Coumarin Laser Dyes Research Articles

Enhanced energy transfer via surface plasmons in ternary liquid systems of coumarin-151, ethanol, and benzaldehyde

This investigation explores the plasmonic effect on molecular fluorescence within ternary liquid systems comprising 7-amino-4-(trifluoromethyl) coumarin (C-151) laser dye, ethanol, and benzaldehyde. A key aspect of our investigation involves examining ZrN nanosphere and ZrN nanoshell within these mixtures, marking the first instance of such an analysis in ZrN and ternary liquid compositions. Utilizing experimentally obtained refractive indices, we evaluate resonance peaks in the spectra and their shifts. Our findings reveal improved fluorescence characteristics in C-151 laser dye with the addition of ZrN nanoparticles. Theoretical results suggest that plasmonic nanoparticles play a significant role in enhancing dye fluorescence. These findings deepen our understanding of plasmonics in complex liquid environments and highlight ZrN's potential as an effective alternative plasmonic material for efficient molecular energy transfer at the nanoscale.

Exploration of the impact of graphene oxide, acetylenic gemini, and CTAT on the photophysical and aggregation properties of dipolar coumarin 153.

Advanced spectroscopic techniques have been utilized to study the interaction between the laser dye coumarin 153 (C153) and graphene oxide (GO) nanoparticles. GO was synthesized using a modified Hummers' method and characterized by UV-vis spectroscopy, Raman laser spectroscopy, FTIR-ATR spectroscopy, FESEM, HR-TEM, and XRD techniques. The GO@C153 composite was formed by mixing two aqueous solutions of GO and C153 due to their strong interaction through stacking and hydrophobic interactions. In this case, GO acts as an effective fluorescence quencher for C153 molecules, which undergo H-type aggregation in the presence of GO. The Stern-Volmer equation and time-dependent fluorescence studies were utilized to analyse the mechanism of fluorescence quenching. According to the findings, both static and dynamic quenching processes are responsible for the reduction in fluorescence intensity. The effect of surfactants (both cetyltrimethylammonium p-toluenesulfonate (CTAT) and synthesized N,N'-dihexadecyl-N,N,N',N'-tetramethyl-N,N'-but-2-ynediyl-di-ammonium chloride (16-4-16)) on the aggregation and photophysical properties of the dye was investigated using surface tensiometry, conductometry, UV-vis absorption spectroscopy, steady-state fluorescence measurements, DLS, and time-dependent fluorescence spectroscopy. Surfactants change the microenvironment of the C153 dye, leading to spectrum shifting and a higher quantum yield, which causes a rapid rise in fluorescence intensity in the micellar medium. It has been noted that in a micellar medium rather than in an aqueous one, the luminous intramolecular charge transfer (ICT) state of C153 stabilises. Lastly, we investigated the photophysical behavior of the GO-C153-micelle ternary system and discovered that, in the presence of a micellar medium, the quenched and blue-shifted (H-type aggregation) fluorescence peak of C153 (in the presence of GO) began to intensify once more. The main goal of this work is to create an effective and fairly cost powerful fluorescence sensor. Additionally, the ternary system (GO-C153-micelle) analytical idea can be employed to identify the onset of micelle formation. In wastewater treatment analysis, the GO-C153-surfactant ternary system concept can also be used to regenerate the adsorbent (in this case, GO) from dye molecules by allowing the dye molecules to exit the adsorbent and enter the micellar medium.

Absorption Spectrum and Raman Spectroscopy of Coumarin507 Dye Laser in Different Solvents

Coumarin dye laser compounds are often used as components in coloring agents and sprays., as well as in the odorization of foods. Therefore, the important of these compounds in many felids leading to growth of several ways aiming to advance the control of pharmaceutical and superficial producing. Solvents play an important role in changing the character of coumarin. The investigated spectral properties, as well as the effect of changing the solvent on this property, have been published. results referred that the molar electronic transition energy increased with decreasing the maximum absorption wavelength, and the highest intensity of the absorption spectrum was in the case of acetone solvent. In addition, many bands appear in Raman shift attributed to the ''C=O'' band, ''O=C–O, C–C'', and ''C–O'' deformation. The characteristic vibrations involving the ''O-H'' group is the stretching and bending modes of the ''O-H'' and ''C-O'' parts.

