Light-Emitting Element, Light-Emitting Device, and Method for Manufacturing the Same

A light-emitting element comprising:

• a first electrode;
• a second electrode;
• a hole-transport layer between the first electrode and the second electrode;
• an electron-transport layer between the first electrode and the second electrode;
• and
• a light-emitting layer between the hole-transport layer and the electron-transport layer,
• wherein the light-emitting layer comprises:
• a first light-emitting layer comprising a first light-emitting substance and being in contact with the hole-transport layer;
• a second light-emitting layer comprising a second light-emitting substance and being in contact with the first light-emitting layer;
• and
• a third light-emitting layer comprising a third light-emitting substance between the first light-emitting layer and the electron-transport layer,
• wherein the first light-emitting layer and the second light-emitting layer are bipolar, and
• wherein the hole-transport layer comprise a first organic compound and an anti-reducing substance.

A light-emitting element comprising:

• a first electrode;
• a second electrode;
• a hole-transport layer between the first electrode and the second electrode;
• an electron-transport layer between the first electrode and the second electrode;
• and
• a light-emitting layer between the hole-transport layer and the electron-transport layer,
• wherein the light-emitting layer comprises:
• a first light-emitting layer comprising a first light-emitting substance and being in contact with the hole-transport layer;
• and
• a second light-emitting layer comprising a second light-emitting substance and being in contact with the first light-emitting layer,
• wherein the first light-emitting layer and the second light-emitting layer are bipolar, and
• wherein the hole-transport layer comprise a first organic compound and a metal oxide.

A light-emitting element comprising:

• a first electrode;
• a second electrode;
• a hole-transport layer between the first electrode and the second electrode;
• and
• a light-emitting layer between the hole-transport layer and the second electrode,
• wherein the light-emitting layer comprises:
• a first light-emitting layer comprising a first light-emitting substance and being in contact with the hole-transport layer;
• and
• a second light-emitting layer comprising a second light-emitting substance and being in contact with the first light-emitting layer, and
• wherein the hole-transport layer comprise a first organic compound and an anti-reducing substance.