MIXED LAYER, METHOD OF PREPARING THE MIXED LAYER, LIGHT-EMITTING DEVICE, AND ELECTRONIC APPARATUS

1 . A mixed layer, comprising:

a matrix material; and

a dopant composition,

wherein the dopant composition is doped in the matrix material,

wherein the dopant composition comprises a first dopant and a second dopant,

an amount by weight of the matrix material in the mixed layer is greater than an amount by weight of the dopant composition in the mixed layer,

the matrix material, the first dopant, and the second dopant are different from each other,

the matrix material does not comprise a transition metal,

the first dopant comprises a transition metal,

the mixed layer is a layer formed by deposition of the matrix material, the first dopant, and the second dopant,

the mixed layer has a concentration profile of the dopant composition with respect to a thickness of the mixed layer,

provided that T m1 >T p >T m1+2 is satisfied,

wherein,

T m1 is a melting point of the first dopant,

T p is a deposition temperature used in forming the mixed layer, and

T m1+2 is

a melting point of a pre-mixed composition of the first dopant and the second dopant, wherein the pre-mixed composition is crystalline; and

a fusion temperature of the pre-mixed composition of the first dopant and the second dopant, wherein the pre-mixed composition is amorphous,

wherein the pre-mixed composition comprises the first dopant and the second dopant, and is not doped in the matrix material.

2 . The mixed layer of claim 1 , wherein the matrix material comprises a hole-transporting compound, an electron-transporting compound, a bipolar compound, or a combination thereof.

3 . The mixed layer of claim 1 , wherein the first dopant comprises iridium or platinum.

4 . The mixed layer of claim 1 , wherein the mixed layer is a layer formed by deposition of a vapor-state matrix material and a vapor-state dopant composition, and

the vapor-state dopant composition comprises a vapor-state first dopant and a vapor-state second dopant.

5 . The mixed layer of claim 1 , wherein the second dopant comprises a transition metal.

6 . The mixed layer of claim 1 , wherein the second dopant comprises iridium or platinum.

7 . The mixed layer of claim 5 , wherein T m2 >T p is satisfied,

T p is as described in claim 1 , and

T m2 is a melting point of the second dopant.

8 . The mixed layer of claim 1 , wherein the second dopant does not comprise a transition metal.

9 . The mixed layer of claim 1 , wherein the second dopant comprises a cyclic group including a boron atom and a nitrogen atom as ring forming atoms.

10 . The mixed layer of claim 1 , wherein the mixed layer is an emission layer, and

each of the first dopant and the second dopant is an emitter;

the first dopant is an emitter, and the second dopant is a sensitizer; or

the first dopant is a sensitizer, and the second dopant is an emitter.

11 . The mixed layer of claim 1 , wherein the mixed layer is an emission layer, and

each of the first dopant and the second dopant emits red light;

each of the first dopant and the second dopant emits green light; or

each of the first dopant and the second dopant emits blue light.

12 . A method of preparing the mixed layer of claim 1 , the method comprising:

preparing:

a substrate,

a first deposition source comprising the first dopant and the second dopant,

a second deposition source comprising the matrix material, and

a vapor-state dopant composition provision unit configured to provide a vapor-state dopant composition from the first deposition source, wherein the vapor-state dopant composition comprises a vapor-state first dopant and a vapor-state second dopant;

preparing a deposition source moving unit on which the first deposition source and the second deposition source are arranged with a distance therebetween such that a region wherein the vapor-state dopant composition is present overlaps a region wherein a vapor-state matrix material is present, the vapor-state matrix material being released from the second deposition source;

arranging the deposition source moving unit at a first end below a surface of the substrate such that the substrate faces the deposition source moving unit; and

depositing the matrix material, the first dopant, and the second dopant on the surface of the substrate by

performing a one-way process of moving the deposition source moving unit in a direction away from the first end below the surface of the substrate toward a second end, or

performing, one or more times, a reciprocating process of moving the deposition source moving unit in a direction away from the first end below the surface of the substrate and toward a second end, and then immediately moving the deposition source moving unit in a direction away from the second end and toward the first end,

wherein the first deposition source comprises a first region and a second region, wherein the first region comprises the first dopant and does not comprise the second dopant, and wherein the second region comprises the second dopant and does not comprise the first dopant, wherein the first dopant and the second dopant in the first deposition source are not mixed with each other.

13 . The method of claim 12 , wherein the first deposition source further comprises a separation unit configured to separate the first region and the second region.

14 . The method of claim 12 , wherein the vapor-state dopant composition provision unit comprises:

a first unit configured to form the vapor-state dopant composition; and

a second unit configured to discharge the vapor-state dopant composition from the first unit.

15 . The method of claim 12 , wherein a deposition temperature of the depositing is less than a melting point of the first dopant, and

when a pre-mixed composition of the first dopant and the second dopant is crystalline, the deposition temperature of the depositing is greater than a melting point of the pre-mixed composition, and

when the pre-mixed composition of the first dopant and the second dopant is amorphous, the deposition temperature of the depositing is greater than a fusion temperature of the pre-mixed composition.

16 . A light-emitting device, comprising:

a first electrode;

a second electrode facing the first electrode; and

an interlayer arranged between the first electrode and the second electrode,

wherein the interlayer comprises the mixed layer of claim 1 .

17 . The light-emitting device of claim 16 , wherein the mixed layer is an emission layer.

18 . The light-emitting device of claim 16 , wherein the interlayer comprises:

m light-emitting units that comprise at least one emission layer; and

m−1 charge generation layers arranged between two neighboring light-emitting units of the m light-emitting units,

wherein m is an integer of 2 or greater, and

at least one light-emitting unit of the m light-emitting units comprises the mixed layer of claim 1 .

19 . The light-emitting device of claim 18 , wherein the at least one light-emitting unit of the m light-emitting units emits green light, and

at least one light-emitting unit of the remaining light-emitting units emits blue light.

20 . An electronic apparatus, comprising the light-emitting device of claim 16 .