The present invention provides a photoelectric conversion element having excellent heat resistance. In addition, the present invention provides an optical sensor and an imaging element including the photoelectric conversion element. In addition, the present invention provides a compound applied to the photoelectric conversion element. The photoelectric conversion element according to the embodiment of the present invention including a conductive film, a photoelectric conversion film, and a transparent conductive film, in this order, in which the photoelectric conversion film contains a compound represented by Formula (1) or (2). ##STR00001##

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

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.

Provided is an organic light-emitting device including: an anode; a cathode provided to face the anode; a light-emitting layer provided between the anode and the cathode; a first organic material layer provided between the anode and the light-emitting layer; and a second organic material layer provided between the cathode and the light emitting layer in which each organic material, from among organic materials included in the light-emitting layer and the organic material layers, the band gap energy (E.sub.bg) of each of the organic materials except for a dopant compound is 3 eV or more, the first organic material layer comprises one or more compounds each composed of centrally sp3 carbon, the second organic material layer includes one or more compounds each composed of centrally sp3 carbon, and the first organic material layer and the second organic material layer include three or more compounds each composed of centrally sp3 carbon.

Compounds of formula (1):

##STR00001##

wherein each symbol is as defined in the description, may provide an organic electroluminescence device having a further improved performance.

Provided are: a compound that further improves the capability of an organic EL device, an organic electroluminescent device having a further improved device capability, and an electronic device including the organic electroluminescent device. Precisely provided are: a compound represented by the following formula (1A) or formula (1B) (wherein the symbols are as defined in the description), an organic electroluminescent device containing the compound, and an electronic device including the organic electroluminescent device.

##STR00001##

A compound represented by the following formula (1):

##STR00001##

The R.sup.1 to R.sup.9, L.sup.1 to L.sup.3, and Ar.sup.1 to Ar.sup.2 in the formula (1) are as defined in the description. An organic electroluminescence device contains the compound, and an electronic instrument includes the organic electroluminescence device.

A compound may improve the capability of an organic EL device, and an organic electroluminescent device including such compound may have improved capability and may be included in electronic devices. Such compounds may be of formula (1A) or formula (1B) (wherein the symbols are as defined in the description)

##STR00001##

organic electroluminescent device(s) may contain such compound(s), and electronic device(s) may include such organic electroluminescent device(s).

A photoelectric conversion element includes a base, a first electrode on or above the base, an electron-transporting layer on or above the first electrode, a photoelectric conversion layer on or above the electron-transporting layer, a hole-transporting layer on or above the photoelectric conversion layer, and a second electrode on or above the hole-transporting layer. The photoelectric conversion element has a penetration portion penetrating the electron-transporting layer and the photoelectric conversion layer. The photoelectric conversion element includes, in the penetration portion, a material of the hole-transporting layer and a material of the second electrode.