On-chain defect emission in electroluminescent polyfluorenes
Abstract
We present time-resolved photoluminescence measurements on a range of poly- and oligofluorenes with different molecular weights in both dilute solution and thin films. The commonly observed parasitic broad green emission band, which has previously been attributed to an excimer, is identified in all solution and film samples and assigned to an on-chain emissive defect. By comparison of the luminescence decay in the solid state at different temperatures it is shown that, at room temperature, intramolecular relaxation is faster in these polyphenylenes than intermolecular exciton diffusion.
- Publication:
-
Applied Physics Letters
- Pub Date:
- June 2002
- DOI:
- 10.1063/1.1486482
- Bibcode:
- 2002ApPhL..80.4489L
- Keywords:
-
- conducting polymers;
- electroluminescence;
- photoluminescence;
- time resolved spectra;
- organic semiconductors;
- polymer films;
- polymer solutions;
- excitons;
- molecular weight;
- defect states;
- Amorphous Materials;
- Conducting Polymers;
- Defects;
- Electroluminescence;
- Excitons;
- Molecular Weight;
- Optical Properties;
- Organic Semiconductors;
- Photoluminescence;
- Thin Films;
- Time Functions;
- Time Measurement;
- 78.55.Kz;
- 78.55.Bq;
- 71.55.Jv;
- 36.20.Cw;
- 78.60.Fi;
- 36.20.Kd;
- 78.47.+p;
- 78.66.Qn;
- Solid-State Physics;
- Solid organic materials;
- Liquids;
- Disordered structures;
- amorphous and glassy solids;
- Molecular weights dispersity;
- Electroluminescence;
- Electronic structure and spectra;
- Time-resolved optical spectroscopies and other ultrafast optical measurements in condensed matter;
- Polymers;
- organic compounds