Light-emitting element, display device, electronic device, and lighting device

A light-emitting element comprising:

• a pair of electrodes;
• and
• a light-emitting layer between the pair of electrodes,
• wherein the light-emitting layer comprises a first organic compound, a second organic compound, and a guest material,
• wherein the first organic compound emits a thermally activated delayed fluorescence at room temperature,
• wherein the guest material emits fluorescence,
• wherein an oxidation potential of the first organic compound is lower than or equal to an oxidation potential of the second organic compound,
• wherein a reduction potential of the first organic compound is higher than or equal to a reduction potential of the second organic compound,
• wherein a level of a lowest singlet excitation energy of the second organic compound is higher than or equal to a level of a lowest singlet excitation energy of the first organic compound, and
• wherein the second organic compound comprises a π-electron deficient heteroaromatic skeleton and a π-electron rich heteroaromatic skeleton.