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Published on: May 29, 2018
Cove-Edged Hexa-peri-hexabenzo-bis-peri-octacene: Molecular Conformations and Amplified Spontaneous Emission
Yanwei Gu1, Victor Vega-Mayoral2, Saül Garcia-Orrit2
1Synthetic Chemistry, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128, Mainz, Germany.
Abstract:
The bottom-up synthesis of an unprecedentedly large cove-edged nanographene, hexa-peri-hexabenzo-bis-peri-octacene (HBPO), is reported in this work. Chiral high-performance liquid chromatography and density functional theory (DFT) calculations revealed multiple conformations in solution. Two different molecular conformations, "waggling" and "butterfly", were found in crystals by X-ray crystallography, and the selectivity of conformations could be tuned by solvents. The optoelectronic properties of HBPO were investigated by UV/Vis absorption and fluorescence spectroscopies, cyclic voltammetry, and DFT calculations. The contorted geometry and branched alkyl groups suppress the aggregation of HBPO in solution, leading to a high fluorescence quantum yield of 79 %. The optical-gain properties were explored through transient absorption and amplified spontaneous emission spectroscopies, which enrich the choices of edge structures for potential applications in laser cavities.
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