Organic electroluminescent element

Abstract

An organic EL device includes a pair of electrodes and an organic compound layer between pair of electrodes. The organic compound layer includes an emitting layer including a first material, a second material and a third material, in which singlet energy EgS(H) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy a specific relationship.

1 . An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
 singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy a relationship of numerical formulae (1) and (2) below,   a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,   the second material is a compound having a fused aromatic hydrocarbon group having 10 to 30 ring carbon atoms or a fused aromatic heterocyclic group having 8 to 30 ring atoms, and   the third material is a fluorescent material,
     EgS ( H 1)> EgS ( D )  (1)
 
     EgS ( H 2)> EgS ( D )  (2)
 
   Δ ST ( H 1)= EgS ( H 1)− Eg   77K ( H 1)<0.3[ eV ]  (3).
 
   
     
     
         2 . The organic electroluminescence device according to  claim 1 , wherein
 the difference ΔST(H1) between the singlet energy EgS(H1) of the first material and the energy gap Eg 77K (H) at 77K of the first material satisfies a relationship of a numerical formula (4) below,
   Δ ST ( H 1)= EgS ( H 1)− Eg   77K ( H 1)<0.2[ eV ]  (4).
 
   
     
     
         3 . The organic electroluminescence device according to  claim 1 , wherein
 an energy gap Eg 77K (H2) at 77K of the second material and an energy gap Eg 77K (D) at 77K of the third material satisfy a relationship of a numerical formula (5) below,
     Eg   77K ( H 2)< Eg   77K ( D )  (5).
 
   
     
     
         4 . The organic electroluminescence device according to  claim 1 , wherein
 the energy gap Eg 77K (H1) at 77K of the first host material and an energy gap Eg 77K (H2) at 77K of the second material satisfy a relationship of a numerical formula (6) below,
     Eg   77K ( H 1)− Eg   77K ( H 2)>0.5[ eV ]  (6).
 
   
     
     
         5 . The organic electroluminescence device according to  claim 1 , wherein
 the energy gap Eg 7K (H1) at 77K of the first host material and an energy gap Eg 77K (D) at 77K of the third material satisfy a relationship of a numerical formula (7) below,
     Eg   77K ( H 1)− Eg   77K ( D )>0.5[eV]  (7).
 
   
     
     
         6 . The organic electroluminescence device according to  claim 1 , wherein
 the organic electroluminescence device exhibits a delayed fluorescence ratio larger than 37.5%.   
     
     
         7 . The organic electroluminescence device according to  claim 1 , wherein
 the organic electroluminescence device exhibits a residual intensity ratio larger than 36.0% after an elapse of 1 μs after voltage removal in a transitional EL measurement.   
     
     
         8 . The organic electroluminescence device according to  claim 1 , wherein
 a half bandwidth of a photoluminescence spectrum of the first material is 50 nm or more.   
     
     
         9 . The organic electroluminescence device according to  claim 1 , wherein
 an emission peak wavelength of the third material is in a range of 500 nm to 600 nm.   
     
     
         10 . (canceled) 
     
     
         11 . The organic electroluminescence device according to  claim 1 , wherein
 the first material is selected from the group consisting of a carbazole derivative, a biscarbazole derivative, an indolocarbazole derivative, an acridine derivative, an oxazine derivative, a pyrazine derivative, a pyrimidine derivative, a triazine derivative, a dibenzofuran derivative, and a dibenzothiophene derivative, the derivatives each optionally having a substituent.   
     
     
         12 . The organic electroluminescence device according to  claim 11 , wherein
 the substituent of each of the derivatives for the first material is selected from the group consisting of an aryl group having 6 to 40 carbon atoms, a heterocyclic group having 2 to 40 carbon atoms, a trialkylsilyl group, dialkylarylsilyl group, an alkyldiarylsilyl group, a triarylsilyl group, a fluorine atom, and a cyano group.   
     
     
         13 . The organic electroluminescence device according to  claim 11 , wherein
 the substituent of each of the derivatives for the first material is selected from the group consisting of an aryl group having 6 to 40 carbon atoms.   
     
     
         14 . The organic electroluminescence device according to  claim 1 , wherein
 the first material is selected from the group consisting of a carbazole derivative, a dibenzofuran derivative, and a dibenzothiophene derivative, each of the derivatives optionally having a substituent.   
     
     
         15 . The organic electroluminescence device according to  claim 14 , wherein
 the substituent of each of the derivatives for the first material is selected from the group consisting of an aryl group having 6 to 40 carbon atoms, a heterocyclic group having 2 to 40 carbon atoms, a trialkylsilyl group, dialkylarylsilyl group, an alkyldiarylsilyl group, a triarylsilyl group, a fluorine atom, and a cyano group.   
     
