Light-emitting device, light-emitting apparatus, electronic apparatus, and lighting device

A light-emitting device comprising:

• an anode;
• a cathode;
• and
• an EL layer between the anode and the cathode,
• wherein the EL layer comprises a light-emitting layer and a hole-transport region,
• wherein the hole-transport region is between the anode and the light-emitting layer,
• wherein the hole-transport region comprises a first organic compound,
• wherein the first organic compound is an aromatic monoamine compound,
• wherein when the first organic compound is a deposited film, an ordinary refractive index of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 1.50 and less than or equal to 1.75, and a birefringence Δn of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 0 and less than or equal to 0.04,
• wherein the light-emitting layer comprises a second organic compound, a third organic compound, and a light-emitting substance, and
• wherein the second organic compound and the third organic compound form an exciplex.

A light-emitting device comprising:

• an anode;
• a cathode;
• and
• an EL layer between the anode and the cathode,
• wherein the EL layer comprises a light-emitting layer and a hole-transport region,
• wherein the hole-transport region is between the anode and the light-emitting layer,
• wherein the hole-transport region comprises a first organic compound,
• wherein the first organic compound is an aromatic monoamine compound and comprises at least one of an alkyl group having 3 to 8 carbon atoms and a cycloalkyl group having 6 to 12 carbon atoms,
• wherein when the first organic compound is a deposited film, an ordinary refractive index of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 1.50 and less than or equal to 1.75, and a birefringence Δn of the deposited film with respect to light with a wavelength of 458 nm is greater than or equal to 0 and less than or equal to 0.008,
• wherein the light-emitting layer comprises a second organic compound, a third organic compound, and a light-emitting substance, and
• wherein the second organic compound and the third organic compound form an exciplex.