The weak stability of a hole‐transporter upon approaching the anion state is one of the major bottlenecks for developing long‐life organic light‐emitting devices (OLEDs). Therefore, in this study, we developed a series of thermally and electrically stable hole‐transporters that are end‐capped with four dibenzofuran units. These materials exhibit i) high bond dissociation energy (BDE) toward the anion state, ii) a high glass transition temperature (Tg>130 °C), and iii) high triplet energy (ET>2.7 eV), thereby enabling approximately 20 % high external quantum efficiency (EQE) and significantly prolonging the stability of both thermally activated delayed fluorescent (TADF) and phosphorescent OLEDs with an operation lifetime at 50 % (LT50) of 20 000–30 000 h at 1000 cd m−2. In addition, investigating their structure‐property relationship revealed that ionization potential (IP), BDE, and Tg are critical prerequisites for the hole‐transporter to prolong lifetime in OLEDs.
A new entry of nBPhen-based n-type exciplex host partner realizes high efficiency and highly stable deep red phosphorescent organic light-emitting devices with an emission peak wavelength of 670 nm, and maximum external quantum efficiency of 17%.
Anthracene derivatives are one of the most promising blue emitters employed in organic light‐emitting devices (OLEDs) because of their electrochemical and thermal stabilities. However, their high crystallinity owing to their large π‐planar structures severely impedes the progress in the development of solution‐based systems. In this work, we developed two types of highly soluble multifunctional anthracene derivatives terminated with ortho‐biphenyl and triphenylamine moieties and showed high solubility in general organic solvents such as toluene, tetrahydrofuran, and cyclohexanone at high concentrations (>10 mg mL−1), and showed blue emission with a peak wavelength of ∼465 nm and a high photoluminescence quantum yield that ranges up to 81 %. Notably, these emitters are suitable for fabricating both evaporation‐ and solution‐based systems. The evaporation‐based system OLED achieved a high external quantum efficiency (EQE) of 5.4 %. While the solution‐processed system realized 4.8 %, exhibiting the best performance among the anthracene‐based solution‐processed OLEDs so far.
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