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

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.

Devices having multiple multicomponent emissive layers are provided, where each multicomponent EML includes at least three components. Each of the components in each EML is a host material or an emitter. The devices have improved color stability and relatively high luminance.

A light emitting element includes a pair of electrodes and first and second organic layers between the pair of electrodes. The second organic layer is adjacent to the first organic layer. The first organic layer includes a first organic material. The second organic layer includes a second organic material. The second organic layer includes a first region and a second region. The first region is in contact with the first organic layer and includes the first organic material.

A quantum dot light-emitting diode substrate having a bonding layer and a method of preparing the same are provided. The quantum dot light-emitting diode substrate including a plurality of sub-pixel light-emitting regions, wherein each of the sub-pixel light-emitting regions includes a light-emitting layer including a bonding layer and a quantum dot bonded to the bonding layer. The quantum dot light-emitting diode substrate can be prepared with high resolution by a convenient process, and is suitable for mass production.

Provided are a heterocyclic compound and an organic light-emitting device including the same. The heterocyclic compound includes a fluoro-containing cyclic group. The heterocyclic compound does not include a carbazole group, a dibenzofuran group, a dibenzothiophene group, and/or a triphenylene group. 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 an organic layer, the organic layer including an emission layer and at least one of the heterocyclic compound.

A novel display apparatus that is highly convenient, useful, or reliable is provided. The display apparatus includes a first electrode, a second electrode, a first unit, a second unit, and a first intermediate layer; the first unit is located between the second electrode and the first electrode; and the first unit contains a first light-emitting material EM1. The second unit is located between the second electrode and the first unit and contains a second light-emitting material EM2. The first intermediate layer is located between the second unit and the first unit. The first intermediate layer includes a first layer and a second layer; the first layer is located between the second unit and the second layer; the first layer contains an organic compound having a halogen group or a cyano group or a transition metal oxide; and the second layer contains a first organic compound AM2 having an electron-accepting property, a second organic compound DM having an electron-donating property, and a third organic compound BM having basicity.