Design of efficient thermally activated delayed fluorescence materials for pure blue organic light emitting diodes.

Qisheng Zhang, Jie Li, Katsuyuki Shizu, Shuping Huang, Shuzo Hirata, Hiroshi Miyazaki, Chihaya Adachi

Index: J. Am. Chem. Soc. 134(36) , 14706-9, (2012)

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Abstract

Efficient thermally activated delayed fluorescence (TADF) has been characterized for a carbazole/sulfone derivative in both solutions and doped films. A pure blue organic light emitting diode (OLED) based on this compound demonstrates a very high external quantum efficiency (EQE) of nearly 10% at low current density. Because TADF only occurs in a bipolar system where donor and acceptor centered (3)ππ* states are close to or higher than the triplet intramolecular charge transfer ((3)CT) state, control of the π-conjugation length of both donor and acceptor is considered to be as important as breaking the π-conjugation between them in blue TADF material design.