Sub-picosecond spectroscopy and pump-probe experiments show Forster energy transfer in blends from larger gap (blue or green-emitting) host polymers poly(2,3-diphenyl-5-hexyl-1,4-phenylenevinylene) (DP6-PPV) or poly[2-(meta-2′-ethylhexoxyphenyl)-1,4-phenylenevinylene) (m-EHOP-PPV) to the smaller gap, red-emitting guest polymer poly(2,5-bis(2′-ethylhexoxy)-1,4-phenylenevinylene) (BEH-PPV). The dynamics of the stimulated emission (SE) and photoinduced absorption (PA) of the blends indicate that 10-20 ps are required for complete energy transfer. Quantitative measurements of energy transfer rates give a Forster interaction range of 3-4 nm, 1.4 times longer than the theoretical values as calculated from the spectral overlap. We attribute this difference to delocalization of the excited state. Insufficient spectral overlap between the emission of the host and absorption of the guest is shown to be the cause for the absence of energy transfer in a blend with poly(2,5-bis(cholestanoxy)-1,4-phenylenevinylene) (BCHA-PPV) as the guest polymer.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Mechanics of Materials
- Mechanical Engineering
- Metals and Alloys
- Materials Chemistry