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Excimer based FRET between non-FRET pair flourophores aided by the aromatic moiety of anionic surfactants: An experimental observation
摘要： A new FRET pair has been reported based on the apperance of excimeric emission and hence significant spectral overlap between an otherwise non-FRET pair fluorophores viz pyrene and rhodamine 6G in the anionic sodiumdodecylbenzenesulfonate (SDBS) micellar system. The occurence of FRET based on such modulation of spectral overlap integral has not been dealt with in detail in comparison to the other FRET parameters like distance between the fluorophores and orientation. Due to the presence of benzene ring in the SDBS micellar system the formation of excimers is augemented due to the π?π interactions between the pyrene molecules and the benzene units of the surfactants. The excimeric pyrene has a bathochromically shifted peak which overlaps with the absorption peak of rhodamine 6G thereby giving rise to energy transfer as FRET between these otherwise non-FRET pair molecules. The efficiency of FRET between the pyrene and rhodamine 6G can be modulated by the degree of spectral overlap between the excimeric peak of pyrene and the absorption peak of rhodamime6g. All the experiments were carried in the Sodiumdodecylsulfate (SDS) micellar system also, which unlike SDBS does not possess any benzene unit, in order to compare the results of excimer formation as well the FRET process.
关键词： rhodamine 6G,Pyrene,overlap integral,Excimer,FRET
更新于2025-11-19 16:46:39
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Benzo[ghi]perylene & Coronene as Ratiometric Reversible Optical Oxygen Nano-Sensor
摘要： The development of novel single molecular probe based optical ratiometric oxygen sensor with simple fabrication, high sensitivity, and linear response is highly desirable. Herein, benzo[ghi]perylene (BzP) and coronene (Cron) were explored as dual-emissive ratiometric oxygen nano-sensor that displayed linear plots at a low probe concentration (6 μM). The sensor fabrication was simple, and the probes exhibited efficient fluorescence quenching of monomer emission by molecular oxygen. However, the excimer emission of probe remained unaffected. Thus a ratiometric method is developed based on the dual emitting luminophore. The method can be used to estimate dissolved oxygen in liquids and 5 – 100 % of oxygen concentration in gaseous mixtures.
关键词： Coronene,Benzo[ghi]perylene,Oxygen sensing,Excimer emission,Ratiometric sensor,Fluorescence probe
更新于2025-11-14 17:04:02
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Solvent-Dependent Sensitization of Ytterbium and Neodymium via an Intramolecular Excimer
摘要： We report the synthesis of a di(1-pyrenyl)-phosphoryl acetophenone ligand containing two pyrenyl moieties linked by a single phosphorus atom. The ligand exhibits solvent-dependent emission: in nonpolar solvents, typical monomeric pyrene emission is observed, whereas in polar solvents, an additional broad and structureless emission appears. The emission in polar solvents is concentration independent and is attributed to the emission of an intramolecular excimer. The coordination of the di(1-pyrenyl)phosphoryl acetophenone ligand as well as the corresponding deprotonated anionic di(1-pyrenyl)phosphoryl acetophenonate ligand was studied with the near-infrared emitting lanthanides, neodymium and ytterbium. Solvent-dependent sensitization of both lanthanides was observed and correlates with the presence of the excimer emission. Sensitization of ytterbium is more efficient than neodymium, and the overall quantum yields were found to be 12.8 and 1.9% for ytterbium and neodymium, respectively.
关键词： solvent-dependent emission,quantum yields,ytterbium,neodymium,intramolecular excimer,lanthanides
更新于2025-11-14 15:24:45
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Paintable Room Temperature Phosphorescent Liquid Formulations of Alkylated Bromonaphthalimide
摘要： Organic phosphors have been widely explored with an understanding that crystalline molecular ordering is a requisite for enhanced intersystem crossing. In this context, we explore the room temperature phosphorescence features of a solvent-free organic liquid phosphor in air. Given alkyl chain substitution varied the physical states of bromonaphthalimides, phosphorescence remained unaltered for the solvent-free liquid in air. As the first report, a solvent-free liquid of a long swallow tailed bromonaphthalimide exhibits room temperature phosphorescence in air. Doping of the phosphor with carbonyl guests resulted in enhanced phosphorescence and hence a large area paintable phosphorescent liquid composite with improved lifetime and quantum yield is developed.
