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

A light-emitting element comprising:

• a guest material;
• and
• a host material,
• wherein the host material comprises any of a pyrimidine skeleton, a pyridazine skeleton, and a triazine skeleton,
• wherein a LUMO level of the guest material is lower than a LUMO level of the host material,
• wherein an energy difference between the LUMO level of the guest material and a HOMO level of the guest material is larger than an energy difference between the LUMO level of the host material and a HOMO level of the host material,
• wherein the guest material is configured to convert triplet excitation energy into light emission,
• wherein an energy difference between the LUMO level of the guest material and the HOMO level of the host material is larger than or equal to transition energy calculated from an absorption edge of an absorption spectrum of the guest material, and
• wherein the energy difference between the LUMO level of the guest material and the HOMO level of the guest material is larger than the transition energy calculated from the absorption edge of the absorption spectrum of the guest material by 0.4 eV or more.

A light-emitting element comprising:

• a guest material;
• and
• a host material,
• wherein the host material comprises any of a pyrimidine skeleton, a pyridazine skeleton, and a triazine skeleton,
• wherein a LUMO level of the guest material is lower than a LUMO level of the host material,
• wherein an energy difference between the LUMO level of the guest material and a HOMO level of the guest material is larger than an energy difference between the LUMO level of the host material and a HOMO level of the host material,
• wherein the guest material is configured to convert triplet excitation energy into light emission,
• wherein an energy difference between the LUMO level of the guest material and the HOMO level of the host material is larger than or equal to light emission energy of the guest material,
• wherein the energy difference between the LUMO level of the guest material and the HOMO level of the guest material is larger than transition energy calculated from an absorption edge of an absorption spectrum of the guest material by 0.4 eV or more.