Full color organic electroluminescent device and method for fabricating the same
A full color organic electroluminescent device and a method for fabricating the same reduces misalignment errors caused by fine patterning of the emitting layer by reducing the steps of the fine patterning process. In particular, the blue emitting layer functions as a hole inhibition layer which results in superior color purity and improved stability for the color organic electroluminescent device. The use of such a blue emitting layer also reduces the manufacturing steps. The device comprises a substrate; a first electrode pattern formed on the substrate; a red emitting layer formed by patterning a red emitting material on a red pixel region of the first electrode pattern and a green emitting layer formed by patterning a green emitting material on a green pixel region of the first electrode pattern. A blue emitting layer is applied over the entire substrate, over the upper parts of the red and green emitting layers and a second electrode is formed on an upper part of the blue emitting layer.
1. A full color organic electroluminescent device comprising:
a substrate;
a first electrode pattern on the substrate and defining red, green and blue pixel regions;
a red emitting layer comprising red emitting phosphorescent material patterned on the red pixel region;
a green emitting layer comprising green emitting phosphorescent material patterned on the green pixel region;
a blue emitting layer comprising a blue fluorescence emitting material, wherein the blue emitting layer includes top and bottom surfaces, the bottom surface extending over the blue pixel region and over the red and green emitting layers; and
a second electrode over the blue emitting layer.
2. A full color organic electroluminescent device comprising:
a substrate;
a first electrode pattern on the substrate and defining red, green and blue pixel regions;
a red emitting layer comprising red phosphorescence emitting material doped with a material capable of emitting phosphorescence in the triplet state, wherein the red phosphorescence emitting material consists of a host that is a material capable of transferring energy to a phosphorescence dopant, wherein the host is selected from the group consisting of carbazole, arylamine, hydrazone, stylbene, star burst based derivatives and mixtures thereof, and the dopant is an organic complex of a metal selected from the group consisting of Ir, Pt, Eu and Tb;
a green emitting layer comprising a green phosphorescence emitting material doped with a material capable of emitting phosphorescence in the triplet state, wherein the green phosphorescence emitting material consists of a host that is CBP and a dopant that is an organic complex of a metal selected from the group consisting of Ir, Pt, Eu and Tb;
a blue emitting layer having top and bottom surfaces, the bottom surface extending over the blue pixel region and over the red and green emitting layers; and
a second electrode over the blue emitting layer.
3. The full color organic electroluminescent device according to claim 2 , wherein the concentration of the dopant for the red phosphorescence emitting material is from 7 to 15%, and the concentration of the dopant for the green phosphorescence emitting material is from 5 to 10%.
4. The full color organic electroluminescent device according to claim 1 , wherein the blue fluorescence emitting material is a material selected from the group consisting of:
a small molecular material selected from the group consisting of DPVBi, spiro-DPVBi, spiro-6P, distylbenzene (DSP) and distyrylarylene (DSA),
a small molecular material formed of two or more materials of host/dopant selected from the group consisting of DPVBi, spiro-DPVBi, spiro-6P, distylbenzene (DSP) and distyrylarylene (DSA), and
a polymeric material selected from PFO based polymer and PPV based polymer.
5. The full color organic electroluminescent device according to claim 1 , wherein thickness of the red and green phosphorescence emitting layers is from 100 to 1,000 Å.
6. The full color organic electroluminescent device according to claim 1 , wherein thickness of the blue emitting layer is 500 Å or less.
7. The full color organic electroluminescent device according to claim 1 , wherein the red and green phosphorescence emitting materials are formed by a method selected from the group consisting of vacuum deposition, wet type coating, ink jet printing and laser induced thermal imaging.
8. The full color organic electroluminescent device according to claim 1 , wherein the blue emitting material is formed by wet type coating or vacuum deposition.
9. A full color organic electroluminescent device comprising:
a substrate;
a first electrode pattern formed on the substrate, the electrode pattern defining red, green and blue pixel regions;
a red emitting layer comprising red phosphorescence emitting material patterned on the red pixel region
a green emitting layer comprising green phosphorescence emitting material patterned on the green pixel region;
a blue emitting layer formed over the blue pixel region and over the red and green phosphorescence emitting layers and comprising a blue fluorescence emitting material having a larger energy band gap than the red emitting material and the green emitting material; and
a second electrode formed over the blue emitting layer.
10. The full color organic electroluminescent device according to claim 9 , wherein the blue emitting material has a HOMO value of at least |5.5 eV |.
11. The full color organic electroluminescent device according to claim 9 , wherein the blue emitting material is a material selected from the group consisting of:
a small molecular fluorescence material selected from the group consisting of DPVBi, spiro-DPVBi, spiro-6P, distylbenzene (DSP) and distyrylarylene (DSA),
a small molecular material formed of two or more materials of host/dopant selected from the group consisting of DPVBi, spiro-DPVBi, spiro-6P, distylbenzene (DSP) and distyrylarylene (DSA), and
a polymeric fluorescence material selected from PFO based polymer and PPV based polymer.