Light-Emitting Element, Light-Emitting Device, Lighting Device, and Electronic Appliance

A light-emitting element comprising:

• a hole-transport layer between an anode and a cathode;
• and
• a layer containing a light-emitting substance between the anode and the cathode, the layer containing the light-emitting substance being in contact with a cathode side surface of the hole-transport layer,
• wherein the hole-transport layer includes a first organic compound and an anti-reduction substance,
• wherein the LUMO level of the anti-reduction substance is lower than the LUMO level of the first organic compound,
• wherein the layer containing the light-emitting substance includes a second organic compound and the light-emitting substance, and
• wherein the layer containing the light-emitting substance has at least an electron-transport property.

A light-emitting element comprising:

• a hole-transport layer between an anode and a cathode;
• and
• a layer containing a light-emitting substance between the anode and the cathode, the layer containing the light-emitting substance being in contact with a cathode side surface of the hole-transport layer,
• wherein the hole-transport layer includes a first organic compound and an anti-reduction substance,
• wherein the LUMO level of the anti-reduction substance is lower than the LUMO level of the first organic compound,
• wherein the layer containing the light-emitting substance includes a second organic compound and the light-emitting substance, and
• wherein the layer containing the light-emitting substance has a bipolar property.

A light-emitting element comprising:

• a hole-transport layer between an anode and a cathode;
• and
• a layer containing a light-emitting substance between the anode and the cathode, the layer containing the light-emitting substance being in contact with a cathode side surface of the hole-transport layer,
• wherein the hole-transport layer includes a first organic compound and an anti-reduction substance which easily accepts an electron as compared with the first organic compound,
• wherein the LUMO level of the anti-reduction substance is lower than the LUMO level of the first organic compound,
• wherein the layer containing the light-emitting substance has at least an electron-transport property,
• wherein the layer containing the light-emitting substance includes a first light-emitting layer provided on an anode side and a second light-emitting layer provided to be in contact with a cathode side surface of the first light-emitting layer,
• wherein the first light-emitting layer includes a second organic compound as a host material and the light-emitting substance as a guest material,
• wherein the second light-emitting layer includes a third organic compound as a host material and the light-emitting substance as a guest material, and
• wherein the light-emitting substance of the second light-emitting layer has a hole-trapping property.