COLL 88 |
| We present the first measurement of the buried surface electronic states of the conjugated polymer poly[2-methoxy, 5-ethyl (2'-hexyloxy) para-phenylenevinylene] (MEH-PPV) using two dimensional (2D) IR-visible sum frequency generation (SFG). By scanning the frequencies of both incident IR and visible beams, SFG electronic spectra were obtained to study the surface electronic transitions associated with the C=C stretching of benzene rings located at the backbone of MEH-PPV. Theoretical analysis based on an oligomer model was employed to estimate the conjugation length distributions of MEH-PPV at interfaces. Assuming a Gaussian conjugation length distribution, it was found that the conjugation length distribution at the MEH-PPV/solid interface is centered at 5.8 monomer units. Similar surface effects were also observed at the air/polymer interface with a slightly shorter average conjugation length of 5.1 monomer units. |
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Interfacial Electron Transfer and Solar Energy Conversion: From Molecules to Nanomaterials
8:20 AM-12:00 PM, Monday, April 7, 2008 Morial Convention Center -- Rm. 226, Oral
Division of Colloid & Surface Chemistry |