High refractive index nanocomposite layer
The present invention relates to an OLED internal light extraction scheme with graded-index layer and embedded scattering particles.
1. An organic light emitting diode (OLED) lighting device comprising an internal light extraction layer, wherein the internal light extraction layer comprises:
a high refractive index nanocomposite comprising inorganic nanocrystals embedded in a polymer matrix, wherein
the nanocomposite has a refractive index of 1.7 and higher at 400 nm in at least part of the nanocomposite, and wherein
a 3-4 micron thick sample of the nanocomposite has an optical transmittance of at least 90% over a range of 440 nm to 800 nm.
2. The OLED lighting device of claim 1 , wherein the nanocrystals comprise ZrO 2 nanocrystals.
3. The OLED lighting device of claim 1 , wherein the nanocrystals have a size smaller than 10 nm in at least one dimension.
4. The OLED lighting device of claim 1 , wherein the polymer matrix comprises an acrylic polymer.
5. The OLED lighting device of claim 1 , wherein the internal light extraction layer has an index gradient.
6. The OLED lighting device of claim 5 , wherein the index gradient results at least in part from a concentration gradient of the inorganic nanocrystals.
7. The OLED lighting device of claim 1 , wherein the internal light extraction layer further includes light scattering particles.
8. The OLED lighting device of claim 7 , wherein the scattering particles comprise TiO 2 particles.
9. The OLED lighting device of claim 7 , wherein the scattering particles comprises polymer beads.
10. The OLED lighting device of claim 7 , wherein the scattering particles comprise agglomerated ZrO 2 nanocrystals.
11. The OLED lighting device of claim 1 , wherein the inorganic nanocrystals are capped nanocrystals.
12. The OLED lighting device of claim 2 , wherein the inorganic nanocrystals are capped nanocrystals.
13. An organic light emitting diode (OLED) lighting device comprising an internal light extraction layer comprising:
a high refractive index nanocomposite comprising inorganic nanocrystals embedded in a polymer matrix in an amount of greater than 70% by weight of the nanocomposite, wherein
the nanocomposite has a refractive index of 1.7 and higher at 400 nm in at least part of the nanocomposite, and wherein
a 3-4 micron thick sample of the nanocomposite has an optical transmittance of at least 90% over the range of 440 nm to 800 nm.
14. The OLED lighting device of claim 13 , wherein the nanocrystals comprise ZrO 2 nanocrystals.
15. The OLED lighting device of claim 13 , wherein the inorganic nanocrystals are capped nanocrystals.
16. The OLED lighting device of claim 14 , wherein the inorganic nanocrystals are capped nanocrystals.
17. The OLED lighting device of claim 1 , wherein at least a part of the nanocomposite has a refractive index of 1.8 and higher at 400 nm.
18. The OLED lighting device of claim 13 , wherein at least a part of the nanocomposite has a refractive index of 1.8 and higher at 400 nm.
19. The OLED lighting device of claim 1 , wherein at least a part of the nanocomposite has a refractive index of 1.9 at 400 nm.
20. The OLED lighting device of claim 13 , wherein at least a part of the nanocomposite has a refractive index of 1.9 at 400 nm.