The present disclosure relates to an organic electroluminescent compound, and an organic electroluminescent device comprising the same. By comprising the organic electroluminescent compound according to the present disclosure, it is possible to provide an organic electroluminescent device having improved current efficiency and/or lifetime properties.

A light emitting element includes a first electrode, a hole transport region disposed on the first electrode, an emission layer disposed on the hole transport region, an electron transport region disposed on the emission layer, and a second electrode disposed on the electron transport region, wherein the hole transport region includes a first hole transport layer disposed adjacent to the first electrode and including a first amine compound having a first refractive index, a second hole transport layer disposed between the first hole transport layer and the emission layer, and including a second amine compound having a second refractive index greater than the first refractive index, and a third hole transport layer disposed between the second hole transport layer and the emission layer, and including a third amine compound having a third refractive index less than the second refractive index, thereby having high luminous efficiency.

The present invention relates to peptide modifier compounds of Formula (1), or a salt thereof, wherein: a is an integer from 1 to 10, more preferably from 1 to 3; b is an integer from 0 to 7; Z is a terminal group and Y is a bivalent group. Further aspects of the invention relate to intermediates in the preparation of compounds of Formula (1), and the use of compounds of Formula 1 in the synthesis of peptide derivatives. ##STR00001##

Provided is a thermally stable bisphenol composition whose increase in the Hazen color number is suppressed even under higher temperature conditions. A bisphenol composition including an aryl alkyl sulfide or a dialkyl disulfide at 0.1 ppb by mass to 1% by mass with respect to a bisphenol. A bisphenol composition including an aryl alkyl sulfide or a dialkyl disulfide at a predetermined ratio is thermally stable in terms of the Hazen color number, and shows no coloring problem under high temperature conditions. By using such a bisphenol composition, a polycarbonate resin having an excellent color tone can be produced.

The present disclosure relates to an arylamine compound and an organic electroluminescent device. The arylamine compound has a structure represented by Formula (1), and contains N atoms rich in electrons and a number of large conjugated systems, so that the electron mobility and the transition rate can be improved. The device prepared from the arylamine compound has high electrical stability, and device efficiency and long device lifetime.

##STR00001##

Provided are a nitrogen-containing compound, an organic electroluminescent device and an electronic apparatus. The nitrogen-containing compound has a structure as shown in chemical formula 1; Ar.sub.1 and Ar.sub.2 are the same or different, and each is independently selected from a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl; and R.sub.0 is selected from hydrogen, a C1-C6 alkyl, a substituted or unsubstituted C6-C30 aryl, or a substituted or unsubstituted C3-C30 heteroaryl. The nitrogen-containing compound acts as a hole transporting material or a host material of a luminescent layer and can effectively improve the performance of organic electroluminescent devices.

##STR00001##

A group of novel 9H-fluorene derivatives suitable for the preparation of active substances for the treatment of Alzheimer's disease, in particular as multifunctional inhibitors of the BuChE and BACE1 enzymes and beta-amyloid aggregation.

A light emitting element includes a first electrode, a second electrode disposed on the first electrode, and an emission part disposed between the first electrode and the second electrode and including a first emission layer and a second emission layer disposed on the first emission layer, the first emission layer may include a first host, and a first dopant, and the second emission layer may include a hole transport host different from the first host, an electron transport host, and a second dopant. A first hole mobility of the first host may be in a range of about 5.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−3 cm.sup.2/Vs, a second hole mobility of a host mixture including the hole transport host and the electron transport host may be in a range of about 1.0×10.sup.−6 cm.sup.2/Vs to about 1.0×10.sup.−4 cm.sup.2/Vs, and the first hole mobility may be larger than the second hole mobility.

The present invention relates to compounds of formula (1). The compounds are suitable for use in electronic devices, in particular organic electroluminescent devices, comprising these compounds. In some embodiments, the compounds are used as matrix materials for phosphorescent or fluorescent emitters as well as a hole-blocking or electron-transport materials. ##STR00001##

An organic compound having a hole-transport property and a low refractive index is provided. An organic compound represented by General Formula (G1) shown below is provided. In General Formula (G1), Ar.sup.1 represents a substituted or unsubstituted arylene group having 6 to 13 carbon atoms in a ring, n represents an integer of 0 or 1, and Ar.sup.2 represents an aryl group having 6 to 10 carbon atoms in a ring and includes at least one branched-chain or cyclic alkyl group having 3 to 12 carbon atoms. The total number of carbon atoms of the branched-chain or cyclic alkyl group in Ar.sup.2 is more than or equal to 6. R.sup.1 to R.sup.4 each independently represent an alkyl group having 1 to 6 carbon atoms. R.sup.11 to R.sup.14 and R.sup.21 to R.sup.24 each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Any one of R.sup.15 to R.sup.18 and any one of R.sup.25 to R.sup.28 each represent a bond directly bonded to a nitrogen atom, and the others each independently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

##STR00001##