Structure-emission relationship of some coumarin laser dyes and related molecules: Prediction of radiative energy dissipation and the intersystem crossing rate constants.

Dye lasers are commonly used in optical investigation because their solutions in organic solvents deliver tunable, coherent emissions. They exhibit intense fluorescence owing to some specific spectroscopic characteristics. One drawback of the laser dyes is that it shows excessive triplet-state losses (TSLs.) The lack of theoretical predictions of fluorescence rates, intersystem crossing (ISC), and phosphorescence in laser dyes prompted us to report on the predicted rates of radiative and nonradiative transitions of some laser dyes. Structural engineering by some substituents influencing the simulated rates of coumarin laser dye derivatives for an efficient operation was investigated. The NH2 functional group renders the coumarin 120 more fluorescents with reduced TLS than the other investigated materials. Tailoring new efficient laser dyes can be achieved guided by the calculated rates of emission and nonradiative processes.

A Study on Optical Band Gap and Associated Band-Tails in Laser Dye Coumarin Doped Poly (Methyl Methacrylate) (PMMA) Films

Indian Journal of Scientific Research(IJSR):Calls for Unique, Unpublished research papers in Botany, Zoology, Chemistry, Physics, Mathematics, Medical Sciences, Agricultural Sciences, Environmental Sciences, Natural Sciences Technological Sciences and any other branch of related sciences

Time-resolved excited state dynamics of super-exciplex in the coumarin dye laser

It has been known for a few decades that laser dye, 7-diethylamino 4-methyl coumarin (DAMC) exhibits one absorption and one fluorescence peak but produces dual amplified spontaneous emission (ASE) bands (at 427 and 460 nm) in certain solvents, under high power pulsed laser pumping. The appearance of the new peak manifested only under high pump energy excitation, is attributed to a rare excited state species, called a “superexciplex” (SX). This is a transient excited state bimolecular association in which two excited state molecules get bonded with the help of an unexcited solvent molecule acting as an intermediary. In principle, the formation of excited state species would take a time of the order of a few hundred picoseconds or even nanoseconds. The objective of this paper is to delineate the formation of such super - exciplex employing time resolved ASE spectra where the three-dimensional display gives clearer perspectives. Since the formation of the SX depends on dye concentration, pump energy, and temperature, in the present time-resolved spectroscopy (TRS) paper all the above factors had been studied in some detail.

Binding, and thermodynamics of β-cyclodextrin inclusion complexes with some coumarin laser dyes and coumarin-based enzyme substrates: a simulation study

This paper addresses modelling the nature of interactions between β-CD and some coumarins including recently reported novel sulphur analogues to form inclusion complexes of appealing medicinal, photochemical and photophysical properties. The binding energy and the total stabilization energy (EONIOM) are used to confirm the most favorable inclusion complex structure. Thermodynamic parameters reveal exothermic inclusion reaction in gas phase. Thermal stability of fluorescent enzyme substrate of coumarin nucleus increases in the order: gas < cyclohexane < water, indicating better stability in water. Furthermore, molecular characteristics such as optimized geometries, MO’s and electrostatic potential energy map surfaces and energies are reported and correlated with some reactivity indices. Our results validated the experimentally available data reported in the literature. Inclusion complexes of β-CD with coumarins should result in improving its laser efficiency in environmentally benign aqueous medium.

