White phosphorescent organic light emitting devices
A device is provided. The device includes an anode, a cathode and a double emissive layer disposed between the anode and the cathode. The double emissive layer includes a first organic emissive layer and a second organic emissive layer. The second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer. The device also includes a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode. The device also includes a hole transport layer disposed between the blocking layer and the anode. At least one of the anode and the cathode is transmissive.
1. A device, comprising:
an anode;
a cathode;
a first organic emissive layer, further comprising:
first phosphorescent material having a concentration of 15-35 wt % in the first organic emissive layer, wherein the first phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 400 nm and 500 nm; and
a first host material having a triplet energy at least 0.2 eV and not more than 1.0 eV greater than the triplet energy of the first phosphorescent material;
wherein the first organic emissive layer is disposed between the anode and the cathode;
a second organic emissive layer further comprising:
a second phosphorescent material having a concentration of 15-35 wt % in the second organic emissive layer, wherein the second phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 500 nm and 600 nm;
a third phosphorescent material having a concentration of 0.1-3 wt % in the second organic emissive layer, wherein the third phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 600 nm and 700 nm;
a second host material having a triplet energy greater than that of the third phosphorescent emissive material;
wherein the second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer;
a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode, the blocking layer having a lowest unoccupied molecular orbital that is at least 0.1 eV greater than the lowest unoccupied molecular orbital of the second host material;
a hole transport layer disposed between the blocking layer and the anode;
wherein at least one of the anode and the cathode is transmissive.
2. The device of claim 1 , wherein the anode is transmissive and the cathode is reflective.
3. The device of claim 2 , wherein the second organic emissive layer is disposed closer to the anode than the first organic emissive layer.
4. The device of claim 1 , wherein the anode is reflective and the cathode is transmissive.
5. The device of claim 4 , wherein the second organic emissive layer is disposed closer to the cathode than the first organic emissive layer.
6. The device of claim 1 , wherein the first host material has a triplet energy at least 0.2 eV and not more than 0.5 eV greater than the triplet energy of the first phosphorescent material.
7. The device of claim 1 , wherein the hole transport layer consists essentially of NPD.
8. The device of claim 1 wherein the hole transport layer has a hole mobility of at least 5×10 −4 cm 2 V −1 s −1 .
9. The device of claim 1 , wherein the anode consists essentially of indium zinc oxide.
10. The device of claim 1 , wherein the voltage drop across the device at a luminance of 1000 cd/m 2 is 3.5 eV-4.1 eV.
11. The device of claim 1 , wherein the voltage drop across the device at a luminance of 1000 cd/m 2 is less than 3.7 eV.
12. The device of claim 1 , wherein the second phosphorescent material is compound B.
13. The device of claim 1 , wherein the first organic emissive layer has a thickness of 4 nm to 10 nm.
14. The device of claim 1 , wherein the blocking layer has a thickness of 12-37 nm and the hole transport layer has a thickness of 12-37 nm.
15. A consumer product, comprising a device, the device further comprising:
an anode;
a cathode;
a first organic emissive layer, further comprising:
first phosphorescent material having a concentration of 15-35 wt % in the first organic emissive layer, wherein the first phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 400 nm and 500 nm; and
a first host material having a triplet energy at least 0.2 eV and not more than 1.0 eV greater than the triplet energy of the first phosphorescent material;
wherein the first organic emissive layer is disposed between the anode and the cathode;
a second organic emissive layer further comprising:
a second phosphorescent material having a concentration of 15-35 wt % in the second organic emissive layer, wherein the second phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 500 nm and 600 nm;
a third phosphorescent material having a concentration of 0.1-3 wt % in the second organic emissive layer, wherein the third phosphorescent material has a peak emissive wavelength in the visible spectrum at a wavelength between 600 nm and 700 nm;
a second host material having a triplet energy greater than that of the third phosphorescent emissive material;
wherein the second organic emissive layer is disposed between the anode and the cathode, and is adjacent to the first organic emissive layer;
a blocking layer disposed adjacent to the second organic emissive layer and between the second organic emissive layer and the anode, the blocking layer having a lowest unoccupied molecular orbital that is at least 0.1 eV greater than the lowest unoccupied molecular orbital of the second host material;
a hole transport layer disposed between the blocking layer and the anode;
wherein at least one of the anode and the cathode is transmissive.