| Shape control of symmetric nanocrystals has inspired wide interest in recent years, due to their beauty in symmetry and potential applications in sensors and catalyts and biomedicine. Tremendous efforts have been directed towards developing synthetic capabilities to produce inorganic polydedral crystals with controlled shapes in the form of cube, cuboctahedron, and octahedron. Despite much success in inorganic nanocrystals, preparation and shape control of symmetric micro- or nano-structures of small-molecular organic compounds has not yet been reported, although they may offer great variety and flexibility in molecular design and thus tunability in electronic and optical properties. Herein, we demonstrate, the control synthesis of 2, 5, 8, 11-tetra-tertbutylperylene (TBPe) particles in the shape of cube, truncated cube or rhombic dodecahedron via a simple surfactant-assisted process. We further investigate kinetically controlled growth of new microstuctures fromed at high supersaturation. X-ray absorption near-edge structure (XANES) and X-ray excited optical luminescence (XEOL) have been used to study the optical properties of 2, 5, 8, 11-tetra-butyl-perylene (TBPe) polyhedral crystals with morphology varies from cube to rhombic dodecahedron. Benefit from the high resolution of synchrotron radiation spectroscopy, C 1s toπ* andσ* transitions from different carbon sites in TBPe can be clearly distinguished in the carbon K-edge XANES. XEOL studies reveal that different crystals exhibit multiple emission bands with different branching ratio, attributed to different sample texture and surface state of the crystals. |
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