Regensburg 2013 – scientific programme
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HL: Fachverband Halbleiterphysik
HL 65: Poster: Organic electronics and photovoltaics (CPP; jointly with HL, O)
HL 65.19: Poster
Wednesday, March 13, 2013, 16:30–18:30, Poster C
Brightly Blue and Green Emitting Copper Compounds for Singlet Harvesting in OLEDs — •Markus Leitl1, Fritz-Robert Küchle2, Lars Wesemann2, and Hartmut Yersin1 — 1Institut für Physikalische und Theoretische Chemie, Universität Regensburg, D-93040, Germany — 2Institut für Anorganische Chemie, Universität Tübingen, D-72076, Germany
In this contribution, a series of four Cu(I) complexes is presented. All substances exhibit high emission quantum yields of up to 65 % at relatively short emission decay times of several µ s. The emission wavelength varies from the blue (460 nm) to the green (505 nm). This is induced by defined modifications of the chemical structure. Detailed photophysical investigations reveal that the energy separation Δ E(S1−T1) between the triplet state T1 and the singlet state S1 is small and lies in the range of 500 cm−1. As a consequence, emission at ambient temperature originates dominantly (> 99 %) from the S1 state which is thermally populated from the energetically lower lying T1 state. For this reason, the emission at ambient temperature represents a thermally activated delayed fluorescence (TADF). It is proposed to utilize this property for collecting both singlet and triplet excitons in the lowest excited singlet state for light generation in OLEDs. This effect represents the singlet harvesting mechanism.