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HL: Fachverband Halbleiterphysik

HL 65: Poster: Organic electronics and photovoltaics (CPP; jointly with HL, O)

HL 65.19: Poster

Mittwoch, 13. März 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.