Fluorescence quantum yields of some rhodamine dyes

Kubin, R. F.; Fletcher, A. N.

doi:10.1016/0022-2313(82)90045-x

Cited by 1,108 publications

(733 citation statements)

References 5 publications

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“…We followed the step by step procedure detailed in Ref. 24. The "band narrowing" was performed in TBE buffer.…”

Section: E Surface Characterization and Solubilitymentioning

confidence: 99%

“…In that study, the emission peak dramatically broadened from a significant contribution from trapped states. The QYs of nanocrystals are smaller than the QYs of organic dyes, 24 but they only weakly depend on the buffer conditions. The nanocrystals' longer lifetime under CW irradiation partially compensate for this overall lower emission intensity.…”

Section: B Optical Characterizationmentioning

confidence: 99%

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Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

et al. 2001

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We describe the synthesis of water-soluble semiconductor nanoparticles, and discuss and characterize their properties. Hydrophobic CdSe/ZnS core/shell nanocrystals with a core size between 2 and 5 nm are embedded in a siloxane shell and functionalized with thiol and/or amine groups. Structural characterization by AFM indicates that the siloxane shell is 1-5 nm thick yielding final particle sizes of 6-17 nm, depending on the initial CdSe core size. The silica coating does not significantly modify the optical properties of the nanocrystals. Their fluorescence emission is about 32-35 nm FWHM, and can be tuned from blue to red with quantum yields up to 18%, mainly determined by the quantum yield of the underlying CdSe/ZnS nanocrystals. Silanized nanocrystals exhibit enhanced photochemical stability over organic fluorophores. They also display high stability in buffers at physiological conditions (>150 mM NaCl). The introduction of functionalized groups onto the siloxane surface would permit the conjugation of the nanocrystals to biological entities. 2 IntroductionRecent progress in wet chemistry has established a robust route towards the synthesis of highly luminescent semiconductor nanocrystals having sizes ranging from 1.5 to 8 nm. 1,2 By judiciously controlling the growth conditions, the size, and even the shape of II-VI nanocrystals can be accurately tailored. 3,4 The ability to control these parameters has a profound impact in materials science since it can be harnessed for engineering assemblies of nanometer scale units with novel characteristics. [5][6][7][8] At this point, the prominent focus has been the optical properties of these semiconductor nanocrystals. They are governed by strong quantum confinement effects and, therefore, are size dependent. 2,9,10 The absorption onset and fluorescence emission shift to larger energy with decreasing size.Moreover, while the absorption spectrum is a continuum from the bandgap into the UV, the emission pattern is narrow, symmetric, and does not depend on the excitation frequency. Several different sizes of nanocrystals can thus be excited simultaneously with a single excitation source, resulting in well-resolved colors of emission. Further passivation of the nanocrystal surface by a thin shell of a higher band gap material does not significantly modify the absorption and emission features but increases the nanoparticle quantum yield up to 50-70%. [11][12][13] The passivation shell also imparts an efficient photochemical stability, so that the photobleaching is reduced, and the number of photons a single nanocrystal can emit dramatically increases. The ability to discriminate many different colors simultaneously under long-term excitation holds great promise for fluorescent labeling technologies, especially in biology. 14,15 In this respect, organic dye molecules suffer from several limiting factors.First, their narrow absorption bands make it difficult to excite several colors with a single 3 excitation source. In addition, due to the large spectral overlaps between t...

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“…We followed the step by step procedure detailed in Ref. 24. The "band narrowing" was performed in TBE buffer.…”

Section: E Surface Characterization and Solubilitymentioning

confidence: 99%

Section: B Optical Characterizationmentioning

confidence: 99%

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

et al. 2001

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“…Where Φ s is the fluorescence quantum yield of the standard (rhodamine B in ethanol, 0.65, 25°C) [2] , To determine the quantum yield of NBD in nanoparticle system, we first need to measure the actual absorbance of NBD (at 490 nm) in nanoparticle system. Since the NBD/nanoparticle complex dispersion exhibits relatively strong light scattering effect (as shown in Figure S5), to eliminate the error caused by light scattering effect, we also measured the absorption spectrum for the neat nanoparticles (with neither NBD nor spiropyran), and the actual absorbance value for NBD at 490nm can be obtained by the deduction of the absorbance of neat nanoparticle dispersion at 490nm from the apparent absorbance value of NBD/neat nanoparticle dispersion.…”

