A light-emitting device includes a first electrode, a second electrode facing the first electrode, and an interlayer disposed between the first electrode and the second electrode. The emission layer includes a first emission layer and a second emission layer. The first emission layer includes a first compound, and the second emission layer includes a second compound. The first compound includes at least one deuterium (D), and the second compound does not include deuterium. An electronic apparatus including the light-emitting device is also provided.

A light-emitting element having low driving voltage and high emission efficiency is provided. In the light-emitting element, a combination of a guest material and a host material forms an exciplex. The guest material is capable of converting triplet excitation energy into light emission. Light emission from the light-emitting layer includes light emission from the guest material and light emission from the exciplex. The percentage of the light emission from the exciplex to the light emission from the light-emitting layer is greater than 0 percent and less than or equal to 60 percent. The energy after subtracting the energy of light emission from the exciplex from the energy of light emission from the guest material is greater than 0 eV and less than or equal to 0.23 eV.

A light-emitting device and an electronic apparatus including the light-emitting device. The light-emitting device includes: a first electrode; a second electrode facing the first electrode; and an interlayer located between the first electrode and the second electrode, wherein the interlayer includes an emission layer and a hole transport region which is located between the first electrode and the emission layer, the hole transport region includes a hole transport layer and a hole transport auxiliary layer which is located between the hole transport layer and the emission layer, the hole transport layer has a single-layered structure or a multi-layered structure, and a refractive index of the hole transport layer is higher than a refractive index of the hole transport auxiliary layer.

A condensed cyclic compound represented by Formula 1:

##STR00001##

wherein in Formula 1, a1, a2, Ar.sub.1, Ar.sub.2, R.sub.1, and R.sub.2 are the same as described in the specification.

A compound represented by Chemical Formula 1, an organic optoelectronic device including the same, and a display device including the organic optoelectronic device are provided. The structure of the compound represented by Chemical Formula 1 is described in the present specification.

Arrangements for phosphorescent blue emissive materials, layers, and devices are provided. The arrangements include a host having first a triplet energy level of at least 2.8 eV and an absolute difference of not more than 0.3 eV between the first singlet and triplet energy levels, and an emitter that includes an emissive transition metal complex and a first triplet energy level of at least 2.7 eV.

Disclosed are a transition metal complex, a polymer, a mixture, a composition and the use thereof, wherein the transition metal complex has a structure of the general formula as shown in formula (1): ##STR00001##
The transition metal complex has a novel structure, and is an iridium (III) complex comprising rigid cycloalkyl groups. Since this type of auxiliary ligand increases the rigidity and symmetry of a molecule, the rigidity of a molecule is increased relative to a common ligand without the cycloalkyl groups, and as such, the whole complex has better chemical, optical, electrical and thermal stabilities. At the same time, since the modification occurs on the auxiliary ligand, the effect on the wavelength of the luminous maximum peak caused by a main ligand is relatively low, and therefore, a saturated luminous color may be retained. Therefore, the use of the transition metal complex according to the present invention in OLEDs, in particular as a doping material of a luminous layer, can provide a relatively high luminous efficiency and a relatively long lifetime of the device.

An organometallic compound represented by Formula 1: ##STR00001## wherein, in Formula 1, M, X.sub.11, X.sub.12, X.sub.13, X.sub.14, A.sub.11, R.sub.11, R.sub.14, b11, n, L.sub.11, and m are described in the specification.

A light-emitting element having low driving voltage and high emission efficiency is provided. In the light-emitting element, a combination of a guest material and a host material forms an exciplex. The guest material is capable of converting triplet excitation energy into light emission. Light emission from the light-emitting layer includes light emission from the guest material and light emission from the exciplex. The percentage of the light emission from the exciplex to the light emission from the light-emitting layer is greater than 0 percent and less than or equal to 60 percent. The energy after subtracting the energy of light emission from the exciplex from the energy of light emission from the guest material is greater than 0 eV and less than or equal to 0.23 eV.

An organic light-emitting device comprising: a first electrode; a second electrode facing the first electrode; a first emission unit, a second emission unit and a third emission unit between the first electrode and the second electrode; a first charge generation layer between the first emission unit and the second emission unit; and a second charge generation layer between the second emission unit and the third emission unit, wherein the first emission unit comprises a first emission layer, the second emission unit comprises a second emission layer, the third emission unit comprises a third emission layer, and at least one of the first emission unit, the second emission unit and the third emission unit comprises an inorganic buffer layer.