Interaction of coumarin 6 with carbon nanotubes: Disintegration of the microcrystalline state by surfactant aggregation on the nanotube surface

The laser dye coumarin 6 (C6) readily forms microcrystals in water through π-π stacking and hence the compound loses its inherent fluorescence yield. However, the C6 molecules can be extracted from the aggregates by creating vicinal hydrophobic environment. Herein, we have used carboxylic acid derivatives of SWCNTs that could internalize the C6 microcrystals due to less microchannel polarity. Molecular C6 could be extracted from the microcrystals trapped inside the SWCNTs by inducing hydrophobicity developed by aggregating surfactants on the outer wall of the nanotube. Spectroscopic results prove the interaction and internalization of the C6 microcrystals in the SWCNT channel and disintegration by the externally adsorbed surfactants. Internalization of the C6 microcrystals has also been proved by a control experiment using solid silver nanoparticles coated with surfactant double layer.

Photoinduced formation of the laser dye coumarin 6 from its dihydro derivatives

The dihydro form of the laser dye Coumarin 6 and its acylated derivatives undergo photoinduced transformations with Coumarin 6 formation. The reactions go easily both in organic solvents and in polymer films with a high increase of fluorescence. Irreversibility of the reaction provides potential use of the new photosensitive media for optical information recording and sensing technologies.

Photostability of Coumarin Laser Dyes - a Mechanistic Study Using Global and Local Reactivity Descriptors.

Using density functional theory approach, the trend in photostability of fluorescent coumarin laser dyes were investigated with the help global reactivity descriptors. The effect of different basis sets on global reactivity descriptors i.e. electrophilicity index (ω) is studied. The local reactivity descriptors such as Fukui function, local softness and local electrophilicity index have been used to understand the reactive site in the molecule. Photodegradation mechanism of fluorescent coumarin laser dyes in presence of singlet oxygen is explained using density functional theory.

Diode-pumped dye laser

This letter reports diode pumping for dye lasers. We offer a pulsed dye laser with an astigmatism-compensated three-mirror cavity and side pumping by blue laser diodes with 200 ns pulse duration. Eight dyes were tested. Four dyes provided a slope efficiency of more than 10% and the highest slope efficiency (18%) was obtained for laser dye Coumarin 540A in benzyl alcohol.

Fourier transform infrared spectroscopy for irradiation coumarin doped polystyrene polymer films by alpha ray

FTIR spectroscopy has been in use broadly to study microscopic areas in polymers for the last years. The FTIR transmission spectra of coumarin laser dye, polystyrene and coumarin doped polystyrene films with different doping ratio of coumarin solution have been studied. These spectra measured and explained for all films before and after Alpha irradiation with different irradiation times. All samples prepared by casting method. FTIR corroborate chemical bonds of coumarin dye molecules and polystyrene films by producing an IR absorption spectrum when increasing doping ratio of coumarin solution and when irradiation by Alpha source. There are some bonds disappeared after irradiation.

Synthesis, linear optical, non-linear optical, thermal and mechanical characterizations of dye-doped semi-organic NLO crystals

Organic laser dyes Coumarin 485, Coumarin 540 and Rhodamine 590 Chloride were used to dope potassium acid phthalate crystals (KAP). Dye-doped KAP crystals with different dye concentrations such as 0.01 mM, 0.03 mM, 0.05 mM, 0.07 mM and 0.09 mM (in the KAP growth solution) were grown. The linear optical, non-linear optical, mechanical and thermal characterizations of dye-doped KAP crystals were studied and compared to understand the effect of dye and dye concentration on the KAP crystal. Absorption and emission studies of KAP and dye-doped KAP single crystals indicated the inclusion of the dye into the KAP crystal lattice. The effect of dye and its concentration on the SHG efficiency of the KAP crystal was studied using the Kurtz and Perry powder technique. It was observed that the absorption maximum wavelength and concentration of the dye used for doping the KAP single crystal decided the SHG efficiency of the dye-doped KAP single crystals. The mechanical hardness of the dye-doped and undoped (pure) KAP single crystals were studied using the Vickner’s microhardness test. It was observed that doping the KAP crystals with the laser dyes changed them from softer material to harder material. Etching studies showed an improvement in the optical quality of the KAP crystal after doping with laser dyes.

Synergistic effect of intramolecular charge transfer toward supramolecular pKa shift in cucurbit[7]uril encapsulated coumarin dyes.

