Light-emitting device, light-emitting apparatus, electronic device, and lighting device
A light-emitting device including an EL layer including a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in this order from the anode side is provided. The first layer contains a first organic compound and a second organic compound. The light-emitting layer contains a sixth organic compound. The fourth layer contains a seventh organic compound. The first organic compound exhibits an electron-accepting property with respect to the second organic compound. A HOMO level of the second organic compound is higher than or equal to −5.7 eV and lower than or equal to −5.2 eV. A HOMO level of the third organic compound is equal to or deeper than the HOMO level of the second organic compound. A difference between the HOMO levels of the second organic compound and the third organic compound is less than or equal to 0.2 eV.
1 . A light-emitting device comprising:
an anode;
a cathode; and
an EL layer between the anode and the cathode,
wherein the EL layer comprises a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in this order from an anode side,
wherein the first layer is in contact with the anode,
wherein the first layer comprises a first organic compound and a second organic compound,
wherein the second layer comprises a third organic compound,
wherein the third layer comprises a fourth organic compound,
wherein the light-emitting layer comprises a fifth organic compound and a sixth organic compound,
wherein the fourth layer comprises a seventh organic compound,
wherein the first organic compound exhibits an electron-accepting property with respect to the second organic compound,
wherein the second organic compound and the third organic compound are the same substance,
wherein the fifth organic compound is an emission center substance,
wherein the sixth organic compound has a heterocyclic skeleton,
wherein a HOMO level of the second organic compound is higher than or equal to −5.7 eV and lower than or equal to −5.2 eV,
wherein electron mobility of the seventh organic compound when a square root of electric field strength [V/cm] is 600 is higher than or equal to 1×10 −7 cm 2 /Vs and lower than or equal to 5 ×10 −5 cm 2 /Vs,
wherein a HOMO level of the fourth organic compound is deeper than a HOMO level of the third organic compound,
wherein a difference between the HOMO level of the third organic compound and the HOMO level of the fourth organic compound is less than or equal to 0.2 eV,
wherein a difference between the HOMO level of the fourth organic compound and a HOMO level of the sixth organic compound is less than 0.2 eV, and
wherein the fourth organic compound is a compound having an aromatic amine skeleton having a substituent that includes a dibenzofuran ring, and a nitrogen directly bonded to an aromatic group in the aromatic amine skeleton is not in a carbazolyl group.
2 . The light-emitting device according to claim 1 ,
wherein the second organic compound has a first hole-transport skeleton,
wherein the third organic compound has a second hole-transport skeleton,
wherein the fourth organic compound has a third hole-transport skeleton, and
wherein each of the first hole-transport skeleton, the second hole-transport skeleton, and the third hole-transport skeleton is independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
3 . The light-emitting device according to claim 1 ,
wherein the sixth organic compound further has an anthracene skeleton.
4 . The light-emitting device according to claim 1 , wherein the second organic compound has a dibenzofuran skeleton.
5 . The light-emitting device according to claim 1 , wherein the seventh organic compound has a quinoxaline skeleton.
6 . The light-emitting device according to claim 1 , wherein the fifth organic compound is a blue fluorescent material.
7 . A light-emitting apparatus comprising:
the light-emitting device according to claim 1 ; and
a transistor, or a substrate.
8 . A light-emitting device comprising:
an anode;
a cathode; and
an EL layer between the anode and the cathode,
wherein the EL layer comprises a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in this order from an anode side,
wherein the first layer is in contact with the anode,
wherein the first layer comprises a first organic compound and a second organic compound,
wherein the second layer comprises a third organic compound,
wherein the third layer comprises a fourth organic compound,
wherein the light-emitting layer comprises a fifth organic compound and a sixth organic compound,
wherein the fourth layer comprises a seventh organic compound,
wherein the first organic compound exhibits an electron-accepting property with respect to the second organic compound,
wherein the second organic compound and the third organic compound are the same substance,
wherein the fifth organic compound is an emission center substance,
wherein the sixth organic compound has a heterocyclic skeleton,
wherein a HOMO level of the second organic compound is higher than or equal to −5.7 eV and lower than or equal to −5.2 eV,
wherein a LUMO level of the sixth organic compound is shallower than a LUMO level of the seventh organic compound,
wherein a difference between the LUMO level of the sixth organic compound and the LUMO level of the seventh organic compound is greater than or equal to 0.1 eV and less than or equal to 0.3 eV,
wherein a HOMO level of the fourth organic compound is deeper than a HOMO level of the third organic compound,
wherein a difference between the HOMO level of the third organic compound and the HOMO level of the fourth organic compound is less than or equal to 0.2 eV,
wherein a difference between the HOMO level of the fourth organic compound and a HOMO level of the sixth organic compound is less than 0.2 eV, and
wherein the fourth organic compound is a compound having an aromatic amine skeleton having a substituent that includes a dibenzofuran ring, and a nitrogen directly bonded to an aromatic group in the aromatic amine skeleton is not in a carbazolyl group.
