Blue-Emitting Nanocrystals, Microcrystals, and Highly Oriented Nanofibers Prepared by Reprecipitation and Solvent Drop-Casting of 2-Phenyl-naphthoxazoles

Authors

  • Abdelhamid Ghodbane,

    1. Université de Toulouse; ITAV- UMS 3039, F-31106 Toulouse Cedex 1 (France)
    2. CNRS ITAV-UMS 3031 and IMRCP-UMR 5623, F-31106 Toulouse (France)
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  • Jérémy Colléaux,

    1. Université de Toulouse; ITAV- UMS 3039, F-31106 Toulouse Cedex 1 (France)
    2. CNRS ITAV-UMS 3031 and IMRCP-UMR 5623, F-31106 Toulouse (France)
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  • Dr. Nathalie Saffon,

    1. Service commun RX, Institut de Chimie de Toulouse, ICT-FR2599, Université Paul Sabatier, 31062 Toulouse cedex 9 (France)
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  • Prof. Rachid Mahiou,

    1. CNRS-UMR 6296, ICCF, BP 80026, F-63171 Aubière
    2. Clermont Université, Université Blaise Pascal, Institut de Chimie de Clermont-Ferrand, BP 10448, F-63000 Clermont-Ferrand (France)
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  • Dr. Jean-Pierre Galaup,

    1. Laboratoire Aimé Cotton, CNRS-UPR 3321
    2. Université Paris 11, Bât. 505, 91405 Orsay cedex (France)
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  • Dr. Suzanne Fery-Forgues

    Corresponding author
    1. Université de Toulouse; ITAV- UMS 3039, F-31106 Toulouse Cedex 1 (France)
    2. CNRS ITAV-UMS 3031 and IMRCP-UMR 5623, F-31106 Toulouse (France)
    • Université de Toulouse; ITAV- UMS 3039, F-31106 Toulouse Cedex 1 (France)
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Abstract

Three 2-phenyl-naphth[2,3-d]oxazole derivatives, one of them being unsubstituted (1) and the two others bearing a methyl (2) and a tert-butyl group (3) in the para position of the phenyl ring, were prepared. In the crystalline state, all compounds adopted a crossed-stacking mode that favors fluorescence emission. They emitted in the blue region and their photoluminescence quantum yield ranged between 25 and 59 %. The preparation of micro/nanoparticles by simple methods was optimized. By using a solvent-exchange method, the compounds readily gave microcrystals, the size and shape of which closely depend on the nature of the substituent, as well as nanocrystals that measured around 200 nm. The proportion of micro- and nanocrystals was modulated by the experimental conditions and the two populations could be separated by filtration for subsequent use. For unsubstituted compound 1, drop-casting from a solution in tetrahydrofuran spontaneously generated an array of parallel and almost perpendicularly oriented nanofibers that exhibited efficient waveguiding properties. Owing to their robustness, good solid-state optical properties, and to the simplicity of particle preparation, these naphthoxazole derivatives appear as promising candidates for the fabrication of blue-emitting tracers and nanofibers.

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