关键词： phosphorescence,organic liquids,excimer,luminescent thermometer,liquid phosphor
更新于2025-09-23 15:23:52
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Surface Pretreatment of Fiber-Reinforced Plastics via VUV Radiation
摘要： Fiber-reinforced plastics (FRP) are of great importance for the transport sector, the aerospace industry, for wind power plants, in the building sector and in the field of sports and leisure applications. Optimization of the adhesive bonding process for FRP structures, especially the surface preparation prior to bonding, will be of a central importance in forthcoming expansion of FRP use. In this connection the key problem depends on the FRP polymer matrix. In the case of duroplastic matrix the main problem is the presence of release agent on the surface of joining components. For the thermoplastic matrix such as polypropylene (PP), the main problems are the low surface energy and the inertness of its surface. Conventional pretreatment methods, such as manual grinding, shall be replaced by energetic radiation technics like VUV lamps (vacuum ultraviolet spectral range: 100 – 200 nm). This approach is a non-contact method, characterized by high treatment homogeneity and material-saving properties, combined with no further fibers to be released. The surface of the thermoplastics is activated by the incorporation of oxygen, release agent contamination on the thermoset is cleaned or modified [1 - 8]. The results of the VUV surface activation of PP and CFRP with regard to the incorporation of functional groups, increase of surface energy, matrix degradation and the adhesion increase of adhesive bonds are presented. In addition, studies on the release agent coating and the release agent modification by VUV radiation are presented. The work is completed by considerations concerning possibilities to accelerate the process (in particular, wavelength dependence, influence of an inert gas or the moisture content). Finally, an evaluation of the VUV pretreatment is carried out on the basis of two specific applications.
关键词： VUV,irradiation,excimer,release agent,surface pretreatment,CFRP,FRP,GRP
更新于2025-09-23 15:22:29
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Diphenylisobenzofuran Bound to Nanocrystalline Metal Oxides: Excimer Formation, Singlet Fission, Electron Injection, and Low Energy Sensitization
摘要： We report the photophysical properties of the dicarboxylated diphenylisobenzofuran dye (1) bound to nanocrystalline metal oxide surfaces. With increased surface loading of 1, emission from the films is significantly quenched but with a small amount of excimer emission at maximum surface loadings. Long-lived triplets were observed by ns TA spectroscopy that is consistent with singlet fission occurring on mesoporous ZrO2. The evolution of these triplets however could not be convincingly resolved by our sub-nanosecond TA spectroscopy. Dye-sensitized devices composed of 1 on a TiO2|Al2O3 core-shell structure exhibited an unusual decrease, increase, and then decrease in Jsc with respect to the thickness of Al2O3. In these films the Al2O3 acts as a tunneling barrier to slow electron injection from the singlet excited state such that singlet fission, and electron injection from the triplet state become competitive. Proof-of-principle self-assembled bilayer films that exhibit efficient triplet energy transfer from a low energy absorbing dye to 1 is demonstrated as another step towards a SF-based DSSC that can circumvent the Shockley-Queisser limit.
关键词： low energy sensitization,excimer formation,singlet fission,electron injection,diphenylisobenzofuran,nanocrystalline metal oxides
更新于2025-09-23 15:21:21
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The Global Market for Industrial Laser Processing
摘要： The Global Market for Industrial Laser Processing. Fiber laser revenues dictate total-industry negative performance in 2019. Global industrial laser revenues, over the period 2010 – 19, show a period of strong CAGR growth (11.5 %) led by the dynamic markets for high-power fiber lasers used in sheet metal cutting and a significant application for excimer lasers (smart phones). In 2019, global laser revenues decreased for only the first time since the recession of 2009, mainly for two reasons: unconstrained fiber laser selling price decreases and the maturation of the application for excimer lasers. Strong competition in the Chinese market – now more than 40 % of the world market – drove down the average selling price of industrial lasers by 17.5 % in 2019 while unit sales were up 6.5 % in the same period.
