Dresden 2003 – wissenschaftliches Programm

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CPP: Chemische Physik und Polymerphysik

CPP 20: POSTER A

CPP 20.60: Poster

Montag, 24. März 2003, 19:00–21:00, ZEU/250

MePTCDI fluorescence lifetime shortening via electron-hole pair generation in semiconductor — •Eugenio Lunedei, Helmut Port, and Hans Christoph Wolf — 3. Physikalisches Institut, Universität Stuttgart

The electronically excited state lifetime of MePTCDI (N,N’-dimethylperylene-3,4:9,10-bis(dicarboximide)) has been measured in–situ at T = 10 K by picosecond time-resolved fluorescence techniques as a function of molecule-substrate distance d from MoS₂ (Molybdenum Disulphide) and Si(111):H (H–terminated Silicon) semiconductors. In both cases a strong fluorescence lifetime reduction is observed in short distance range (d=5-100Å). Such a lifetime shortening is quantitatively described in terms of excitation transfer from electronically excited molecule to the substrate through the creation of electron-hole pairs in the solid by the high-wave-vector components of molecular near field. The different distance dependence in fluorescence lifetime observed on the two substrates is discussed in relation to their electronic band structure.