Regensburg 2016 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 92: Postersession DS/HL

HL 92.21: Poster

Donnerstag, 10. März 2016, 16:00–19:00, Poster A

Improved color stability of white OLEDs with tandem structure and new host material — •Yuan Liu^1,2, Zuo-Quan Jiang¹, and Liang-Sheng Liao¹ — ¹Institute of Functional Nano & Soft Materials, Soochow University, 215123 Suzhou, China; — ²Institut für Angewandte Photophysik, Technische Universität Dresden, 01062 Dresden, Germany;

Tandem structures can improve the efficiency and lifetime of organic light-emitting diodes (OLEDs) simultaneously. More importantly, this is also an effective strategy to reduce the color shift with increasing current density in white OLEDs. High performance tandem OLEDs require highly efficient emitting units along with an efficient charge generation layer. To improve the performance of single emitting unit, two novel host materials SF2BCz and SF3BCz which combine spirobifluorene and carbazole units via meta- and para-bonding are designed for phosphorescent OLEDs (PhOLEDs). The meta-linkage of spirobifluorene enables SF3BCz to possess high triplet energy, suitable energy levels, and good thermal stability. Blue PhOLEDs featuring SF3BCz as a host show high performance and low efficiency roll-off, with an efficiency of 41.4 cd/A (18.0%, 39.8 lm/W) at 100 cd/m2 and 39.7 cd/A (17.2%, 29.8 lm/W) at 1000 cd/m2. In addition, SF3BCz is adopted as a universal host for tandem white OLEDs, achieving an external quantum efficiency of 40% and a color stable emission spectrum.[1]

References: [1] Y. Liu, L. Cui, X. Shi, Q. Li, Z. Jiang and L. Liao, J. Mater. Chem. C, 2014, 2, 8736.