fluorophores,multiplexing,near-infrared
更新于2025-09-19 17:15:36
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[Advances in Heterocyclic Chemistry] || Recent developments in the synthesis of the BODIPY dyes
摘要： The BODIPYs are a very widely used class of fluorescent dyes, based around a heterocyclic organic framework, which have found applications across a broad range of research areas and real-world applications. Their popularity and utility derive from a winning combination of easily controllable photophysical properties and synthetic accessibility. Since their inception in 1968, considerable research has been directed toward the understanding, improvement, and development of flexible synthetic methodologies toward this privileged class of organic molecules. In this review we seek both to present an overview of commonly used synthetic methods and to highlight recent developments in the synthesis and modification of BODIPY dyes.
关键词： Dipyrromethene,Boron-chelated,Organic fluorophores,dipyrromethene,BODIPY,Synthesis,Dipyrromethane,4,40-Difluoro-4-bora-3a,4a-diaza-s-indacene
更新于2025-09-19 17:15:36