Provided is a light-emitting element with high external quantum efficiency and a low drive voltage. The light-emitting element includes a light-emitting layer which contains a phosphorescent compound and a material exhibiting thermally activated delayed fluorescence between a pair of electrodes, wherein a peak of a fluorescence spectrum and/or a peak of a phosphorescence spectrum of the material exhibiting thermally activated delayed fluorescence overlap(s) with a lowest-energy-side absorption band in an absorption spectrum of the phosphorescent compound, and wherein the phosphorescent compound exhibits phosphorescence in the light-emitting layer by voltage application between the pair of electrodes.

Provided is a light-emitting element with high external quantum efficiency and a low drive voltage. The light-emitting element includes a light-emitting layer which contains a phosphorescent compound and a material exhibiting thermally activated delayed fluorescence between a pair of electrodes, wherein a peak of a fluorescence spectrum and/or a peak of a phosphorescence spectrum of the material exhibiting thermally activated delayed fluorescence overlap(s) with a lowest-energy-side absorption band in an absorption spectrum of the phosphorescent compound, and wherein the phosphorescent compound exhibits phosphorescence in the light-emitting layer by voltage application between the pair of electrodes.

An organic molecule that may be used application in optoelectronic devices is disclosed. The organic molecule has a structure of formula 1, wherein R.sup.I, R.sup.II, R.sup.III, R.sup.IV, R.sup.V, R.sup.VI, R.sup.VII, R.sup.A, R.sup.B, R.sup.C, R.sup.D, R.sup.E, R.sup.F, R.sup.G and R.sup.H are independently selected from the group consisting of: hydrogen, deuterium, halogen, C.sub.1-C.sub.12-alkyl, wherein optionally one or more hydrogen atoms are independently substituted by R.sup.5; C.sub.6-C.sub.18-aryl, wherein optionally one or more hydrogen atoms are independently substituted R.sup.5; and C.sub.3-C.sub.15-heteroaryl, wherein optionally one or more hydrogen atoms are independently substituted R.sup.5; optionally, any adjacent two of R.sup.I, R.sup.II, R.sup.III, R.sup.IV, R.sup.V, R.sup.VI, R.sup.VII, R.sup.A, R.sup.B, R.sup.C, R.sup.D, R.sup.E, R.sup.F, R.sup.G and R.sup.H form a monocyclic ring system having 5 to 8 C-atoms, at least R.sup.A and R.sup.B as well as R.sup.C and R.sup.D form a monocyclic ring system having 5 to 8 C-atoms, wherein, optionally, each hydrogen is independently substituted.

##STR00001##

According to the present invention, options for materials for organic devices such as materials for organic EL elements are increased by addition of a cycloalkane, by condensation, to a polycyclic aromatic compound in which a plurality of aromatic rings are linked together by boron atoms, oxygen atoms, and the like. By using a novel cycloalkane-condensed polycyclic aromatic compound as a material for an organic EL element, for example, an organic EL element having excellent emission efficiency and element life is provided.

An organic electroluminescent device and a display apparatus. The organic electroluminescent device includes a first electrode, a second electrode and an organic layer located between the first electrode and the second electrode. The organic layer includes a light-emitting layer. The light-emitting layer contains a host material, a thermally activated delayed fluorescence sensitizer and a fluorescent dye. The energy level relationship between the host material and the thermally activated delayed fluorescence sensitizer is LUMO.sub.host≥LUMO.sub.sensitizer, while HOMO.sub.sensitizer≥HOMO.sub.host.

The present invention relates to a boron hydroxyl-containing organic compound having a structural formula shown in formula I. The present invention also relates to a method for preparing the boron hydroxyl-containing organic compound and use thereof in an organic electronic device, particularly an organic light-emitting diode. The present invention further relates to an organic electronic device, particularly an organic light-emitting diode, including the boron hydroxyl-containing organic compound according to the present invention and use thereof in display and lighting technology. By optimizing the structure of the device and altering the concentration of the boron hydroxyl-containing organic compound in the substrate, the optimal device performance can be achieved so as to produce an OLED device with high efficiency, high brightness and high stability, which provides a better material option for use in full-color display and lighting.

An organic electroluminescent element including an anode and a cathode and including, between the anode and the cathode, at least a first hole transport layer, a second hole transport layer, a blue-light-emitting layer, and an electron transport layer disposed in this order from the anode side, in which at least one of the layers disposed between the first hole transport layer and the electron transport layer includes an arylamine compound represented by general formula (1).

##STR00001##

The present disclosure provides four monocarborane cluster-containing platinum complexes and a preparation method and an OLED application. The monocarborane cluster-containing platinum complex has a general structural formula selected from the group consisting of the following general structural formulas:

##STR00001##

wherein —R.sub.1 is selected from the group consisting of C.sub.4-12 linear alkyl; each R and R.sub.5 are independently any one selected from the group consisting of —CH.sub.3, H, tert-butyl and aryl; aryl is any one selected from the group consisting of phenyl, carbazole

##STR00002##

and aniline

##STR00003##

wherein R.sub.2 is any one selected from the group consisting of methyl, tert-butyl and phenyl; R.sub.3 is any one selected from the group consisting of methyl, tert-butyl and phenyl; n is 1 to 3; X is C element; when the ligand of the general structural formula is triazole, X is N element; —CB.sub.11H.sub.11 is monocarborane with a structure of

##STR00004##

An organic light-emitting device including: a first electrode and a second electrode each having a surface opposite the other; and an intermediate layer disposed between the first electrode and the second electrode, the intermediate layer including a first compound and a second compound, wherein the first compound includes a first silyl group-containing group and at least two carbazole-derived groups, wherein one carbazole-derived group of the at least two carbazole-derived groups is bonded via a N atom to another carbazole-derived group, the second compound includes a second silyl group-containing group, a triazine group, and a carbazole-derived group, and at least one of the first compound or the second compound has a triplet (T.sub.1) energy level of 2.81 eV or more.

An organometallic compound, represented by Formula 1:

##STR00001## wherein M.sub.1 is a transition metal; X.sub.10 is C; X.sub.11 to X.sub.14, X.sub.20, X.sub.30 to X.sub.36, and X.sub.40 are each independently C or N; ring A.sub.20 and ring A.sub.40 are each independently a C.sub.5-C.sub.30 carbocyclic group or a C.sub.1-C.sub.30 heterocyclic group; and R.sub.1 to R.sub.5, R.sub.10, R.sub.20, R.sub.31, R.sub.32, R.sub.40, R.sub.51, R.sub.52, T.sub.1, b10, b20, b31, b32, and b40 are as defined herein.