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Cover Picture: Phys. Status Solidi RRL 2‐3/2009
Publication year - 2009
Publication title -
physica status solidi (rrl) – rapid research letters
Language(s) - English
Resource type - Reports
SCImago Journal Rank - 0.786
H-Index - 68
eISSN - 1862-6270
pISSN - 1862-6254
DOI - 10.1002/pssr.200990002
Subject(s) - annihilation , oled , cover (algebra) , phosphorescence , brightness , excited state , quenching (fluorescence) , optoelectronics , physics , computer science , materials science , nanotechnology , fluorescence , atomic physics , quantum mechanics , optics , engineering , mechanical engineering , layer (electronics)
During the last years the research field of organic semi‐conductors, in particular light emitting diodes (OLEDs), has rapidly developed. Many of the targeted applications, such as flat and highly efficient white light sources, demand OLEDs to be operated at high brightness levels. This is accompanied by bimolecular, non‐linear quenching effects reducing the device efficiency. Especially phosphorescent dyes are facing very high excitation densities owing to their naturally longer excited state lifetime in the range of microseconds. In the Rapid Research Letter on p. 67ff. Sebastian Reineke et al. address host–guest triplet–triplet annihilation (TTA), which is an additional, unwanted quenching pathway for highly excited triplet states. The authors observe this host–guest TTA directly and are able to deduce its contribution to the overall bimolecular annihilation at high brightness from the change in photoluminescence transients as a function of excitation power.