Using hole- or electron-blocking layers in color OLEDS

1. A method for forming an organic light-emitting device comprising:

a) depositing a first electrode over a substrate;

b) depositing a first emissive layer over the first electrode for producing a first colored light in response to hole-electron recombination;

c) selectively patternwise depositing a first electron-blocking layer over the first emissive layer;

d.1) depositing a second emissive layer over the first electron-blocking layer which in response to hole-electron recombination emits a second colored light different from the first colored light emitted from the first emissive layer;

d.2) selectively patternwise depositing a second electron-blocking layer over the second emissive layer;

d.3) depositing a third emissive layer over the second electron-blocking layer which in response to a hole-electron recombination emits a third color of light different from the first and second colored lights of first and second emissive layers;

e) depositing a second electrode over the third emissive layer; and

f) whereby the patternwise deposition of the electron-blocking layers has been selected to substantially shift hole-electron recombination from the first to the second emissive layers and from the second to the third emissive layer.

2. The method of claim 1 wherein either the first, second, or both the first and the second electrode(s) is patterned during deposition.

3. The method of claim 1 further including the step of depositing a hole-transporting layer between the first electrode and the first emissive layer.

4. The method of claim 1 further including the step of depositing an electron-transporting layer between the third emissive layer and the second electrode.

5. The method of claim 4 wherein the highest occupied molecular orbital and lowest unoccupied molecular orbital levels of each electron-blocking layer are such that the lowest unoccupied molecular orbital is at a higher energy than the lowest unoccupied molecular orbital of the electron-transporting layer while the highest occupied molecular orbital has an energy level near or above the highest occupied molecular orbital of the hole-transporting layer.

6. The method of claim 5 wherein the electron-blocking layer consists of an arylamine compound, a benzidine compound, or a carbazole compound.

7. The method of claim 1 wherein one or more of the electron-blocking layers are deposited patternwise by a laser thermal transfer process.

8. The method of claim 1 wherein one or more of the electron-blocking layers are deposited patternwise through a shadow mask.

9. The method of claim 1 wherein the two electron-blocking layers comprise the same material.