Fabrication of poly(p-phenyleneacetylene) light-emitting diodes
AssigneeIowa State University Research Foundation, Inc.
InventorsJoseph Shinar, Leland S. Swanson, Feng Lu, Yiwei Ding
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Abstract
Acetylene containing poly(p-phenyleneacetylene) (PPA) - based light-emitting diodes (LEDs) are provided. The LEDs are fabricated by coating a hole-injecting electrode, preferably an indium tin oxide (ITO) coated glass substrate, with a PPA polymer, such as a 2,5-dibutoxy or a 2,5-dihexoxy derivative of PPA, dissolved in an organic solvent. This is then followed by evaporating a layer of material capable of injecting electrons, such as A1 or A1/Ca, onto the polymer to form a base electrode. This composition is then annealed to form efficient EL diodes.
Claims20
A method for producing a polymer-based light-emitting diode comprising the steps of:
- (a) providing a hole-injecting electrode;
- (b) coating the hole-injecting electrode with a layer of a conjugated polymer to form a conjugated polymer-coated hole-injecting electrode;
- (c) coating the conjugated polymer-coated hole-injecting electrode with a layer of an electron-injecting material to form an electron-injecting electrode;
- wherein the hole-injecting electrode, polymer layer, and electron-injecting electrode form a polymer-based light-emitting diode (LED);
- and
- (d) annealing the polymer-based LED at a temperature and for a period of time effective to reduce the electroluminescence threshold voltage by at least about 20%.
A method for producing a polymer-based light-emitting diode comprising the steps of:
- (a) providing a hole-injecting electrode;
- (b) coating the hole-injecting electrode with a conjugated polymer to form a conjugated polymer-coated hole-injecting electrode, wherein the conjugated polymer is a soluble poly(p-phenyleneacetylene) polymer of the formula --[--C.tbd.C--Ar--C.tbd.C--Ar--].sub.n --, having a number average molecular weight of at least about 2,000, wherein Ar is an arylene group and n.gtoreq.5;
- (c) coating the conjugated polymer-coated hole-injecting electrode with a layer of an electron-injecting material to form an electron-injecting electrode;
- wherein the hole-injecting electrode, polymer layer, and electron-injecting electrode form a polymer-based light-emitting diode (LED);
- and
- (d) annealing the polymer-based LED at a temperature and for a period of time effective to reduce the catastrophic failure rate by at least about 2%.
A method for producing a polymer-based light-emitting-diode comprising the steps of:
- (a) providing an indium-tin-oxide-coated (ITO) glass substrate having a first and second surface, wherein the first surface has the ITO coated thereon;
- (b) removing an amount of the ITO from the first surface to expose a portion of the glass substrate;
- (c) filtering an organic solvent solution of a poly(p-phenyleneacetylene) polymer of the formula --[--C.tbd.C--Ar--C.tbd.C--Ar--].sub.n --, having a number average molecular weight of at least about 2,000, wherein Ar is an arylene group and n.gtoreq.5;
- (d) spin-coating the solution of a poly(p-phenyleneacetylene) polymer onto the ITO glass substrate first surface having a portion of the glass substrate exposed by wetting the ITO glass substrate with the polymer solution while spinning the ITO glass substrate to form a polymer-coated ITO glass substrate;
- (e) evaporating a layer of aluminum onto the polymer-coated ITO glass substrate to form an electron-injecting electrode;
- wherein the hole-injecting electrode, polymer layer, and electron-injecting electrode form a polymer-based light-emitting diode (LED);
- and
- (f) annealing the LED.
Dependencies are inferred from the claim text.