Luminescence device, and display device including same

1. A luminescence device comprising:

a first electrode;

a first emission portion on the first electrode;

a second electrode on the first emission portion and having a first surface facing the first electrode and a second surface facing oppositely away from the first surface;

a capping layer on the second surface of the second electrode and comprising a metal atom and a metal halide compound; and

an auxiliary capping layer on the capping layer and comprising the metal atom and the metal halide compound and not comprising an organic compound,

wherein the metal atom contains at least one of a lanthanide metal, a transition metal, or a post-transition metal, and the metal halide compound is formed by combining an alkali metal atom and a halogen atom,

wherein a volume ratio of the metal atom and the metal halide compound is 1:2, 1:4, or 2:1,

wherein the second electrode is between the capping layer and the first electrode,

wherein the capping layer is between the auxiliary capping layer and the second electrode, and

wherein the auxiliary capping layer is different in refractive index from that of the capping layer.

2. The luminescence device of claim 1 , wherein the capping layer does not comprise an organic compound.

3. The luminescence device of claim 1 , wherein the halogen atom contains at least one of CI, Br, or I.

4. The luminescence device of claim 1 , wherein the metal halide compound contains at least one of LiI, NaI, KI, RbI, or CsI.

5. The luminescence device of claim 1 , wherein the metal atom and the metal halide compound are bonded to each other to form a ternary compound.

6. The luminescence device of claim 5 , wherein the ternary compound is represented by Formula 1 below:

X n Y m Z q   [Formula 1]

wherein in Formula 1,

X and Y are each independently an alkali metal, a transition metal, or a post-transition metal,

Z is a halogen atom, and

n, m, and q are each independently an integer of 1 to 5.

7. The luminescence device of claim 6 ,

wherein in Formula 1,

X is an alkali metal,

Y is a transition metal or a post-transition metal,

n and m are each 1, and

q is 3.

8. The luminescence device of claim 5 , wherein the ternary compound contains at least one of KYbI 3 , RbYbI 3 , CsYbI 3 , NaYbI 3 , LiYbI 3 , RbSmI 3 , CsSmI 3 , KSmI 3 , NaSmI 3 , or LiSmI 3 .

9. The luminescence device of claim 1 , further comprising a thin film encapsulation layer directly on the capping layer.

10. The luminescence device of claim 1 ,

wherein the first emission portion comprises an emission layer, and

wherein

the emission layer is an organic emission layer comprising an organic compound, or

the emission layer is a quantum dot emission layer comprising a quantum dot.

11. The luminescence device of claim 1 , further comprising a second emission portion,

wherein the first emission portion comprises: a first hole transport region; a first emission layer on the first hole transport region; and a first electron transport region on the first emission layer, and

the second emission portion comprises: a second hole transport region; a second emission layer on the second hole transport region; and a second electron transport region on the second emission layer.

12. The luminescence device of claim 1 , wherein the capping layer has a refractive index of 1.4-2.0 in a wavelength range of 280-780 nm.

13. A luminescence device comprising:

a first electrode;

a hole transport region on the first electrode;

an emission layer on the hole transport region;

an electron transport region on the emission layer;

a second electrode on the electron transport region and having a first surface facing the first electrode and a second surface facing oppositely away from the first surface;

a capping layer on the second surface of the second electrode and comprising a metal atom and a metal halide compound; and

an auxiliary capping layer on the capping layer and comprising the metal atom and the metal halide compound and not comprising an organic compound,

wherein the metal atom contains at least one of a lanthanide metal, a transition metal, or a post-transition metal and the metal halide compound is formed by combining an alkali metal atom and a halogen atom,

wherein a volume ratio of the metal atom and the metal halide compound is 1:2, 1:4, or 2:1,

wherein the second electrode is between the capping layer and the first electrode,

wherein the capping layer is between the auxiliary capping layer and the second electrode, and

wherein the auxiliary capping layer is different in refractive index from that of the capping layer.

14. The luminescence device of claim 13 , wherein the metal atom contains at least one of Eu, Sm, or Yb.

15. The luminescence device of claim 13 , wherein the metal halide compound is formed by combining an alkali metal atom and an iodine atom.

16. A display device comprising:

a thin film transistor; and

a luminescence device on the thin film transistor,

wherein the luminescence device includes:

a first electrode,

a hole transport region on the first electrode,

an emission layer on the hole transport region,

an electron transport region on the emission layer,

a second electrode on the electron transport region and having a first surface facing the first electrode and a second surface facing oppositely away from the first surface,

a capping layer on the second surface of the second electrode and comprising a metal atom and a metal halide compound, and

an auxiliary capping layer on the capping layer and comprising the metal atom and the metal halide compound and not comprising an organic compound,

wherein the metal atom contains at least one of a lanthanide metal, a transition metal, or a post-transition metal and the metal halide compound is formed by combining an alkali metal atom and a halogen atom,

wherein a volume ratio of the metal atom and the metal halide compound is 1:2, 1:4, or 2:1,

wherein the second electrode is between the capping layer and the first electrode,

wherein the capping layer is between the auxiliary capping layer and the second electrode, and

wherein the auxiliary capping layer is different in refractive index from that of the capping layer.

17. The display device of claim 16 ,

wherein the metal atom contains at least one of Eu, Sm, or Yb, and

the metal halide compound contains at least one of LiI, NaI, KI, RbI, or CsI.

18. The display device of claim 16 , wherein the capping layer comprises at least one of KYbI 3 , RbYbI 3 , CsYbI 3 , NaYbI 3 , LiYbI 3 , RbSmI 3 , CsSmI 3 , KSmI 3 , NaSmI 3 , or LiSmI 3 .