Advanced light extraction structure
Preparation of semiconductor nanocrystals and their dispersions in solvents and other media is described. The nanocrystals described herein have small (1-10 nm) particle size with minimal aggregation and can be synthesized with high yield. The capping agents on thews-synthesized nanocrystals as well as nanocrystals which have undergone cap exchange reactions result in the formation of stable suspensions in polar and nonpolar solvents which may then result in the formation of high quality nanocomposite films.
1. An organic light emitting diode (OLED) display comprising,
in order:
a planarization layer,
an array of lenses, and
an array of light emitting pixels, wherein
the array of lenses comprise a nanocomposite having a refractive index in the range of greater than 1.7 to 1.9 at 400 nm, the nanocomposite comprising inorganic nanocrystals and a polymeric matrix, wherein the refractive index of the nanocrystals is greater than the refractive index of the polymeric matrix; and wherein
the planarization layer has a refractive index that is less than the refractive index of the nanocomposite; and wherein
at least one of the lenses is arranged so as to enhance overall light extraction efficiency from at least one pixel.
2. The OLED display of claim 1 , further comprising an encapsulation or a substrate layer in contact with the planarization layer on a surface of the planarization layer opposite a surface facing the array of light emitting pixels.
3. The OLED display of claim 1 , wherein the nanocomposite is UV curable.
4. The OLED display of claim 1 , wherein the nanocomposite is thermally curable.
5. The OLED display of claim 1 , wherein the nanocomposite comprises ZrO 2 , TiO 2 , ZnO, MgO, HfO 2 , Nb 2 O 5 , Ta 2 O 5 , or Y 2 O 3 nanocrystals.
6. The OLED display of claim 5 , wherein the nanocrystals have a size of less than 10 nm in at least one dimension.
7. The OLED display of claim 5 , wherein the nanocomposite comprises a polymer, and wherein the polymer optionally comprises an acrylic, an epoxy or a silicone.
8. The OLED display of claim 7 , wherein the polymer comprises a siloxane, a polycarbonate, a polyurethane, a polyimide, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(styrene sulfonate) (PSS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or poly(4,4-dioctylcyclopentadithiophene).
9. The OLED display of claim 1 , wherein at least one of the lenses covers a single pixel.
10. The OLED display of claim 1 , wherein at least one of the lenses covers multiple pixels.
11. The OLED display of claim 1 , wherein a lens of the array of lenses comprises a spherical surface, a semi-spherical surface, a hyper-hemispherical surface or a parabolic surface.
12. The OLED display of claim 1 , wherein a lens of the array of lenses comprises a concave surface, a convex surface, a sub-wavelength pyramid array surface or a textured surface.
13. The OLED display of claim 1 , wherein a lens of the array of lenses comprises a graded or gradient index profile along at least one dimension of the lens.
14. The OLED display of claim 1 , wherein the array of lenses is separated from the array of light emitting pixels by a distance of less than the wavelength of the highest energy photons emitted by the array of pixels.
15. The OLED display of claim 1 , wherein the nanocrystals are at least partially capped.
16. An organic light emitting diode (OLED) display comprising,
in order:
an array of lenses, and
an array of light emitting pixels, wherein
the array of lenses comprises a nanocomposite, wherein the nanocomposite comprises inorganic nanocrystals and a polymeric matrix, the nanocomposite having a refractive index between 1.6 and 1.9 at 400 nm, wherein the refractive index of the nanocrystals is greater than the refractive index of the polymeric matrix; and wherein
at least one of the lenses is arranged so as to enhance overall light extraction efficiency from at least one pixel, and wherein
the array of lenses is not in contact with a planarization layer or a substrate layer.
17. The OLED display of claim 16 , wherein the nanocomposite is UV curable.
18. The OLED display of claim 16 , wherein the nanocomposite is thermally curable.
19. The OLED display of claim 16 , wherein the nanocomposite comprises ZrO 2 , TiO 2 , ZnO, MgO, HfO 2 , Nb 2 O 5 , Ta 2 O 5 , or Y 2 O 3 nanocrystals.
20. The OLED display of claim 19 , wherein the nanocrystals have a size of less than 10 nm in at least one dimension.
21. The OLED display of claim 16 , wherein the nanocomposite comprises a polymer, and wherein the polymer optionally comprises an acrylic, an epoxy or a silicone.
22. The OLED display of claim 21 , wherein the polymer comprises a siloxane, a polycarbonate, a polyurethane, a polyimide, poly(3,4-ethylenedioxythiophene) (PEDOT), poly(styrene sulfonate) (PSS), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or poly(4,4-dioctylcyclopentadithiophene).
23. The OLED display of claim 16 , wherein at least one of the lenses covers a single pixel.
24. The OLED display of claim 16 , wherein at least one of the lenses covers multiple pixels.
25. The OLED display of claim 16 , wherein a lens of the array of lenses comprises a spherical surface, a semi-spherical surface, a hyper-hemispherical surface, or a parabolic surface.
26. The OLED display of claim 16 , wherein a lens of the array of lenses comprises a concave surface, a convex surface, a sub-wavelength pyramid array surface, or a textured surface.
27. The OLED display of claim 16 , wherein a lens of the array of lenses comprises a graded or gradient index profile along at least one dimension of the lens.
28. The OLED display of claim 16 , wherein the array of lenses is separated from the array of light emitting pixels by a distance of less than the wavelength of the highest energy photons emitted by the array of pixels.
29. The OLED display of claim 16 , wherein the nanocrystals are at least partially capped.