Light-Emitting Element, Light-Emitting Device, Electronic Device, and Lighting Device
Objects of the present invention are to provide: a light-emitting element having a long lifetime and good emission efficiency and drive voltage. One embodiment of the invention is a light-emitting element including, between an anode and a cathode, at least a stack structure in which a first layer, a second layer, and a light-emitting layer are provided in order from the anode side. The first layer includes a first organic compound and an electron-accepting compound. The second layer includes a second organic compound having a HOMO level differing from the HOMO level of the first organic compound by from −0.2 eV to +0.2 eV. The light-emitting layer includes a third organic compound having a HOMO level differing from the HOMO level of the second organic compound by from −0.2 eV to +0.2 eV and a light-emitting substance having a hole-trapping property with respect to the third organic compound.
1 . (canceled)
2 . A compound comprising:
a furan skeleton to which an aromatic ring is fused,
wherein a HOMO level of the compound is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the compound is used as a host material for an organic EL layer in a fluorescent light-emitting device.
3 . A compound comprising:
a furan skeleton to which two aromatic rings are fused,
wherein a HOMO level of the compound is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the compound is used as a host material for an organic EL layer in a fluorescent light-emitting device.
4 . A compound comprising:
an anthracene skeleton; and
a furan skeleton to which an aromatic ring is fused,
wherein a HOMO level of the compound is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the compound is used as a host material for an organic EL layer in a fluorescent light-emitting device.
5 . A compound comprising:
an anthracene skeleton; and
a furan skeleton to which two aromatic rings are fused,
wherein a HOMO level of the compound is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the compound is used as a host material for an organic EL layer in a fluorescent light-emitting device.
6 . The compound according to claim 2 , wherein the compound is bipolar.
7 . The compound according to claim 3 , wherein the compound is bipolar.
8 . The compound according to claim 4 , wherein the compound is bipolar.
9 . The compound according to claim 5 , wherein the compound is bipolar.
10 . A light-emitting device comprising:
a fluorescent light-emitting layer,
wherein a HOMO level of a host material of the fluorescent light-emitting layer is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the host material comprises a compound comprising a furan skeleton to which an aromatic ring is fused.
11 . A light-emitting device comprising:
a fluorescent light-emitting layer,
wherein a HOMO level of a host material of the fluorescent light-emitting layer is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the host material comprises a compound comprising a furan skeleton to which two aromatic rings are fused.
12 . A light-emitting device comprising:
a fluorescent light-emitting layer,
wherein a HOMO level of a host material of the fluorescent light-emitting layer is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the host material comprises a compound comprising a furan skeleton to which an aromatic ring is fused and an anthracene skeleton.
13 . A light-emitting device comprising:
a fluorescent light-emitting layer,
wherein a HOMO level of a host material of the fluorescent light-emitting layer is greater than or equal to −6.0 eV and less than or equal to −5.7 eV, and
wherein the host material comprises a compound comprising a furan skeleton to which two aromatic rings are fused and an anthracene skeleton.
14 . The light-emitting device according to claim 10 , wherein a light-emitting substance of the fluorescent light-emitting layer comprises an aromatic amine skeleton.
15 . The light-emitting device according to claim 10 ,
wherein the fluorescent light-emitting layer comprises a light-emitting substance, and
wherein a HOMO level of the light-emitting substance is higher than the HOMO level of the compound by 0.3 eV or more.
16 . The light-emitting device according to claim 11 , wherein a light-emitting substance of the fluorescent light-emitting layer comprises an aromatic amine skeleton.
17 . The light-emitting device according to claim 11 ,
wherein the fluorescent light-emitting layer comprises a light-emitting substance, and
wherein a HOMO level of the light-emitting substance is higher than the HOMO level of the compound by 0.3 eV or more.
18 . The light-emitting device according to claim 12 , wherein a light-emitting substance of the fluorescent light-emitting layer comprises an aromatic amine skeleton.
19 . The light-emitting device according to claim 12 ,
wherein the fluorescent light-emitting layer comprises a light-emitting substance, and
wherein a HOMO level of the light-emitting substance is higher than the HOMO level of the compound by 0.3 eV or more.
20 . The light-emitting device according to claim 13 , wherein a light-emitting substance of the fluorescent light-emitting layer comprises an aromatic amine skeleton.
21 . The light-emitting device according to claim 13 ,
wherein the fluorescent light-emitting layer comprises a light-emitting substance, and
wherein a HOMO level of the light-emitting substance is higher than the HOMO level of the compound by 0.3 eV or more.