This article presents the process and mechanism of supramolecular pKa shift in two bichromophoric coumarin laser dyes, namely, coumarin 7 (C7), (ΔpK(a) = 4.6) and coumarin 30 (C30), (ΔpK(a) = 3.0), achieved by introducing a synthetic macrocyclic receptor, cucurbit[7]uril (CB7), in aqueous media. The intramolecular charge transfer, from the diethylamino coumarin moiety toward the benzimidazolyl moiety and its protonation, even at pH ∼8, is facilitated by the interaction of the cucurbituril host in a 2:1 (CB7/dye) stoichiometric ratio. The CB7 macrocycle interacts with C7/C30 dyes in a stepwise manner with binding constants of the order of K(1) ≅10(5) M(-1), K2 ≅10(4) M(-1) for both C7 and C30 dyes. This study underlines a structure-property relationship to explain the host induced changes in the stereoelectronic distributions in the guest dyes supporting the supramolecular pK(a) shifts and is appropriately established by both experimental and theoretical considerations. On the other hand, the increased solubility (>250 times) and enhancement in fluorescence intensity (>13-fold) of the coumarin dyes in the presence of CB7 also find applications for developing aqueous dye laser systems where this supramolecular strategy will largely suppress the disadvantages of low solubility, aggregation, lower emission, or low stability of the dye in aqueous medium.

White light emission with red-green-blue lasing action in a disordered system of nanoparticles

White light emission from a disordered system with intensity feedback is investigated. The gain material is an ethanol solution with three laser dyes (Coumarin 440, Coumarin 6, Oxazine), and titanium dioxide (TiO2) nanoparticles to provide feedback. A single pulsed laser beam at 355 nm with 8 ns pulse duration is used to pump the dyes. Coumarin 440 and Coumarin 6 are excited first by the pump beam, and part of the Coumarin 6 peak pumps Oxazine. Bright white light emission is obtained by combining blue, green, and red beams with a threshold effect. The working properties and system emission characteristics are discussed.

Spectroscopic Characterization of Coumarin-Stained Beads: Quantification of the Number of Fluorophores Per Particle with Solid-State19F-NMR and Measurement of Absolute Fluorescence Quantum Yields

The rational design of nano- and micrometer-sized particles with tailor-made optical properties for biological, diagnostic, and photonic applications requires tools to characterize the signal-relevant properties of these typically scattering bead suspensions. This includes methods for the preferably nondestructive quantification of the number of fluorophores per particle and the measurement of absolute fluorescence quantum yields and absorption coefficients of suspensions of fluorescent beads for material performance optimization and comparison. Here, as a first proof-of-concept, we present the first time determination of the number of dye molecules per bead using nondestructive quantitative ((19)F) NMR spectroscopy and 1000 nm-sized carboxylated polystyrene particles loaded with varying concentrations of the laser dye coumarin 153 containing a CF(3) group. Additionally, the signal-relevant optical properties of these dye-loaded particles were determined in aqueous suspension in comparison to the free dye in solvents of different polarity with a custom-built integrating sphere setup that enables spectrally resolved measurements of emission, transmission, and reflectance as well absolute fluorescence quantum yields. These measurements present an important step toward absolute brightness values and quantitative fluorescence analysis with particle systems that can be exploited, for example, for optical imaging techniques and different fluorescence assays as well as for the metrological traceability of fluorescence methods.

Non-covalent interactions of coumarin dyes with cucurbit[7]uril macrocycle: modulation of ICT to TICT state conversion

