Impact Factor:0.0
DOI number:10.1002/adma.202313746
Journal:Advanced Materials
Abstract:In organic light-emitting diode (OLED), achieving high efficiency requires effective triplet exciton confinement by carrier-transporting materials, which typically have higher triplet energy (ET) than the emitter, leading to poor stability. Here, an electron-transporting material (ETM), whose ET is 0.32 eV lower than that ofthe emitter is reported. In devices, it surprisingly exhibits strong confinement effect and generates excellent efficiency. Additionally, the device operational lifetime is 4.9 times longer than the device with a standard ETM, 1,3,5-tri(1-phenyl-1H-benzo[d]imidazol-2-yl) phenyl (whose ET 0.36 eV is higher than the emitter). This anomalous finding is ascribed to the exceptionally long triplet state lifetime (≈0.2 s) ofthe ETM. It is named as long-lifetime triplet exciton reservoir effect. The systematic analysis reveals that the long triplet lifetime ofETM can compensate the requirement for high ET with the help ofendothermic energy transfer. Such combination oflow ET and long lifetime provides equivalent exciton confinement effect and high molecular stability simultaneously. It offers a novel molecular design paradigm for breaking the dilemma between high efficiency and prolonged operational lifetime in OLEDs.
Indexed by:Journal paper
Volume:36
Issue:21
Page Number:2313746
Translation or Not:no
Included Journals:SCI
Links to published journals:https://onlinelibrary.wiley.com/doi/10.1002/adma.202313746
Date of Publication:2024-02-09