TECHNICAL FIELD

The present application is a national phase entry under 35 U.S.C. § 371 of International Application No. PCT/KR2016/010092 filed Sep. 8, 2016, published in Korean, which claims priority from Korean Patent Application No. 10-2015-01127783 filed on Sep. 9, 2015, all of which are incorporated herein by reference.

The present specification relates to an organoluminescent device.

BACKGROUND ART

An organic light emission phenomenon generally refers to a phenomenon converting electrical energy to light energy using an organic material. An organoluminescent device using an organic light emission phenomenon normally has a structure including an anode, a cathode, and an organic material layer therebetween. Herein, the organic material layer is often formed in a multilayer structure formed with different materials in order to increase efficiency and stability of the organoluminescent device, and for example, may be formed with a hole injection layer, a hole transfer layer, a light emitting layer, an electron transfer layer, an electron injection layer and the like. When a voltage is applied between the two electrodes in such an organoluminescent device structure, holes and electrons are injected to the organic material layer from the anode and the cathode, respectively, and when the injected holes and electrons meet, excitons are formed, and light emits when these excitons fall back to the ground state.

As displays using an organoluminescent device become to have large areas, solving problems of efficiency or lifespan has been required. Efficiency and lifespan, driving voltage and the like are related to each other, and as efficiency increases, driving voltage relatively decreases, and while driving voltage decreases, organic material crystallization caused by Joule heating produced during the driving becomes less resultantly leading to a lifespan increase.

Light efficiency of an organoluminescent device is commonly divided into internal luminescnet efficiency and external luminescent efficiency. Internal luminescnet efficiency relates to how efficiently excitons are produced in organic layers provided between a first electrode and a second electrode (that is, between an anode and a cathode) such as a hole transfer layer, a light emitting layer and an electron transfer layer, and light conversion is accomplished. Meanwhile, external luminescent efficiency (hereinafter, also referred to as “light coupling efficiency”) indicates efficiency of light, which is produced in organic layers, extracted outside an organoluminescent device, and even when high light conversion efficiency is obtained in the organic layers (that is, even when internal luminescnet efficiency is high), overall light efficiency of the organoluminescent device is low when external luminescent efficiency is low.

Recently, organoluminescent devices having a top-emission structure emitting from the top using metals having large work function in an anode are being used, and in luminescent devices having a top-emission structure, a semi-transparent electrode such as LiF/Al/Ag, Ca/Mg and LiF/MgAg is used in a cathode. When light emitting to a light emitting layer enters into other layers in such organoluminescent devices, only a part of the emitting light may be used since the light is total-reflected at an interface between the light emitting layer and the other layers when the light enters at a certain angle or higher.

Accordingly, in order to enhance light coupling efficiency, organoluminescent devices in which a capping layer having a high refractive index is installed on an outer side of a semi-transparent electrode having a low refractive index have been proposed, and as a material of the capping layer, materials having a high refractive index, and having excellent thin film stability or durability have been required.

PRIOR ART DOCUMENTS

Patent Documents

Korean Patent Application Laid-Open Publication No. 2014-0145370

DISCLOSURE

Technical Problem

The present specification describes an organoluminescent device. The present disclosure is particularly directed to providing an organoluminescent device including a capping layer having high refractive index and heat resistance for improving light coupling efficiency of the organoluminescent device.

Technical Solution

One embodiment of the present specification provides an organoluminescent device including a first electrode; a second electrode; one or more organic material layers disposed between the first electrode and the second electrode; and a capping layer provided on, a surface opposite to a surface facing the organic material layers of surfaces of the first electrode and the second electrode, wherein the capping layer includes a compound represented by the following Chemical Formula 1.



In Chemical Formula 1,

X is O or S,

R1 is represented by -(L1)p-A1,

L1 is a direct bond; a substituted or unsubstituted arylene group; or a substituted or unsubstituted heteroarylene group,

p is an integer of 0 to 10,

when p is 2 or greater, L is are the same as or different from each other,

A1 is a substituted or unsubstituted amine group; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heterocyclic group,

R2 to R5 are the same as or different from each other, and each independently represented by -(L2)q-A2, or adjacent groups bond to each other to form a substituted or unsubstituted ring,

L2 is a direct bond; a substituted or unsubstituted arylene group; or a substituted or unsubstituted heteroarylene group,

q is an integer of 0 to 10,

when q is 2 or greater, L2s are the same as or different from each other, and

A2 is hydrogen; deuterium; a substituted or unsubstituted aryl group; or a substituted or unsubstituted heterocyclic group.

Advantageous Effects

Compounds described in the present specification can be used as a material of an organic material layer of an organoluminescent device. Compounds according to at least one embodiment are capable of enhancing efficiency, low driving voltage and/or enhancing lifespan properties in an organoluminescent device. Particularly, light emission efficiency and color purity can be significantly improved in an organoluminescent device using compounds described in the present specification as a capping layer.

