- Energy down converting organic fluorophore functionalized mesoporous silica hybrids for monolith-coated light emitting diodes
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The covalent attachment of organic fluorophores in mesoporous silica matrices for usage as energy down converting phosphors without employing inorganic transition or rare earth metals is reported in this article. Triethoxysilylpropyl-substituted derivatives of the blue emitting perylene, green emitting benzofurazane, and red emitting Nile red were synthesized and applied in the synthesis of mesoporous hybrid materials by postsynthetic grafting to commercially available MCM-41. These individually dye-functionalized hybrid materials are mixed in variable ratios to furnish a powder capable of emitting white light with CIE chromaticity coordinates of x = 0.33, y = 0.33 and an external quantum yield of 4.6% upon irradiation at 410 nm. Furthermore, as a proof of concept two different device setups of commercially available UV light emitting diodes, are coated with silica monoliths containing the three triethoxysilylpropyl-substituted fluorophore derivatives. These coatings are able to convert the emitted UV light into light with correlated color temperatures of very cold white (41100 K, 10700 K) as well as a greenish white emission with correlated color temperatures of about 5500 K.
- B?rgardts, Markus,Müller, Thomas J. J.
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supporting information
p. 768 - 778
(2017/06/20)
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- Improved synthesis of 4-amino-7-nitrobenz-2,1,3-oxadiazoles using NBD fluoride (NBD-F)
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The 7-nitrobenz-2,1,3-oxadiazole (NBD) unit is a highly useful fluorescent tag with wide application in biology. Installation of the NBD group typically proceeds via the SNAr reaction between an amine and an NBD halide. Herein, we demonstrate that NBD-F 1 results in significantly higher yields than NBD-Cl 2, and that triethylamine in dimethylformamide at 23 °C overnight is a broadly applicable set of conditions for this reaction. In particular, the highly useful fluorescent carbohydrate 2-NBD-glucosamine (2-NBDG, 3) can now be prepared in 75% yield with NBD-F as compared to 12% with NBD-Cl.
- Jung, Michael E.,Dong, Timothy A.,Cai, Xiaolu
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p. 2533 - 2535
(2011/06/21)
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