Berlin 2012 – wissenschaftliches Programm
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DS: Fachverband Dünne Schichten
DS 44: Poster IV: Thin film photovoltaics; Organic electronics and photovoltaics (jointly with CPP, HL, O); Organic thin films; Trends in atomic layer deposition (Focused session)
DS 44.19: Poster
Freitag, 30. März 2012, 09:30–12:00, Poster E
Influence of triplet excitons on the performance and lifetime of polymer-based organic light-emitting diodes — •Oili Pekkola1, Fabian Etzold2, Andrea Gassmann1, Frédéric Laquai2, Christian Melzer1, and Heinz von Segger1 — 1Electronic Materials Department, Institute of Materials Science, Technische Universität Darmstadt, Petersenstr. 23, 64287 Darmstadt, Germany — 2Max Planck Research Group for Organic Optoelectronics, Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
Although large progress has been made in the development of polymer-based organic light-emitting diodes (PLEDs), their lifetime still remains a problematic issue. One of the topics in PLEDs studied to a lesser extent is the influence of the high density of non-emissive triplet excitons on the device lifetime.
In this work, PLEDs with a poly(p-phenylene vinylene) (PPV) derivative are utilized. The influence of triplet excitons on the fatigue of the PLEDs is investigated by increasing their amount in the PPV film. Therefore, PPV singlet excitons are converted to triplets by mixing different concentrations of the triplet sensitizer platinum (II) octaethylporphine ketone (PtOEPK) into the PPV matrix. The increase in the triplet population is characterized by photoluminescence and photoinduced absorption measurements. Both t50 and t90 lifetimes of the diodes are drastically shortened in the presence of PtOEPK, which indicates that the additional triplets might be harmful to the diode stability and lifetime.