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

A light emitting element comprising:

• a glass substrate;
• a first electrode over the glass substrate;
• 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 difference between a highest occupied molecular orbital level of the first organic compound and a highest occupied molecular orbital level of the second organic compound is 0.3 eV or less,
• wherein a difference between a lowest unoccupied molecular orbital level of the first organic compound and a lowest unoccupied molecular orbital level of the second organic compound is 0.3 eV or less,
• wherein a difference between a highest occupied molecular orbital level of the third organic compound and a highest occupied molecular orbital level of the fourth organic compound is 0.3 eV or less, and
• wherein a difference between a lowest unoccupied molecular orbital level of the third organic compound and a lowest unoccupied molecular orbital level of the fourth organic compound is 0.3 eV or less.