Organoelectroluminescent Element, and Light Emission Device, Display Device, and Illumination Device in which Said Organoelectroluminescent Element is Used

Abstract

An organoelectroluminescent element which can satisfy both a high external quantum efficiency and high power efficiency at the same time, which has on a substrate an anode, a first intermediate organic layer composed of at least one organic layer, a light-emitting layer, a second intermediate organic layer composed of at least one organic layer, and a cathode in this order, and in which light is extracted from the aforementioned anode side, wherein the aforementioned light-emitting layer contains a light-emitting material that is oriented in the horizontal direction with the substrate, the order parameter of the aforementioned light-emitting material in the aforementioned light-emitting layer is at least 0.7, and the relationship between the thickness T1 (nm) of the aforementioned first intermediate organic layer and the thickness T2 (nm) of the aforementioned second intermediate organic layer is such that 1.1<T1/T2<4.0 and also such that 20 nm<T2<80 nm.

1 . An organoelectroluminescent element which has on a substrate an anode, a first intermediate organic layer composed of at least one organic layer, a light-emitting layer, a second intermediate organic layer composed of at least one organic layer, and a cathode in this order and in which light is extracted from said anode side, wherein
 said light-emitting layer contains a light-emitting material that is oriented in a horizontal direction with the substrate, the order parameter of said light-emitting material in said light-emitting layer is at least 0.7, and   the relationship between thickness T1 (nm) of said first intermediate organic layer and thickness T2 (nm) of said second intermediate organic layer is such that 1.1<T1/T2<4.0 and also such that 20 nm<T2<80 nm.   
     
     
         2 . The organoelectroluminescent element according to  claim 1 , wherein said light-emitting material is a platinum complex, a pyrene derivative, or a π-conjugated compound expressed by General Formula R-1 below: 
       
         
           
           
               
               
           
         
         wherein each of Ar 1  to Ar 3  independently represents a divalent C 6  to C 30  aromatic hydrocarbon group, each of Ar 4  to Ar 7  independently represents a C 6  to C 30  aromatic hydrocarbon group, the two aromatic hydrocarbon groups constituting Ar 4  and Ar 5  may bond via a direct bond or a substituent to form a condensed heterocycle with the N replaced by Ar 4  and A 5 , and the two aromatic hydrocarbon groups constituting Ar 6  and Ar 7  may bond via a direct bond or a substituent to form a condensed heterocycle with the N replaced by Ar 6  and Ar 7 ; each of L 1  and L 2  independently represents a vinylene group or an acetylene group; and each of l, m, n, o, and p independently represents an integer from 0 to 6, but one of l, n, and p is not 0. 
       
     
     
         3 . The organoelectroluminescent element according to  claim 1 , wherein said light-emitting layer further contains a host material, and this host material is a triphenylene derivative. 
     
     
         4 . The organoelectroluminescent element according to  claim 1 , wherein the maximum emission wavelength of said light-emitting material is 600 to 700 nm, and the relationship between the thickness T1 (nm) of said first intermediate organic layer and the thickness T2 (nm) of said second intermediate organic layer is such that 1.2<T1/T2<4.0 and also such that 30 nm<T2<80 nm. 
     
     
         5 . The organoelectroluminescent element according to  claim 1 , wherein the maximum emission wavelength of said light-emitting material is 400 to 500 nm, and the relationship between the thickness T1 (nm) of said first intermediate organic layer and the thickness T2 (nm) of said second intermediate organic layer is such that 1.1<T1/T2<3.0 and also such that 20 nm<T2<70 nm. 
     
     
         6 . The organoelectroluminescent element according to  claim 1 , wherein a light extraction layer is formed on said substrate. 
     
     
         7 . The organoelectroluminescent element according to  claim 6 , wherein the refractive index of said substrate is at least 1.8. 
     
     
         8 . A light emission device in which the organoelectroluminescent element according to  claim 1  is used. 
     
     
         9 . A display device in which the organoelectroluminescent element according to  claim 1  is used. 
     
     
         10 . An illumination device in which the organoelectroluminescent element according to  claim 1  is used.