9 . The light-emitting device according to claim 8 ,
wherein the second organic compound has a first hole-transport skeleton,
wherein the third organic compound has a second hole-transport skeleton,
wherein the fourth organic compound has a third hole-transport skeleton, and
wherein each of the first hole-transport skeleton, the second hole-transport skeleton, and the third hole-transport skeleton is independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
10 . The light-emitting device according to claim 8 ,
wherein the sixth organic compound further has an anthracene skeleton.
11 . The light-emitting device according to claim 8 , wherein the second organic compound has a dibenzofuran skeleton.
12 . The light-emitting device according to claim 8 , wherein the seventh organic compound has a quinoxaline skeleton.
13 . The light-emitting device according to claim 8 , wherein the fifth organic compound is a blue fluorescent material.
14 . A light-emitting apparatus comprising:
the light-emitting device according to claim 8 ; and
a transistor, or a substrate.
15 . A light-emitting device comprising:
an anode;
a cathode; and
an EL layer between the anode and the cathode,
wherein the EL layer comprises a first layer, a second layer, a third layer, a light-emitting layer, and a fourth layer in this order from an anode side,
wherein the first layer is in contact with the anode,
wherein the first layer comprises a first organic compound and a second organic compound,
wherein the second layer comprises a third organic compound,
wherein the third layer comprises a fourth organic compound,
wherein the light-emitting layer comprises a fifth organic compound and a sixth organic compound,
wherein the fourth layer comprises a seventh organic compound,
wherein the first organic compound exhibits an electron-accepting property with respect to the second organic compound,
wherein the second organic compound and the third organic compound are the same substance,
wherein the fifth organic compound is an emission center substance,
wherein the sixth organic compound has a heterocyclic skeleton,
wherein a HOMO level of the second organic compound is higher than or equal to −5.7 eV and lower than or equal to −5.2 eV,
wherein the seventh organic compound is a x-electron deficient heteroaromatic compound comprising a triazine skeleton,
wherein a LUMO level of the sixth organic compound is shallower than a LUMO level of the seventh organic compound,
wherein a difference between the LUMO level of the sixth organic compound and the LUMO level of the seventh organic compound is greater than or equal to 0.1 eV and less than or equal to 0.3 eV,
wherein a HOMO level of the fourth organic compound is deeper than a HOMO level of the third organic compound,
wherein a difference between the HOMO level of the third organic compound and the HOMO level of the fourth organic compound is less than or equal to 0.2 eV,
wherein a difference between the HOMO level of the fourth organic compound and a HOMO level of the sixth organic compound is less than 0.2 eV, and
wherein the fourth organic compound is a compound having an aromatic amine skeleton having a substituent that includes a dibenzofuran ring, and a nitrogen directly bonded to an aromatic group in the aromatic amine skeleton is not in a carbazolyl group.
16 . The light-emitting device according to claim 15 ,
wherein the second organic compound has a first hole-transport skeleton,
wherein the third organic compound has a second hole-transport skeleton,
wherein the fourth organic compound has a third hole-transport skeleton, and
wherein each of the first hole-transport skeleton, the second hole-transport skeleton, and the third hole-transport skeleton is independently any one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
17 . The light-emitting device according to claim 15 ,
wherein the sixth organic compound further has an anthracene skeleton.
18 . The light-emitting device according to claim 15 , wherein a difference between the HOMO level of the third organic compound and a HOMO level of the fourth organic compound is less than or equal to 0.2 eV.
19 . The light-emitting device according to claim 15 , wherein the second organic compound has a dibenzofuran skeleton.
20 . The light-emitting device according to claim 15 , wherein the seventh organic compound has a quinoxaline skeleton.
21 . The light-emitting device according to claim 15 , wherein the fifth organic compound is a blue fluorescent material.
22 . A light-emitting apparatus comprising:
the light-emitting device according to claim 15 ; and
a transistor, or a substrate.
23 . An electronic device comprising:
the light-emitting device according to claim 1 ; and
a sensor, an operation button, a speaker, or a microphone.
24 . An electronic device comprising:
the light-emitting device according to claim 8 ; and
a sensor, an operation button, a speaker, or a microphone.
25 . An electronic device comprising:
the light-emitting device according to claim 15 ; and
a sensor, an operation button, a speaker, or a microphone.
26 . A lighting device comprising:
the light-emitting device according to claim 1 ; and
a housing.
27 . A lighting device comprising:
the light-emitting device according to claim 8 ; and
a housing.
28 . A lighting device comprising:
the light-emitting device according to claim 15 ; and
a housing.