High Efficiency Nondoped Deep-Blue Organic Light Emitting Devices Based on Imidazole-π-triphenylamine Derivatives

Abstract

High-performance deep-blue emitting phenanthroimidazole derivatives with a structure of donor−linker−acceptor were designed and synthesized. By using different linkers and different linking positions, four deep-blue emitters were obtained and used as emitters or bifunctional hole-transporting emitters in OLEDs. Such devices show low turn-on voltages (as low as 2.8 V), high efficiency (2.63 cd/A, 2.53 lm/W, 3.08%), little efficiency roll-off at high current densities, and stable deepblue emissions with CIE y < 0.10. Performances are among the best comparing to recently reported deep-blue emitting devices with similar structures. The results suggest that the combination of the phenanthroimidazole and the donor−linker− acceptor structure can be an important approach for developing high performance deep-blue emitters in particular for lighting applications.

Efficient Deep Blue Electroluminescence with an External Quantum Efficiency of 6.8% and CIEy < 0.08 Based on a Phenanthroimidazole–Sulfone Hybrid Donor–Acceptor Molecule

“…42,43 Whereas in most cases it is used as the acceptor part and seldom as donor moiety. 44,45 Herein, phenanthroimidazole is selected as the weak donor and sulfone is used as the moderate acceptor. The D/A moieties are linked by a phenyl π bridge and the corresponding symmetric D-π-A-π-D structure molecule PMSO is constructed.…”

Cross polarization effect of donor-acceptor group on a potential single-molecule transistor

“…The D–A structure has been attracting considerable attention for its unique properties, such as asymmetry structures, first hyperpolarizability, and non‐uniform distributions of charge. Thus, the structure has been widely studied for potential organic light emitting devices, semiconductors in thin film transistors, sensitizers in dye‐sensitized solar cells, unimolecular electrical rectifiers, and non‐linear optical materials . Based on the observed higher polarizability, we conjecture that the D–A structure crossed to a conjugated backbone can be used as an important functional unit (a push–pull tuner) in the design of a single‐molecule FET.…”

Current advances in the synthesis and biological potencies of tri- and tetra-substituted 1H-imidazoles

“…Noticeably, certain heterocyclic molecules, such as imidazoles with N1, C2, C4 and C5 positions substituted with different groups, are utilized broadly as emitting layers in OLEDs for efficient blue [214][215][216] and white light applications [217]. Imidazole-substituted isoquinoline derivatives as π-conjugated compounds, and especially compounds with a phenanthrene moiety, served as a single-emitting component for emitting a nearly "pure" white light having stable CIE coordinates under a variety of driving voltages.…”