| Popis: |
A series of sphere-rod shape amphiphiles, in which a (60)fullerene (C60) sphere was connected to the center of an oligofluorene (OF) rod through a rigid linkage (OF-C60), were designed and synthesized. Alkyl chains of various lengths were attached onto the OFs on both sides of the C60 spheres. These compounds, denoted as alkyl-OF-C60, were fully characterized by 1 H NMR, 13 C NMR, and FTIR spec- troscopy and by MALDI-TOF mass spectrometry. The morphologies and structures of their crystals were eluci- dated by wide-angle X-ray diffraction (WAXD) and by electron diffraction in transmission electron microscopy (TEM). Butyl-OF-C60 forms a mono- clinic unit cell (a = 1.86, b = 3.96, c = 2.24 nm; a = g = 908, b = 688; space group P2), octyl-OF-C60 also forms a monoclinic unit cell (a = 2.21, b = 4.06, c = 1.81 nm; a = g = 908, b = 75.58; space group C2m), and dodecanyl-OF- C60 forms a triclinic structure (a = 1.82, b = 4.35, c = 2.26 nm; a = 93.18, b = 94.58, g = 92.78; space group P1). The inequivalent spheres and rods were found to pack into an alternating lay- ered structure of C60 and OF in the crystals, thus resembling a "double- cable" structure. UV/Vis absorption spectroscopy revealed an electron per- turbation between the two individual chromophores (C60 and OF) in their ground states. Fluorescence spectrosco- py exhibited complete fluorescence quenching of their solutions in toluene, thus suggesting an effective energy transfer from OF to C60. Cyclic voltam- metry indicated that the energy-level profiles of C60 and OF remained essen- tially unchanged. This work has broad implications in terms of understanding the self-assembly and molecular pack- ing of conjugated materials in crystals and has potential applications in organ- ic field-effect transistors and bulk het- erojunction solar cells. |
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