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Cathodoluminescence characterization of organic semiconductor materials for light emitting device applications

Charakterisierung von organischen Halbleitern mittels Kathodolumineszenz für Leuchtdioden-Anwendungen
: Wellmann, P.J.; Karl, U.; Kleber, S.; Schmitt, H.

Postprint urn:nbn:de:0011-n-874077 (452 KByte PDF)
MD5 Fingerprint: a7dee2bda339449ac57610a9436d6e96
Erstellt am: 22.1.2009

Journal of applied physics 101 (2007), Nr.11, Art. 113704, 6 S.
ISSN: 0021-8979
ISSN: 1089-7550
Zeitschriftenaufsatz, Elektronische Publikation
Fraunhofer IISB ()
cathodoluminescence; organic semiconductor; light emitting device; characterization; triplet harvester material

We report the development of a cathodoluminescence-based characterization technique for the investigation of organic semiconductor materials for organic light emitting device (OLED) applications. While photoluminescence is known to predominantly address singlet exciton excitation and recombination processes, cathodoluminescence is able to simultaneously probe singlet and triplet exciton dynamics which is of importance for electroluminescence. Especially, in the case of the so-called triplet harvester materials, the generation of triplet excitons during cathodoluminescence opens the way for materials characterization without device fabrication. The paper (i) shows how cathodoluminescence can be applied for the characterization of organic semiconductor materials, (ii) points out the general measurement factors, (iii) discusses the special features of cathodoluminescence, electroluminescence as well as photoluminescence spectra, and (iv) outlines the potential of cathodoluminescence by presenting a brief study of a triplet harvester material systems. Main emphasis is put on the presentation of the characterization tool to partly replace the necessity of OLED fabrication. For that reason widely used conjugated polymers and small molecule semiconductor systems have been selected.