An organic electroluminescence device includes: an anode; an emitting layer; and a cathode, the emitting layer containing a first material, a second material and a third material, the first material being a fluorescent material, the second material being a delayed fluorescent material, the third material having a singlet energy larger than a singlet energy of the second material.

A metal tetradentate complex is disclosed in which an imidazole moiety is used as a linker in the ligand. The complex is useful as an emitter or other functional roles in an OLED device.

An organic light-emitting device including a predetermined host and a thermally activated delayed fluorescence emitter.

Provided are compounds, formulations comprising compounds, and devices that utilize compounds, where the devices include a substrate, a first electrode, an organic emissive layer comprising an organic emissive material disposed over the first electrode. The device includes an enhancement layer, comprising a plasmonic material exhibiting surface plasmon resonance that non-radiatively couples to the organic emissive material and transfers excited state energy from the organic emissive material to the non-radiative mode of surface plasmon polaritons. The enhancement layer is provided no more than a threshold distance away from the organic emissive layer, where the organic emissive material has a total non-radiative decay rate constant and a total radiative decay rate constant due to the presence of the enhancement layer. At least one of the organic emissive material and the organic emissive layer has a vertical dipole ratio (VDR) value of equal or greater than 0.33.

Provided is a blue light emitting organic EL device having high emission efficiency and a long lifetime.

An organic electroluminescent device comprising one or more light emitting layers between an anode and a cathode opposite to each other, wherein at least one of the light emitting layers contains an organic emission material having a difference between excited singlet energy (S1) and excited triplet energy (T1) (ΔEST) of 0.20 eV or less as a light emitting dopant, a first host selected from the compounds represented by the following general formula (1), and a second host selected from the compounds represented by the following general formula (2).

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A display apparatus that includes an OLED (organic light-emitting device) substrate including a first blue light-emitting unit, a green light-emitting unit, and a second blue light-emitting unit which are stacked; and a color controller provided on the OLED substrate to adjust color of a light generated from the OLED substrate.

A nitrogen-containing compound is represented by the following Formula 1 ##STR00001##
where B.sub.1 to B.sub.4 are each independently N or CR.sub.1, A.sub.1 is an electron accepting group, L1 and R1 are further defined, and D is an electron donating group represented by the following Formula 2 ##STR00002##
X is Si or Ge and Y1, Y2, R2, R3, n and m are further defined. An organic electroluminescence device includes the nitrogen-containing compound.

The present invention relates to organic light emitting elements, comprising thermally activated delayed fluorescence (TADF) emitters and/or hosts of formula ##STR00001##
which have a sufficiently small energy gap between S.sub.1 and T.sub.1 (ΔE.sub.ST) to enable up-conversion of the triplet exciton from T.sub.1 to S.sub.1. The organic light emitting elements show high electroluminescent efficiency.

An organic electroluminescent device and a display apparatus. The organic electroluminescent device includes a first electrode, a second electrode and an organic layer disposed between the first electrode and the second electrode, where the organic layer includes an emission layer (EML), the EML includes a host material, a thermally activated delayed fluorescence (TADF) sensitizer and a fluorescent dye, and the fluorescent dye is selected from a compound represented by Formula (1).

A light emitting device includes a first electrode, a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, an electron transport region disposed on the emission layer, and a second electrode disposed on the electron transport region. The emission layer includes a fused polycyclic compound represented by Formula 1.

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