Light-emitting devices and methods for making and using the same

1. A light-emitting device comprising:

a transparent substrate;

a light-extracting polymer layer having one or more elevated regions and one or more lowered regions distributed on a surface of the light-extracting polymer layer facing away from the transparent substrate, wherein the one or more elevated regions comprise a first material and the one or more lowered regions comprise a second material;

a first electrode layer, wherein the light-extracting polymer layer is disposed between the first electrode layer and the transparent substrate;

a second electrode layer; and

a light-emitting layer disposed between the first electrode layer and the second electrode layer, wherein the light-emitting layer is configured to emit light when a voltage is applied between the first electrode layer and the second electrode layer.

2. The light-emitting device of claim 1 , wherein:

the first material of the one or more elevated regions of the light-extracting polymer layer comprises a first thermoplastic polymer; and

the second material of the one or more lowered regions of the light-extracting polymer layer comprises a second thermoplastic polymer.

3. The light-emitting device of claim 2 , wherein each of the first thermoplastic polymer and the second thermoplastic polymer is a polycarbonate, an acrylic, a polyolefin, a polyester, a polystyrene, or a copolymer thereof.

4. The light-emitting device of claim 2 , wherein:

the first thermoplastic polymer comprises a monomer unit represented by Formula I:

and

the second thermoplastic polymer comprises a monomer unit represented by Formula II:

5. The light-emitting device of claim 2 , wherein:

the first thermoplastic polymer is polymethyl methacrylate, or a copolymer thereof;

the second thermoplastic polymer is polystyrene, or a copolymer thereof; and

a ratio by weight of the first thermoplastic polymer to the second thermoplastic polymer is about 1:10 to about 10:1.

6. The light-emitting device of claim 1 , wherein:

the light-extracting polymer layer has an average thickness of less than about 250 nm;

the one or more elevated regions are periodic structures, quasi-periodic structures or random structures;

the one or more elevated regions are corrugated structures, worm-like structures or a combination thereof;

the one or more elevated regions are nano-sized, micro-sized or a combination thereof;

an average spacing between adjacent elevated regions in the light-extracting polymer layer is less than about 1 μm;

the light-extracting polymer layer has at least 10 8 elevated regions per square centimeter (cm 2 );

each of the one or more elevated regions in the light-extracting polymer layer has a height of at least 15 nm;

the transparent substrate comprises ceramic or glass; and

each of the first electrode layer and the second electrode layer comprises silver, gold, indium tin oxide, or a combination thereof.

7. The light-emitting device of claim 1 , wherein the transparent substrate has a water contact angle of less than about 80°.

8. The light-emitting device of claim 1 , further comprising:

a hole-transport layer disposed between the first electrode layer and the light-emitting layer; or

a hole-injection layer disposed between the first electrode layer and the light-emitting layer.

9. The light-emitting device of claim 8 , wherein:

the hole-transport layer comprises N,N′-diphenyl-N,N′-bis(1-naphthyl)-(1,1′-biphenyl)-4,4′-diamine; or

the hole-injection layer comprises molybdenum trioxide.

10. The light-emitting device of claim 1 , further comprising:

an electron-injection layer disposed between the second electrode layer and the light-emitting layer; or

an electron-transport layer disposed between the second electrode layer and the light-emitting layer.

11. The light-emitting device of claim 1 , wherein the light-emitting layer comprises a phosphorescent material or a fluorescent material.

12. The light-emitting device of claim 1 , wherein the light-emitting device has a maximum luminance of at least about 20,000 cd/m 2 .

13. The light-emitting device of claim 1 , wherein at least one of the first electrode layer, the light-emitting layer, or the second electrode layer has one or more elevated regions on a corresponding surface of the first electrode layer, the light-emitting layer, or the second electrode layer that faces away from the transparent substrate.

14. The light-emitting device of claim 1 , wherein:

the first material of the one or more elevated regions comprises a first solute included in a solution from which the light-extracting polymer layer is formed; and

the second material of the one or more lowered regions comprises a second solute included in the solution from which the light-extracting polymer layer is formed.