Light-emitting element, light-emitting device and an electronic device, which include two layers including same light-emitting organic compound

A light emitting element comprising:

• a first electrode;
• a first layer over the first electrode;
• a second layer over and in contact with the first layer;
• a first charge generation layer over the second layer;
• a third layer over the first charge generation layer;
• a fourth layer over and in contact with the third layer;
• and
• a second electrode over the fourth layer,
• wherein the first layer includes a first light-emitting organic compound and a first organic compound having a hole-transporting property,
• wherein the second layer includes the first light-emitting organic compound and a second organic compound having an electron-transporting property,
• wherein the third layer includes a second light-emitting organic compound and a third organic compound having a hole-transporting property,
• wherein the fourth layer includes the second light-emitting organic compound and a fourth organic compound having an electron-transporting property,
• wherein a highest occupied molecular orbital level of the first organic compound is greater than or equal to −6.0 eV and less than or equal to −5.0 eV, and a lowest unoccupied molecular orbital level of the first organic compound is greater than or equal to −3.0 eV and less than or equal to −2.0 eV,
• wherein a highest occupied molecular orbital level of the second organic compound is greater than or equal to −6.0 eV and less than or equal to −5.0 eV, and a lowest unoccupied molecular orbital level of the second organic compound is greater than or equal to −3.0 eV and less than or equal to −2.0 eV,
• wherein a highest occupied molecular orbital level of the third organic compound is greater than or equal to −6.0 eV and less than or equal to −5.0 eV, and a lowest unoccupied molecular orbital level of the third organic compound is greater than or equal to −3.0 eV and less than or equal to −2.0 eV, and
• wherein a highest occupied molecular orbital level of the fourth organic compound is greater than or equal to −6.0 eV and less than or equal to −5.0 eV, and a lowest unoccupied molecular orbital level of the fourth organic compound is greater than or equal to −3.0 eV and less than or equal to −2.0 eV.

A light emitting element comprising:

• a first electrode;
• a first layer over the first electrode;
• a second layer over and in contact with the first layer;
• a first charge generation layer over the second layer;
• a third layer over the first charge generation layer;
• a fourth layer over and in contact with the third layer;
• and
• a second electrode over the fourth layer,
• wherein the first layer includes a first light-emitting organic compound and a first organic compound having a hole-transporting property,
• wherein the second layer includes the first light-emitting organic compound and a second organic compound having an electron-transporting property,
• wherein the third layer includes a second light-emitting organic compound and a third organic compound having a hole-transporting property,
• wherein the fourth layer includes the second light-emitting organic compound and a fourth organic compound having an electron-transporting property, and
• wherein the first organic compound, the second organic compound, the third organic compound, and the fourth organic compound are reversible to an oxidative reaction and a reductive reaction.

A light emitting element comprising:

• a first electrode;
• a first layer over the first electrode;
• a second layer over and in contact with the first layer;
• and
• a second electrode over the second layer,
• wherein the first layer includes a first light-emitting organic compound and a first organic compound having a hole-transporting property, and
• wherein the second layer includes the first light-emitting organic compound and a second organic compound having an electron-transporting property.