Color-change material layer

1. An OLED device including,

a substrate;

a first electrode;

a transparent second electrode;

an organic light emitting layer disposed between the first electrode and the transparent second electrode; and

wherein the transparent second electrode comprises:

color-change particles that convert light of a second frequency range higher than a first frequency range to light of the first frequency range;

a conductive transparent material having a refractive index of at least 1.6 intermixed with the color-change particles,

wherein the color-change particles are formed at a higher concentration on the side of the transparent second electrode away from the organic light emitting layer and at a lower concentration at the side of the transparent second electrode closest to the organic light emitting layer, and

wherein the transparent second electrode is substantially non-scattering to light of the first frequency range.

2. The OLED device of claim 1 wherein the transparent second electrode is substantially non-scattering to light of the second frequency range.

3. The OLED device of claim 1 wherein the transparent second electrode is substantially non-scattering to white light.

4. The OLED device of claim 1 wherein the color-change particles within the transparent second electrode are substantially non-scattering to light of the first frequency range, second frequency range, and/or white light.

5. A method of forming the transparent second electrode according to claim 1 comprising the steps of:

providing a color-change material that converts light of a second frequency range higher than a first frequency range to light of the first frequency range;

providing transparent particles having a refractive index of at least 1.6 and a diameter of less than 400 nm; and

mixing the color-change material and transparent particles in a binder, and coating the mixture on a substrate to form the transparent second electrode having a refractive index of at least 1.6, wherein the layer is substantially non-scattering to light of the first frequency range.

6. A method of forming the transparent second electrode according to claim 1 comprising the steps of:

providing color-change material particles that converts light of a second frequency range higher than a first frequency range to light of the first frequency range in a binder to form a dispersion; and

coating the dispersion on a substrate and drying the dispersion to form a non-planar surface of color-change material particles;

depositing a transparent material having an optical index of 1.6 on the dried dispersion, thereby intermixing the deposited transparent material with the color-change material and forming the transparent second electrode having a refractive index of at least 1.6, wherein the layer is substantially non-scattering to light of the first frequency range.

7. The OLED device of claim 1 wherein the conductive transparent material having a refractive index of at least 1.6 is ITO.

8. An OLED device comprising:

a substrate;

one or more color filters formed above the substrate and transmitting light having a first frequency range;

a first transparent electrode formed over the color filters comprising color-change particles that convert light of a second frequency range higher than the first frequency range to light of the first frequency range, and a conductive transparent material having a refractive index of at least 1.6 intermixed with the color-change particles, wherein the first transparent electrode is substantially non-scattering to light of the first frequency range and the color-change particles are formed at a higher concentration on one side of the first transparent electrode and at a lower concentration at the other side of the first transparent electrode;

one or more layers of organic light-emitting materials which emits light in at least the second frequency range in response to a current passed there-through formed over the first transparent electrode; and

a second electrode formed over the one or more layers of light-emitting materials; and

wherein the OLED device comprises a plurality of differently colored light-emitting elements formed over different locations on the substrate, each differently colored light-emitting element comprises a differently colored color filter and corresponding color-change particles and wherein the different colors include at least two of red, green or blue.

9. The OLED device of claim 8 wherein the one or more layers of light emitting materials emit broadband or white light.

10. The OLED device of claim 8 further comprising light-emitting elements formed in different locations that do not include color-change particles.

11. The OLED device of claim 8 wherein the OLED device forms a full-color display having red, green, blue, and white light-emitting elements.

12. The OLED device of claim 8 wherein the first transparent electrode is formed directly on the one or more color filters.

13. The OLED device of claim 8 wherein the conductive transparent material having a refractive index of at least 1.6 is ITO.