A compound comprising a first ligand L.sub.A of Formula I,

##STR00001##

is provided. In Formula I, moiety A is a monocyclic ring or a polycyclic fused ring system; K.sup.1 and K.sup.2 are independently a single bond or a linker; Z.sup.1 and Z.sup.2 are C or N; each R.sup.A, R.sup.B, and R.sup.C is hydrogen or a General Substituent; at least one R.sup.B and at least one R.sup.C are not hydrogen or deuterium; L.sub.A is coordinated to a metal M, having an atomic mass of at least 40. Formulations, OLEDs, and consumer products comprising the compound are also provided.

The present invention relates to a novel polycyclic compound employed by an organic layer of an organic light-emitting device, and an organic light-emitting device employing the compound according to the present invention has markedly improved luminous efficiency. According to the present invention, it is possible to achieve a highly efficient organic light-emitting device which can be effectively applied to a variety of display devices.

The present disclosure provides an organic compound represented by general formula [1].

##STR00001##

In formula [1], R.sub.1 to R.sub.22 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, and so forth. Ar is selected from the group consisting of a residue of an aromatic hydrocarbon and a residue of a heterocyclic compound. Q.sub.1 to Q.sub.4 are each independently a direct bond or a linking group. The linking group is selected from the group consisting of C(R.sub.23)(R.sub.24), N(R.sub.25), an oxygen atom, a sulfur atom, a selenium atom, and a tellurium atom. R.sub.23 to R.sub.25 are each independently selected from the group consisting of a hydrogen atom, an alkyl group, and so forth. k, l, m, and n are each 0 or 1.

A polycyclic aromatic compound according to one aspect of the present invention is a compound which, when exposed to excitation light, is observed to emit light having a peak wavelength in the range of 500 nm to 750 nm, has a HOMO level of not more than ?5.7 eV, and emits delayed fluorescence.

An organometallic compound represented by Formula 1:

##STR00001##

wherein, in Formula 1, groups and variables are the same as described in the specification.

Provided is an organic light-emitting device including a first electrode, a second electrode, and an emission layer therebetween, wherein the emission layer includes a compound represented by the following formula:

##STR00001## Wherein X.sub.1 and X.sub.2 are each independently O or S, A.sub.1 is a 6-membered aromatic group or a 6-membered heteroaromatic group, and details of other constituents are provided in the disclosure.

An 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, the organic layer comprising an emission layer comprising the heterocyclic compound of Formula 1 as a host or as a delayed fluorescent dopant. The organic light-emitting device including the heterocyclic compound may have a low driving voltage and excellent maximum quantum efficiency:

##STR00001##

Probes for formaldehyde (FA) including a homoallylamine trigger group attached to a detectable moiety are provided. Aspects of the probes include luminogenic or fluorogenic probes, such as a probe including a quencher in energy-receiving proximity to a fluroophore. Also provided are methods of using the probes for sensitive and bio orthogonal detection of FA in a sample. Aspects of the methods include selectively reacting the probe with the formaldehyde in the sample to a release (e.g., via a 2-aza-Cope rearrangement) a reporter group comprising a detectable moiety. Aspects of the methods detecting formaldehyde in a cell, tissue, organ or fluid in a subject. Also provided are compositions and kits including the subject probes that find use in practicing various embodiments of the subject methods.

A compound that emits fluorescence and delayed fluorescence is provided as a material for an organic electroluminescent device of high efficiency, and an organic photoluminescent device and an organic electroluminescent device of high efficiency and high luminance are provided using this compound. The compound of a general formula (1) having a diazatriphenylene ring structure is used as a constituent material of at least one organic layer in the organic electroluminescent device that includes a pair of electrodes, and one or more organic layers sandwiched between the pair of electrodes. ##STR00001##

Platinum, palladium, and gold complexes suitable for use as phosphorescent emitters or as delayed fluorescent and phosphorescent emitters having one of the following structures: ##STR00001## ##STR00002## ##STR00003##