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SYOH: Organic and Hybrid Systems for Future Electronics
SYOH 5: Poster
SYOH 5.85: Poster
Donnerstag, 11. März 2004, 18:00–21:00, B
A Spectroscopic Investigation Using Model Oligofluorenes — •Chan Im1, Chunyan Chi1, Panagiotis E. Keivanidis1, Andreas Ziegler1, Sigrud Höger1, Gerhard Wegner1, Jung-Ho Jo2, Ji-Hoon Kang2, and Do-Young Yoon2 — 1Max-Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany — 2Seoul National University, Department of Chemistry, Seoul, South-Korea
Polyfluorene derivatives are very promising electroluminescent materials due to their highly effcient electroluminescence with blue emission color. Unfortunately, there is still a well-known problem that a broad green emission band appears and grows up during the operating of light emitting devices. While many groups have shown that ketonic defects on polymer backbones are mainly responsible for this green band, there are still many questions which should be answered as for the population of these green emissive states. To understand the nature of such ketonic defect states in detail, we have decided to study a model system including a number of oligofluorenes both with and without an embedded ketone unit. After synthesis of highly pure oligofluorenes, delayed fluorescence measurements were performed at various temperatures either as films or as dilute solutions to estimate photoluminescent properties for long lived emission bands, e.g. the green band. Additionally, fast spectroscopy using a streak camera within a time range of nanoseconds was carried out in order to trace blue singlet emission decay behavior. Those detailed spectroscopic results show significantly different photoluminescence behavior between oligofluorenes with various sidechain groups especially in solid state.