Organic electroluminescent element

An organic electroluminescent device comprising one or more light emitting layers between an anode and a cathode opposite to each other,

• wherein at least one of the light emitting layers contains an organic emission material having a difference between excited singlet energy (S1) and excited triplet energy (T1) (ΔEST) of 0.20 eV or less as a light emitting dopant, a first host selected from the compounds represented by the following general formula (1), and a second host selected from the compounds represented by the following general formula (2);
• and the organic emission material is a boron-containing polycyclic aromatic compound represented by the following general formula (3) or (4):
• wherein X1 represents O, S, or N-Ar1;
• Ar1 independently represents a substituted or unsubstituted monocyclic aromatic hydrocarbon group having 6 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 3 aromatic rings thereof;
• R1 independently represents deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms;
• a and d represent an integer of 0 to 4;
• and b and c represent an integer of 0 to 3,
• wherein X2 independently represents N or C—H, and at least two X2 represent N;
• Ar2 represents a substituted or unsubstituted monocyclic aromatic hydrocarbon group having 6 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 4 aromatic rings thereof;
• R2 independently represents deuterium, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms;
• and e, f, g, and h represent an integer of 0 to 4,
• wherein X3 represents N-Ar3, O, or S, and at least one X3 represents N-Ar3;
• Ar3 independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 aromatic rings thereof;
• R3 independently represents a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms;
• i and j represent an integer of 0 to 4;
• and k represents an integer of 0 to 3,
• wherein X4 represents N-Ar4, O, or S, and at least one X4 represents N-Ar4;
• Ar4 independently represents a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms, or a substituted or unsubstituted linked aromatic group formed by linking 2 to 8 aromatic rings thereof;
• R4 independently represents a cyano group, deuterium, a diarylamino group having 12 to 44 carbon atoms, an aliphatic hydrocarbon group having 1 to 10 carbon atoms, a substituted or unsubstituted aromatic hydrocarbon group having 6 to 18 carbon atoms, or a substituted or unsubstituted aromatic heterocyclic group having 3 to 17 carbon atoms;
• m and n represent an integer of 0 to 4;
• o and p represent an integer of 0 to 3;
• and q represents an integer of 0 to 2, and
• wherein, when the aromatic hydrocarbon group, aromatic heterocyclic group, or linking aromatic group in Ar1, Ar2, Ar3, Ar4, R1, R2, R3, and R4 is substituted, the substituent is an aliphatic hydrocarbon group having 1 to 10 carbon atoms.