Section: Characterizationsmentioning

confidence: 99%

A Core–Shell Nanoparticle Approach to Photoreversible Fluorescence Modulation of a Hydrophobic Dye in Aqueous Media

Chen

Zeng

et al. 2008

Chemistry A European J

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Amphiphilic core–shell nanoparticles containing spiropyran moieties have been prepared in aqueous media. The nanoparticles consist of hydrophilic and biocompatible poly(ethyleneimine) (PEI) chain segments, which serve as the shell, and a hydrophobic copolymer of methyl methacrylate (MMA), a spiropyran‐linked methacrylate, and a cross‐linker, which forms the core of the nanoparticles. A hydrophobic fluorescent dye based on the nitrobenzoxadiazolyl (NBD) group was introduced into the nanoparticles to form NBD–nanoparticle complexes in water. The nanoparticles not only greatly enhance the fluorescence emission of the hydrophobic dye NBD in aqueous media, probably by accommodating the dye molecules in the interface between the hydrophilic shells and the hydrophobic cores, but also modulate the fluorescence of the dye through intraparticle energy transfer. This biocompatible and photoresponsive nanoparticle complex may find applications in biological areas such as biological diagnosis, imaging, and detection. In addition, this nanoparticle approach will open up possibilities for the fluorescence modulation of other hydrophobic fluorophores in aqueous media.

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“…The refractive index n(p) of ethanol was determined from the proportionality between the increment ∆n(p) and the Eulerian strain, 35 which is a function of only the density, taking n(p) values ( Thermometric measurements based on changes in luminescence intensity with temperature are widely used to determine local temperature distributions. 38,39 Rhodamine dyes are favorably employed for such studies due to good chemical stability and high quantum yield, 40 although there are substances having a larger temperature sensitivity. 41 More rarely, changes in wavelength are harnessed for thermometry, probably due to the necessity of a sufficiently accurate spectrometer.…”

Section: Discussionmentioning

confidence: 99%

Indicating pressure and environmental effects by means of the spectral shift with rhodamine B and fluorescein

Johann

2015

AIP Advances

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Fluorescence absorption and emission wavelengths can be influenced by environmental conditions, such as pressure, temperature and concentration. Here those effects are explored with an emphasis on determining the potential of rhodamine B and fluorescein as high-pressure indicators. The red shift of the emission peak maxima of rhodamine B and fluorescein are investigated in dependence of pressure up to 200 MPa using as the solvents water, ethanol and poly(dimethylsiloxane) (PDMS) with rhodamine B and water, polystyrene beads and melamine resin beads with fluorescein. Emission spectra recording and peak fitting is done automatically at time intervals of down to a second and with 0.3 nm wavelength resolution. The wavenumber-pressure relation for rhodamine B reveals increasing divergence from linear behavior in the sequence of the solvents water, ethanol and silicone rubber. Graphical correlation of the data diverging only slightly from linearity with a selection of polarity functions is enabled using the concept of 'deviation from linearity (DL)' plots. Using the example of rhodamine B dissolved in PDMS elastomer it is shown that there is a temperature induced irreversible molecular reordering, when scanning between 3 and similar to 50 degrees C, and a polarity change in the proximity of the embedded dye molecule. Swelling studies are performed with PDMS containing rhodamine B, where the elastomer is first put in water, then in ethanol and again in water. There a complex solvent exchange process is revealed in the elastomer demonstrating the feasibility of fluorescence spectroscopy, when observing variations in wavelength, to indicate and enlighten molecular rearrangements and swelling dynamics in the polymer, and polarity changes and solvent exchange processes in the dye solvation shell

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Fluorescence quantum yields of some rhodamine dyes

Cited by 1,108 publications

References 5 publications

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

Synthesis and Properties of Biocompatible Water-Soluble Silica-Coated CdSe/ZnS Semiconductor Quantum Dots

A Core–Shell Nanoparticle Approach to Photoreversible Fluorescence Modulation of a Hydrophobic Dye in Aqueous Media

Indicating pressure and environmental effects by means of the spectral shift with rhodamine B and fluorescein

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