Non-covalent interaction of coumarin laser dyes, namely coumarin-1 (C1), coumarin-481 (C481) and coumarin-6H (C6H), with a versatile macrocyclic host molecule cucurbit[7]uril (CB7), has been investigated in aqueous solution using photophysical methods. Steady-state and time-resolved fluorescence studies illustrate significant enhancements/modifications in the fluorescence yields, lifetimes and spectral features of C1, C481 and C6H on interaction with CB7, and are assigned to 1 : 1 complex formation between the dyes and the CB7 host. The complex formation is mainly driven by charge-dipole interaction, as evident from the binding constant values (K ~ 10(4)-10(5) M(-1)). The large changes in the excited state behaviour of C1 and C481 as compared to C6H in the presence of CB7 indicate that CB7 binds C1 and C481 through the encapsulation of the 7-N,N'-diethylamino group of the dyes and the structural rigidity imposed by this interaction dramatically alters the excited state properties of the dyes by preventing the conversion of their emissive intramolecular charge transfer (ICT) state to the non-radiative twisted intramolecular charge transfer (TICT) state. The present results direct towards the probable supramolecular approach using water soluble macrocyclic CB7, in the development of aqueous dye laser systems in the blue-green region.

Molecular Origins of Optoelectronic Properties in Coumarin Dyes: Toward Designer Solar Cell and Laser Applications

Coumarin derivatives are used in a wide range of applications, such as dye-sensitized solar cells (DSCs) and dye lasers, and have therefore attracted considerable research interest. In order to understand the molecular origins of their optoelectronic properties, molecular structures for 29 coumarin laser dyes are statistically analyzed. To this end, data for 25 compounds were taken from the Cambridge Structural Database and compared with data for four new crystal structures of coumarin laser dyes [Coumarin 487 (C(19)H(23)NO(2)), Coumarin 498 (C(16)H(17)NO(4)S), Coumarin 510 (C(20)H(18)N(2)O(2)), and Coumarin 525 (C(22)H(18)N(2)O(3))], which are reported herein. The competing contributions of different resonance states to the bond lengths of the 4- and 7-substituted coumarin laser dyes are computed based on the harmonic oscillator stabilization energy model. Consequently, a positive correlation between the contribution of the para-quinoidal resonance state and the UV-vis peak absorption wavelength of these coumarins is revealed. Furthermore, the perturbations of optoelectronic properties, owing to chemical substituents in these coumarin laser dyes, are analyzed: it is found that their UV-vis peak absorption and lasing wavelengths experience a red shift, as the electron-donating strength of the 7-position substituent increases and/or the electron-withdrawing strength of the 3- or 4-position substituent rises; this conclusion is corroborated by quantum-chemical calculations. It is also revealed that the closer the relevant substituents align with the direction of the intramolecular charge transfer (ICT), the larger the spectral shifts and the higher the molar extinction coefficients of coumarin laser dyes. These findings are important for understanding the ICT mechanism in coumarins. Meanwhile, all structure-property correlations revealed herein will enable knowledge-based molecular design of coumarins for dye lasers and DSC applications.

A novel method for the synthesis of coumarin laser dyes derived from 3-(1H-benzoimidazol-2-yl) coumarin-2-one under microwave irradiation

We want to achieve the synthesis of 3-(1H-benzoimidazol-2-yl)-7-(diethylamino) coumarin-2-one (1), 3-(1H-benzoimidazol-2-yl)-7-(dimethylamino) coumarin-2-one (2), 3-(1H-benzoimidazol-2-yl) coumarin-2-one (3) that are important dyes in industries (Soko owska et al., 2001). Methods for the synthesis of some of these compounds have been the title in some pervious patents, but enough information about separation and purification of them was not clearly indicated. We carried out several methods for the synthesis of the mentioned compound and purification with different yields. Now, we can synthesise these dyes under microwave irradiation in solid phase and solvent free methods with 80% yield, which is a high and remarkable percentage.

Effect of anisotropic and isotropic solvent on the dipole moment of coumarin dyes

The ground state ( μ g) and the excited state ( μ e) dipole moments of two coumarin laser dyes, coumarin 440 and 460, were studied at room temperature in various solvents, viz., general solvents, alcohols and liquid crystals at 298 K. In this work, we report dipole moment of laser dyes in different anisotropic (liquid crystal) and isotropic environments for understanding the effects of environments on the molecular dipole moment and comparing them. Ground and excited state dipole moments of coumarin dyes were evaluated by means of solvatochromic shift method. It was observed that dipole moment values of excited states ( μ e) were higher than the corresponding ground state values ( μ g) in all media.