Substrate for an organic light-emitting device and method for manufacturing the same
Provided is a substrate for an organic light emitting diode including a base substrate, a high refractive scattering layer formed on the base substrate, and having a scattering particle scattering light in a high refractive material, and an adhesive layer formed between the base substrate and the high refractive scattering layer to laminate the base substrate with the high refractive scattering layer, wherein the high refractive scattering layer has a structure in which the scattering particle is immersed in the high refractive material, an average thickness of the high refractive scattering layer is smaller than an average diameter of the scattering particle, a surface of the high refractive scattering layer laminated with the base substrate by the adhesive layer has unevenness formed by the scattering particle, the opposite surface of the high refractive scattering layer laminated with the base substrate by the adhesive layer has a planarized surface, and a method for manufacturing the same. The substrate may have an excellent degree of planarization and improved light extraction efficiency without degradation in performance of the diode, and low process and material costs and mass-production of the substrate may be easily achieved.
1. A method for manufacturing a substrate for an organic light emitting diode, comprising:
forming a scattering layer on a sacrificial substrate using a coating solution including a scattering particle and a high refractive material which comprises an organic or inorganic binder and a high refractive nano particle having an average diameter of 1 to 100 nm;
laminating a base substrate on the formed scattering layer by an adhesive layer; and
removing the sacrificial substrate,
wherein the scattering layer is formed to have an average thickness smaller than an average diameter of the scattering particle,
wherein the scattering particle is a bead formed of an organic material,
wherein the organic material includes an acryl-based resin, a styrene resin, an urethane resin, a melamine resin, a benzoguanamine resin, an epoxy resin, or a silicon resin,
wherein a surface of the scattering layer, from which the sacrificial substrate is removed, is a planarized surface that has a maximum height roughness of 0.001 to 0.3 μm in a 10×10 μm 2 region,
wherein the high refractive material has a refractive index of 1.7 or more with respect to a light having a wavelength of 400 nm, and
wherein a refractive index of the high refractive material (Na), a refractive index of the scattering particle (Nb), a refractive index of the base substrate (Nc), and a refractive index of the adhesive layer (Nd) satisfy any one of the relationships represented by Equations 1 and 2:
0.3≦ Na−Nb≦ 1.5, and [Equation 1]
0.01≦| Nc−Nd|≦ 0.2. [Equation 2]
2. The method of claim 1 , wherein the forming of the scattering layer includes:
after application of the coating solution to the sacrificial substrate, drying the applied coating solution; and
curing the dried coating solution.
3. The method of claim 1 , further comprising:
after the removing of the sacrificial substrate,
forming a coating layer on a surface of the scattering layer from which the sacrificial substrate is removed using a coating solution not including a scattering particle.
4. The method of claim 1 , wherein the high refractive nano particle is at least one selected from the group consisting of titanium dioxide, alumina, titanium oxide, zirconium oxide, cerium oxide, hafnium oxide, niobium pentoxide, tantalum pentoxide, indium oxide, tin oxide, indium tin oxide, zinc oxide, silicon, zinc sulfide, calcium carbonate, barium sulfate and magnesium oxide.
5. The method of claim 1 , wherein the scattering particle in the scattering layer is formed in a monolayer.
6. The method of claim 1 , wherein the scattering particle has an average diameter of 0.1 to 20 μm.
7. The method of claim 1 , wherein the scattering particle is in a spherical shape.
8. The method of claim 1 , wherein forming the scattering layer on the sacrificial substrate using the coating solution comprises applying the coating solution including both the scattering particle and the binder to the sacrificial substrate; drying the applied coating solution; and curing the dried coating solution.
9. The method claim 8 , wherein the curing is a UV curing method.
10. The method of claim 8 , wherein the adhesive layer is formed by applying an adhesive material to the scattering layer.
11. The method of claim 10 , further comprising:
after the removing of the sacrificial substrate,
forming a coating layer on a surface of the scattering layer from which the sacrificial substrate is removed using a coating solution not including a scattering particle.
12. The method of claim 1 , wherein the adhesive layer is formed by applying an adhesive material to the scattering layer.
13. The method of claim 1 , wherein the binder is a fluorine-based polymer or a styrene-based polymer.