Polymorphism,Fluorescence, and Optoelectronic Properties of a Borazine Derivative |
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Authors: | Dr Simon Kervyn Dr Oliver Fenwick Dr Francesco Di?Stasio Yong Sig Shin Prof Johan Wouters Dr Gianluca Accorsi Dr Silvio Osella Dr David Beljonne Prof Franco Cacialli Prof Davide Bonifazi |
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Institution: | 1. Department of Chemistry and Namur Research College (NARC), University of Namur (UNamur), Rue de Bruxelles 61, Namur, 5000 (Belgium);2. Department of Physics and Astronomy (CMMP Group) and London Centre for Nanotechnology, University College London, Gower Street, London, WC1E 6BT (UK);3. Molecular Photoscience Group, Istituto per la Sintesi Organica e la Fotoreattività (ISOF), Consiglio Nazionale delle Ricerche (CNR), Via P. Gobetti 101, 40129 Bologna (Italy);4. Laboratory for Chemistry of Novel Materials, University of Mons;5. Place du Parc, 20, 7000 Mons (Belgium);6. Department of Chemical and Pharmaceutical Sciences and INSTM UdR Trieste, University of Trieste, Trieste, Piazzale Europa 1, Trieste (Italy) |
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Abstract: | We have prepared a new borazine derivative that bears mesityl substituents at the boron centers and displays exceptional chemical stability. Detailed crystallographic and solid‐state fluorescence characterizations revealed the existence of several polymorphs, each of which showed different emission profiles. In particular, a bathochromic shift is observed when going from the lower‐ to the higher‐density crystal. Computational investigations of the conformational dynamics of borazine 1 in both the gas phase and in the solid state using molecular dynamics (MD) simulations showed that the conformation of the peripheral aryl groups significantly varies when going from an isolated molecule (in which the rings are able to flip over the 90° barrier at RT) to the crystals (in which the rotation is locked by packing effects), thus generating specific nonsymmetric intermolecular interactions in the different polymorphs. To investigate the optoelectronic properties of these materials by fabrication and characterization of light‐emitting diodes (LEDs) and light‐emitting electrochemical cells (LECs), borazine 1 was incorporated as the active material in the emissive layer. The current and radiance versus voltage characteristics, as well as the electroluminescence spectra reported here for the first time are encouraging prospects for the engineering of future borazine‐based devices. |
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Keywords: | boron doping molecular modeling nitrogen polymorphism |
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