Optical properties of BBOT-doped silica films prepared via sol–gel processing

Wang, Junling; He, Zhengjie; Mao, Huaxiang; Du, Yufan; Wang, Yongsheng

doi:10.1016/j.jlumin.2006.01.137

Cited by 5 publications

(6 citation statements)

References 9 publications

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“…These were calculated using an integrating sphere and by integrating over the entire range of the emission wavelengths relative to the scattering of the pure solvent . The concentration-dependent spectral changes are similar to those observed for interchain π-stacking of conjugated polymers in thin films. , Although the concentration-dependent emission shifts of BBT are real, an inner filter effect cannot be entirely dismissed. This is in part because of the unknown effect of light scattering from BBT aggregates in PBS films.…”

Section: Resultsmentioning

confidence: 78%

“…As a result of its collective optical properties that can be visibly tracked by the naked eye concomitant to its solubility in a broad range of process compatible solvents, BBT has found many optical applications. These include the use as an optical brightener, and as a whitening agent in many polymers and textiles, in addition to uses in various optoelectronic applications. − BBT further shows excellent heat stability, and it can be used to improve the color of various plastics.…”

Section: Introductionmentioning

confidence: 99%

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Photophysical, Electrochemical and Crystallographic Investigations of the Fluorophore 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene

et al. 2011

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The photophysics of 2,5-bis(5-tert-butyl-benzoxazol-2-yl)thiophene (BBT) were investigated for assessing its limitations for use as a universal fluorophore and as a viable sensor for both polymeric and solution studies. This is of importance given the limitations of currently used materials. BBT's steady-state and time-resolved fluorescence were additionally investigated to correlate its solid-state features, observed by fluorescence spectroscopy when mixed in poly(1,4-butylene succinate) (PBS) films, with its single crystal characteristics. The conjugated fluorophore was found to be highly fluorescent, with absolute quantum yields of (Φ(fl)) ≥ 0.60. The Φ(fl) values were high, regardless of solvent polarity and proticity and whether alone or in polymeric films. The major competitive fluorescence quenching pathway was found to occur by intersystem crossing to the triplet state. This was confirmed by laser flash photolysis in which the BBT triplet absorbed at 500 nm. The triplet transient was confirmed by quenching studies with 1,3-cyclohexadiene. Meanwhile, nonradiative deactivation of BBT's singlet excited state by internal conversion was found to be negligible. In solution and especially when distributed in semicrystalline PBS, BBT exhibits spectral changes and a bathochromic shift as a function of concentration due to aggregation of ground state molecules, which is present even at low BBT concentrations. Consistent monoexponential lifetimes on the order of ∼2 ns were observed regardless of solvent and independent of both the excitation wavelength and concentration. The constant excited state kinetics confirm the absence of a singlet excited state deactivation by excimer formation. The electrochemistry of BBT demonstrated that it is irreversibly oxidized and the resulting radical cation is unstable. Conversely, the cathodic process, resulting in the radical anion, is reversible, confirming its n-doping character. Crystallographic studies revealed that the planes described by the benzoxazolyl moieties are twisted from the plane described by the central thiophene. Several weak C-H···π and π-π intermolecular interactions were also observed. BBT's high solubility in common solvents combined with its measured enhanced optoelectronic properties make it a candidate as a universal fluorophore reference and smart material for both polymeric and solution studies.

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Section: Resultsmentioning

confidence: 78%

Section: Introductionmentioning

confidence: 99%

Photophysical, Electrochemical and Crystallographic Investigations of the Fluorophore 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene

et al. 2011

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“…The raw materials, tetraethyoxysiliane (TEOS), HCl, BBOT, Lumogen (from BASF), Coumarin Dioxane, ethanol, methanol and dimethylformamide were used without further purification. The preparation steps were similar to ref [8]. Dioxane was selected as co-solvent.…”

Section: Methodsmentioning

confidence: 99%

“…Not to mention that a kind of sol-gel process can co-doped multiple fluorescent dyes. Based on BBOT-doped silica and Lumogen-doped silica obtained in our group individually [8,9] , we synthesized RGB fluorescent dyes co-doped silica and characterized their PL properties and analyzed their interaction. So this provided one method to enrich inorganic luminescent materials.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Photoluminescence of Red, Green and Blue Fluorescent Dyes Co-Doped Nanoporous Silica by a Sol-Gel Method

Wang

Zhou

et al. 2014

AMM

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One sol-gel method is explored to prepare red, green and blue (RGB) fluorescent dyes co-doped nanoporous silica at low temperature in air. All of the dyes covers blue-emitting 2, 5-bis (5-tert-butyl-2-benzoxazolyl)- thiophene (BBOT), green-emitting Coumarin 152A (Coumarin) and red-emitting Lumogen red R305 (Lumogen), contributing to the photoluminescence (PL) of the hybrid. As a key factor, the molar ratio of reactants TEOS/Dioxane/ H2O is 3:12:4 during the sol-gel process. The maximum doping concentration of dyes is the result of dyes dispersing into nanoporous silica, which supported by Infrared Spectroscopy (IR) and X-ray diffraction (XRD) technology. So this sol-gel preparation can enrich the inorganic luminescent materials at a simple style, especially for PL materials or electroluminescent (EL) materials in thin films state.

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“…11 BBOT has been studied as a key material for blue organic light-emitting diodes (OLEDs). 12 There has been a report on the incorporation of BBOT into a glassy silica matrix, 13 but there has so far been no report on BBOT-encapsulated silica particles.…”

Section: Introductionmentioning

confidence: 99%

Screening of a Model for the Distribution of Dye in Dye-Encapsulated Silica Through the Gradual Etching of the Outermost Silica Layer Using Hydrofluoric Acid

Wi¹,

Lee²,

Soon-Ock³

et al. 2011

J. Nanosci. Nanotech.

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Monodispersed spherical silica particles emitting blue light were prepared by incorporating 2,5-bis(5-tert-butyl-2-benzoxazolyl)thiophene (BBOT) into a silica matrix. The morphological and photoluminescent properties were investigated to confirm the proper incorporation of BBOT into the silica matrix, using an electron microscope and a fluorescence spectrometer. Four possible models representing the distribution of the dye molecules in a dye-encapsulated silica particle were proposed. To analyze the distribution of the BBOT dye in the BBOT-encapsulated silica, the fluorescent emission intensity was measured while reducing the particle diameter by etching the outermost silica layer with hydrofluoric acid with 0-0.5 wt.% concentrations. The distribution of BBOT in a silica particle was investigated based on the relationship between the changes in particle diameter and the changes in emission intensity. The emission intensity of the BBOT-encapsulated silica particle oscillated with the decreasing particle diameter. This result supported the multilayered model. Information regarding the distribution of the dye in the silica matrix will provide valuable information for understanding the formation mechanism of dye-encapsulated silica.

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Optical properties of BBOT-doped silica films prepared via sol–gel processing

Cited by 5 publications

References 9 publications

Photophysical, Electrochemical and Crystallographic Investigations of the Fluorophore 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene

Photophysical, Electrochemical and Crystallographic Investigations of the Fluorophore 2,5-Bis(5-tert-butyl-benzoxazol-2-yl)thiophene

Preparation and Photoluminescence of Red, Green and Blue Fluorescent Dyes Co-Doped Nanoporous Silica by a Sol-Gel Method

Screening of a Model for the Distribution of Dye in Dye-Encapsulated Silica Through the Gradual Etching of the Outermost Silica Layer Using Hydrofluoric Acid

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