     
         16 . The organic electroluminescence device according to  claim 14 , wherein
 the substituent of each of the derivatives for the first material is selected from the group consisting of an aryl group having 6 to 40 carbon atoms.   
     
     
         17 . The organic electroluminescence device according to  claim 1 , wherein
 the first material is a compound comprising bonding with a linking group between at least one selected from a carbazole structure, a biscarbazole structure, an indolocarbazole structure, and an acridine structure and at least one selected from an oxazine structure, a pyrazine structure, a pyrimidine structure, a triazine structure, and a dibenzofuran structure, and   the linking group is a single bond, a phenylene structure or metabiphenylene structure.   
     
     
         18 . The organic electroluminescence device according to  claim 11 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         19 . The organic electroluminescence device according to  claim 12 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         20 . The organic electroluminescence device according to  claim 13 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         21 . The organic electroluminescence device according to  claim 14 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         22 . The organic electroluminescence device according to  claim 15 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         23 . The organic electroluminescence device according to  claim 16 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         24 . The organic electroluminescence device according to  claim 17 , wherein
 the third material is a naphthalene derivative, an anthracene derivative, a pyrene derivative, a chrysene derivative, a fluoranthene derivative, an indenoperylene derivative, a pyrromethene-boron complex compound, a compound having a pyrromethene skeleton or a metal complex thereof, a diketopyrolopyrrol derivative, or a perylene derivative.   
     
     
         25 . An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
 singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy relationships of numerical formulae (1) and (2) below,   a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,   the energy gap Eg 77K (H1) at 77K of the first material and an energy gap Eg 77K (D) at 77K of the third material satisfy a relationship of a numerical formula (7) below,   the third material is a fluorescent material, and   the first material is selected from the group consisting of a carbazole derivative, a biscarbazole derivative, an indolocarbazole derivative, an acridine derivative, an oxazine derivative, a pyrazine derivative, a pyrimidine derivative, a triazine derivative, a dibenzofuran derivative, and a dibenzothiophene derivative, these derivatives optionally have a substituent,
     EgS ( H 1)> EgS ( D )  (1)
 
     EgS ( H 2)> EgS ( D )  (2)
 
   Δ ST ( H 1)= EgS ( H 1)− Eg   77K ( H 1)<0.3[ eV ]  (3)
 
     Eg   77K ( H 1)− Eg   77K ( D )>0.5[ eV ]  (7).
 
   
     
     
         26 . An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
 singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy relationships of numerical formulae (1) and (2) below,   a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,   the energy gap Eg 77K (H1) at 77K of the first material is greater than an energy gap Eg 77K (D) at 77K of the third material,   the third material is a fluorescent material, and   the first material is selected from the group consisting of a carbazole derivative, a biscarbazole derivative, an indolocarbazole derivative, an acridine derivative, an oxazine derivative, a pyrazine derivative, a pyrimidine derivative, a triazine derivative, a dibenzofuran derivative, and a dibenzothiophene derivative, these derivatives optionally have a substituent,
     EgS ( H 1)> EgS ( D )  (1)
 
     EgS ( H 2)> EgS ( D )  (2)
 
   Δ ST ( H 1)= EgS ( H 1)− Eg   77K ( H 1)<0.3[ eV ]  (3)
 
   
     
     
         27 . An organic electroluminescence device comprising a pair of electrodes and an organic compound layer therebetween, the organic compound layer comprising an emitting layer comprising: a first material; a second material; and a third material, wherein
 singlet energy EgS(H1) of the first material, singlet energy EgS(H2) of the second material, and singlet energy EgS(D) of the third material satisfy relationships of numerical formulae (1) and (2) below,   the singlet energy EgS(H1) of the first material and the singlet energy EgS(H2) of the second material satisfy a relationship of numerical formula (8) below,   a difference ΔST(H1) between the singlet energy EgS(H1) of the first material and an energy gap Eg 77K (H1) at 77K of the first material satisfies a relationship of a numerical formula (3) below,   the third material is a fluorescent material, and   the first material is selected from the group consisting of a carbazole derivative, a biscarbazole derivative, an indolocarbazole derivative, an acridine derivative, an oxazine derivative, a pyrazine derivative, a pyrimidine derivative, a triazine derivative, a dibenzofuran derivative, and a dibenzothiophene derivative, each of the derivatives optionally having a substituent,
     EgS ( H 1)> EgS ( D )  (1)
 
     EgS ( H 2)> EgS ( D )  (2)
 
   Δ ST ( H 1)= EgS ( H 1)− Eg   77K ( H 1)<0.3[ eV ]  (3)
 
     EgS ( H 2)≥ EgS ( H 1)  (8).