关键词： fiber laser,market revenues,excimer laser,industrial laser,CAGR
更新于2025-09-23 15:21:01
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Ablation of piezoelectric polyvinylidene fluoride with a 193 nm excimer laser
摘要： The unique flexible and piezoelectric properties of polyvinylidene fluoride (PVDF) films would allow for new applications for integrated bioelectronic devices. The use of these films has been precluded by the difficulty in machining them into small, discrete features without damaging the properties of the material. The etching of piezoelectric PVDF by means of a 193 nm excimer laser is explored and characterized. Etch rates are shown for common laser fluence values, along with images of the quality of the cuts to provide the reader with an understanding of the compromise between etch rate and edge roughness. The authors describe a novel method for the etching of piezoelectric, β-phase PVDF. While PVDF is flexible, acoustically matched to biological tissue, and has a wide resonance bandwidth, it is often overlooked as a piezoelectric material for micro-electrical-mechanical-system devices because of the difficulty in fabrication. In this paper, the authors characterize the etch rate and quality while using a 193 nm argon fluoride excimer laser for patterning.
关键词： excimer laser,etching,piezoelectric,ablation,PVDF
更新于2025-09-23 15:21:01
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Current review of Excimer laser Trabeculostomy
摘要： Background: Excimer laser trabeculostomy (ELT) is a microinvasive glaucoma surgery (MIGS) that creates multiple laser channels through the trabecular meshwork using a cold laser system, which minimizes tissue fibrosis and aids in bypassing the main area of resistance to aqueous outflow. The purpose of this review is to evaluate the current body of evidence surrounding ELT in terms of efficacy and review the safety profile of the procedure. Main text: Studies screened had to show clear inclusion and exclusion criteria as well as well-defined outcome measures. PubMed, MEDLINE, EMBASE and the Cochrane Controlled Trial Database were searched. Preferred Reporting Items of Systematic Reviews (PRISMA) guidelines were used to assess for study quality and for any bias. Sixty-four articles were initially identified with 18 meeting preliminary screening criteria. Ultimately, 8 studies met inclusion criteria and 2 additional non-referenced publications were also included: 1 randomized control trial, 4 prospective case series and 5 retrospective studies. Overall studies showed moderate intraocular pressure (IOP) lowering of between 20% and 40% from baseline without medication washout and mostly a decrease in glaucoma medications with few complications. Conclusion: Current literature shows a significant IOP-lowering effect of ELT with a favorable safety-profile in standalone cases or combined with cataract surgery. Limitations to these studies are the lack of controls and washout IOP. Overall, ELT is an attractive MIGS option that does not require any residual device remaining in the angle.
关键词： Excimer laser trabeculostomy,ELT,Trabeculotomy,MIGS,Cataract,Intraocular pressure,Glaucoma
更新于2025-09-23 15:21:01
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Ice Confinement-Induced Solubilization and Aggregation of Cyanonaphthol Revealed by Fluorescence Spectroscopy and Lifetime Measurements
摘要： When an aqueous salt solution freezes, a freeze concentrated solution (FCS) separates from ice. The properties of the FCS may differ from those of a supercooled bulk solution of the same ionic strength at the same temperature. The fluorescence and lifetime characteristics of 6-cyano-2-naphthol (6CN) were studied in frozen NaCl solutions to provide an insight into the solution properties of the FCS. While the photoacidity of 6CN in an FCS is similar to that in solution, several anomalous behaviors are observed. Fluorescence spectra indicate that the solubility of 6CN is significantly enhanced in the FCS (50 mM or higher) compared to that in bulk NaCl solution, where the solubility limit is 250 μM. The high solubility induces aggregation of 6CN in the FCS, which is not detected in bulk solutions. This trend becomes marked as the initial NaCl concentration decreases, that is, the FCS is confined in a small space. The fluorescence lifetimes of 6CN in the FCS support the spectroscopy results. In addition to the species identified by fluorescence spectroscopy, excimers are assigned from lifetime measurements in the FCS. The excimer formation is also a result of the enhanced solubility of 6CN in the FCS.
关键词： solubility enhancement,aggregation,lifetime measurements,excimer formation,6-cyano-2-naphthol,freeze concentrated solution,Fluorescence spectroscopy
更新于2025-09-23 15:19:57