Provided is an organic light emitting device including an anode; a cathode; a light emitting layer between the anode and the cathode; a first organic material layer between the light emitting layer and the anode; and a second organic material layer between the light emitting layer and the cathode, wherein the first organic material layer comprises a compound of Chemical Formula 1, the light emitting layer comprises a compound of Chemical Formula 2, the second organic material layer comprises a compound of Chemical Formula 3, and Chemical Formula 1 and Chemical Formula 3 satisfy one or more of <Equation 1> to <Equation 3>:

##STR00001##

|E.sub.L1|<E.sub.L3|  <Equation 1>

E.sub.s1>E.sub.s3  <Equation 2>

E.sub.T1>E.sub.T3  <Equation 3>

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 novel light-emitting element is provided. A light-emitting element with a long lifetime is provided. A light-emitting element with high emission efficiency is provided. In the light-emitting element, an EL layer includes a hole-injection layer, a first hole-transport layer, a second hole-transport layer, a third hole-transport layer, a light-emitting layer, a first electron-transport layer, and a second electron-transport layer in this order; the hole-injection layer includes an organic acceptor; the LUMO level of the host material is higher than that of the first electron-transport layer; the LUMO level of the second electron-transport layer is higher than that of the first electron-transport layer; the host material is a substance including a condensed aromatic ring skeleton; and the first and second electron-transport layers each include a substance having a heteroaromatic ring skeleton.

A compound having a formula: ##STR00001##
Formula I useful as emitters in OLEDs is disclosed.

An organic electroluminescence device includes a first electrode, an organic layer disposed on the first electrode, and a second electrode disposed on the organic layer. The organic layer includes an organometallic compound represented by Formula 1 below. ##STR00001##
where R.sub.1 to R.sub.4, X.sub.1 to X.sub.4, Ar.sub.1 to Ar.sub.3, M, Q, m1 to m4, and n are as defined in the specification.

Provided is a compound of Chemical Formula 1: ##STR00001## where A and B each independently is a substituted or unsubstituted aryl group, a substituted or unsubstituted monocyclic or dicyclic heteroaryl group, a substituted or unsubstituted dibenzofuran group, a substituted or unsubstituted benzonaphthofuran group, a substituted or unsubstituted dibenzothiophene group, a substituted or unsubstituted benzonaphthothiophene group, a substituted or unsubstituted phenoxazine group, a substituted or unsubstituted phenothiazine group, a substituted or unsubstituted phenanthroline group, a substituted or unsubstituted benzoquinoline group, a substituted or unsubstituted arylamine group, a substituted or unsubstituted silyl group, or a substituted or unsubstituted phosphine oxide group, or one of the following substituents: ##STR00002## and an organic light emitting device including the same.

An organic electroluminescence device of an embodiment includes a first electrode, a second electrode and a plurality of organic layers disposed between the first electrode and the second electrode, in which at least one of the organic layers includes a polycyclic compound including a plurality of electron donors and an electron acceptor connecting the electron donors, at least one of the electron donors is a condensed ring including a borepine core, and the electron acceptor includes a phenyl group including, as a substituent, at least one cyano group or a heterocycle including at least one nitrogen atom, or a heteroaryl group including an oxygen atom or a sulfur atom for forming a ring, thereby achieving improved emission efficiency.

Provided are an organic-light-emitting device and a display apparatus including the same. The organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and including at least one light-emitting unit, wherein the at least one light-emitting unit includes: an emission layer; and a hole transport region between the first electrode and the emission layer and including a first hole transport (HT) layer, the emission layer includes a host, the first HT layer includes a first compound, a minimum bond dissociation energy (BDE.sub.1HT) of the first compound is larger than a triplet energy (T.sub.1,host) of the host, and a minimum bond dissociation energy (BDE.sub.host) of the host is larger than the triplet energy (T.sub.1,host) of the host.

A display device includes a display panel having first and second regions with the second region having a higher resolution than the first region and an electronic module under the first region. The display panel includes first and second emission layers in a first sub-region of the first region with the second emission layer being spaced apart from the first emission layer. The first emission layer has a first light-emitting portion and a second light-emitting portion adjacent to the first light-emitting portion in a first direction, and the second emission layer has a third light-emitting portion and a fourth light-emitting portion adjacent to the third light-emitting portion in the first direction. The first light-emitting portion is inclined from the second light-emitting portion toward a lower surface of the display panel, and the fourth light-emitting portion is inclined from the third light-emitting portion toward an upper surface of the display panel.

A display panel includes: a substrate including an opening area, a display area, and a non-display area, the display area surrounding the opening area, and the non-display area being between the opening area and the display area; a plurality of display elements at the display area of the substrate, each of the display elements including a pixel electrode, an emission layer on the pixel electrode, and an opposite electrode on the emission layer; a thin-film encapsulation layer covering the plurality of display elements; a dam at the non-display area, and protruding from a top surface of a first insulating layer; and a recess between the opening area and the dam, and recessed in a depth direction of the first insulating layer. A lateral wall of the dam meets a first lateral wall from among lateral walls of the recess, the first lateral wall being adjacent to the display area.