A compound comprising a first ligand L.sub.A of Formula I, ##STR00001##
is disclosed. In the structure of Formula I, ring A is a 5-membered or 6-membered carbocyclic or heterocyclic ring; Z.sup.1-Z.sup.4 are each independently C or N; at least two consecutive Z.sup.1-Z.sup.4 are C, and are fused to a structure of Formula II ##STR00002##
or Formula III ##STR00003##
Y.sup.1; Y.sup.1 and Y.sup.2 are each independently O, S, Se, CRR′, SiRR′, or GeRR′; each R.sup.A, R.sup.B, R.sup.C, R, and R′ is a hydrogen or a substituent; and any two substituents may be joined or fused together to form a ring. In the compound, L.sub.A is complexed to a metal M by the dashed lines in Formula I to form a five-membered chelate ring, and M has an atomic weight greater than 40. Organic light emitting devices and consumer products containing the compounds are also disclosed.

A compound is disclosed that is selected from the group consisting of a structure having Formula I ##STR00001##
and a structure having Formula II ##STR00002##

A light emitting diode of an embodiment includes a first electrode, a second electrode, and at least one functional layer between the first electrode and the second electrode, wherein the at least one functional layer includes at least one selected from among a polycyclic compound represented by Formula 1 and a compound represented by Formula E-1.

##STR00001##

According to an aspect of the present disclosure, a compound having a metal planar tetradentate coordination configuration is disclosed. In the compounds, the metal M is Pt or Pd; the four coordinating atoms are Z.sup.1, Z.sup.2, Z.sup.3, and Z.sup.4 and are each selected from N, C, and O. The compound includes a substituent R, and atoms M, Z.sup.1, Z.sup.2, Z.sup.3, and Z.sup.4 are used to define a first plane that passes through the metal M and is positioned to have a minimum sum of shortest distances with Z.sup.1, Z.sup.2, Z.sup.3, and Z.sup.4. At least one non-hydrogen atom in R falls within a distal circle of a cylinder extending perpendicular to the first plane, where the distal circle of the cylinder is a height h from the base circle and the height h ranges from 3.3 Å to 4.8 Å.

A compound having the following formula ##STR00001##
Formula I, is disclosed. The compound is useful as an emitter in OLED applications.

A light emitting element that includes a first electrode, a second electrode, and an emission layer between the first electrode and the second electrode is provided. The emission layer includes a polycyclic compound represented by Formula 1. The light emitting element shows a high emission efficiency and long-life characteristics.

##STR00001##

A light emitting element includes a first electrode, a second electrode, and an emission layer between the first electrode and the second electrode and includes a compound represented by Formula 1 below, thereby exhibiting a long service life characteristic.

##STR00001##

A display device includes a sacrificial layer positioned between an encapsulation layer and a light-emitting element that includes a first compound that is the same as a first compound of a light-emitting layer of the light-emitting element, thereby protecting the light-emitting element from an outgas of the encapsulation layer to prevent the generation of dark spots.

Embodiments provide an organometallic compound, a light-emitting device including the organometallic compound, and an electronic apparatus including the light-emitting device. The light-emitting device includes a first electrode, a second electrode facing the first electrode, an interlayer between the first electrode and the second electrode and including an emission layer, and the organometallic compound, which is represented by Formula 1.

##STR00001##

The description of Formula 1 is provided in the specification.

A light-emitting device includes an electron transport region including a first electron transport layer and a second electron transport layer. The first electron transport layer includes a first compound, the second electron transport layer includes a second compound, the first compound includes a pyrimidine group, the second compound includes a triazine group, and an absolute value of a lowest unoccupied molecular orbital (LUMO) energy of the first compound (E.sub.LUMO_E1) is less than an absolute value of a LUMO energy of the second compound (E.sub.LUMO_E2). An electronic apparatus including the light-emitting device.