Long operating life for polymer light-emitting diodes
AssigneeUniax Corporation
InventorsChi Zhang, Gang Yu, Yong Cao
Life of this patent
Estimating the term…
Abstract
Long-lived organic light-emitting diodes are achieved by positioning a layer comprising polyaniline in the emeraldine salt form directly contiguous with the anode side of the active light-emitting layer. Particular advantages are achieved if the emeraldine salt-containing layer has a sheet resistance of at least about 10.sup.3 ohms per square which can be achieved by casting the layer from solution in a polar solvent, most particularly, DMSO. The LED's can find advantageous application in displays where they exhibit long life and marked resistance to blurring, spreading or other degradations over time.
Claims15
An organic light-emitting diode having an operating lifetime in excess of 1000 hours comprising
- a semitransparent anode having a sheet resistance of less than 10.sup.3 ohms per square separated from
- an organic light-emitting layer by
- an intermediate layer comprising polyaniline emeraldine salt said intermediate layer having a sheet resistance of more than 10.sup.3 ohms per square.
An organic light-emitting diode having an operating lifetime in excess of 1000 hours comprising in layer order
- a semitransparent anode layer having a sheet resistance of less than 10.sup.3 ohms per square
- an intermediate layer comprising polyaniline emeraldine salt said intermediate layer having a sheet resistance of more than 10.sup.3 ohms per square
- an organic light-emitting layer and
- a cathode layer.
A method for forming an organic light-emitting diode having an operating lifetime in excess of 1000 hours, said diode having in layer order
- a semitransparent anode layer having a sheet resistance of less than 10.sup.3 ohms per square
- an intermediate layer comprising polyaniline emeraldine salt said intermediate layer having a sheet resistance of more than 10.sup.3 ohms per square
- an organic light-emitting layer and
- a cathode layer, comprising
- depositing the intermediate layer upon the anode layer from solution comprising emeraldine salt in a liquid selected from the group consisting of DMSO, tetramethylsulfoxide, 4-butylactone, propylene carbonate, chloroform, chlorobenzene, dichloromethane, benzyl alcohol, trifluoroethanol, octafluoropentanol, formic acid, acetic acid, trichloroacetic acid and mixtures thereof,
- depositing the organic light-emitting layer upon the intermediate layer and depositing the cathode layer upon the light emitting layer.
Dependencies are inferred from the claim text.