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

A light-emitting device comprising:

• a first electrode;
• a second electrode;
• a first layer;
• a second layer;
• and
• a third layer,
• wherein the first layer is interposed between the first electrode and the second electrode,
• wherein the second layer is interposed between the second electrode and the first layer,
• wherein the third layer is interposed between the second layer and the first layer,
• wherein the first layer comprises a first light-emitting material and a first host material,
• wherein the first light-emitting material has an emission spectrum having a peak at a wavelength λ1,
• wherein the first host material formed into a film has an ordinary refractive index n1 at the wavelength λ1,
• wherein the second layer comprises a second light-emitting material and a second host material,
• wherein the second light-emitting material has an emission spectrum having a peak at a wavelength λ2,
• wherein the second host material formed into a film has an ordinary refractive index n2 at the wavelength λ2,
• wherein the third layer has an ordinary refractive index n31 which is lower than the ordinary refractive index n1 at the wavelength λ1, and
• wherein the third layer has an ordinary refractive index n32 which is lower than the ordinary refractive index n2 at the wavelength λ2.