| 摘要 |
An organic EL element (1) of the present invention includes an emission layer (5) which is made of a host material having a highest occupied molecular orbital shallower than a highest occupied molecular orbital (8) of an organic light emitting material in the emission layer (5) (|HOMO of host material|<|HOMO of organic light emitting material|) or a host material having a lowest unoccupied molecular orbital deeper than a lowest unoccupied molecular orbital (9) of the organic light emitting material (|LUMO of host material|>|LUMO of organic light emitting material|). This makes it possible to keep the hole mobility and the electron mobility high in the host material of the emission layer (5), and therefore the hole and the electron can be efficiently transported to the emission layer (5). As a result, both the hole and the electron can be confined within the emission layer (5), and therefore the hole becomes more likely to recombine with the electron. On this account, the internal quantum yield rate can be improved, the luminous efficiency can be improved, and a driving voltage can be reduced. |
