Hybrid polymer light-emitting devices

• US 20080084158A1
• Filed: 01/18/2007
• Published: 04/10/2008
• Est. Priority Date: 10/05/2006
• Status: Active Grant

• Current Assignee: Alan J. Heeger, Guillermo C. Bazan, Yan Shao
• Original Assignee: Alan J. Heeger, Guillermo C. Bazan, Yan Shao
• Inventors: Bazan, Guillermo C., Shao, Yan, Heeger, Alan J.
• Granted Patent: US 7,745,520 B2
• Time in Patent Office: Days
• US Class Current: 313/503
• CPC Class Codes: C08K 5/19 Quaternary ammonium compounds
• CPC Class Codes: C08K 5/42 Sulfonic acids; Derivatives thereof
• CPC Class Codes: H10K 50/135 comprising mobile ions
• CPC Class Codes: H10K 85/114 Poly-phenylenevinylene; Derivatives thereof

Abstract

Mixtures and light-emitting devices that incorporate such mixtures are disclosed in which a soluble phenyl-substituted poly(para-phenylene vinylene) (PPV) copolymer (“superyellow”) is used as the host light-emitting polymer and methyltrioctylammonium trifluoromethanesulfonate, an ionic liquid, is used to introduce a dilute concentration of mobile ions into the emitting polymer layer. These mixtures and devices incorporating them are able to combine some of the characteristics of polymer light emitting diodes (PLEDs) and polymer light-emitting electrochemical cells (PLECs).

Claims

1. A soluble mixture comprising a single phase combination of a light-emitting polymer and a soluble ionic liquid.

2. The mixture of claim 1, wherein said light-emitting polymer is a compound selected from the group consisting of phenyl-substituted poly(para-phenylene vinylene) (PPV), poly(2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylene-vinylene) (MEH-PPV), polyfluorenylene (PF), poly(1,4-phenylene) (PP), and derivatives thereof.

3. The mixture of claim 2, wherein the compound is phenyl-substituted poly(para-phenylene vinylene) (PPV) copolymer.

4. The mixture of claim 1, wherein said ionic liquid is a compound selected from the group consisting of methyltrioctylammonium trifluoromethanesulfonate, 1-Methyl-3-octylimidazolium octylsulfate, 1-Butyl-2,3-dimethylimidazolium octylsulfate, 1-octadecyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, 1-octadecyl-3-methylimidazolium tris(pentafluoroethyl)trifluorophosphate, 1,1-dipropylpyrrolidinium bis(trifluoromethylsulfonyl)imide, trihexyl(tetradecyl)phosphonium bis(1,2-benzenediolato(2-)—

O,O′

)borate, and N,N,N′

,N′

,N″

-pentamethyl-N″

propylguanidinium trifluoromethanesulfonate.

5. The mixture of claim 4, wherein the ionic liquid is methyltrioctylammonium trifluoromethanesulfonate.

6. The mixture of claim 1, wherein the ionic liquid has a melting temperature range of about 50°

C. to 200°

C.

7. The mixture of claim 6, wherein the ionic liquid has a melting temperature of about 56°

C.

8. The mixture of claim 1, wherein the light-emitting polymer is used with about a 2% solution of the ionic liquid.

9. The mixture of claim 1, wherein the light-emitting polymer is a phenyl-substituted poly(para-phenylene vinylene) (PPV) copolymer and the ionic liquid is methyltrioctylammonium trifluoromethanesulfonate.

10. The mixture of claim 1, further comprising a compound with a T_g range from 80°

C. to 300°

C.

11. The mixture of claim 10, wherein the compound is selected from a group consisting of high molecular weight polystyrene, Poly[[octahydro-5-(methoxycarbonyl)-5-methyl-4,7-methano-1H-indene-1,3-diyl]-1,2-ethanediyl], and polymethyl methacrylate (PMMA).

12. The mixture of claim 10, wherein the compound is selected from a group consisting of phenylvinylene dendrimer, alkylphenyl dendrimer, phenylphenyl dendrimer, phenylene dendrimer, carbazole dendrimer, and phenylazomethine dendrimer.

13. The mixture of claim 10, wherein the compound is selected from a group consisting of benzocyclobutene homopolymer, benzocyclobutene copolymer, pentadiene homopolymer and copolymer, and trifluorovinyl ether derivatives.

14. A light-emitting device comprising a pair of electrodes, and an emitting polymer active layer between the pair of electrodes, said emitting polymer layer comprising a single phase combination of a light-emitting polymer and an ionic liquid.

15. A light-emitting device comprising a pair of electrodes, and an emitting polymer active layer between the pair of electrodes, said emitting polymer layer comprising a single phase combination of a light-emitting polymer and an ionic liquid, said device formed by the process of:

i) precoating a glass substrate with indium-tin-oxide;

ii) spin-casting upon said indium-tin-oxide -coated glass substrate, a thin layer of soluble polymer;

iii) depositing onto the layer of soluble polymer, a layer of a solution comprising the host light-emitting polymer and the ionic liquid containing a concentration of mobile ions, and

iv) evaporating aluminum through a mask to form a cathode.

16. The light-emitting device of claim 15, wherein the light-emitting polymer is a phenyl-substituted poly(para-phenylene vinylene) (PPV) copolymer and the ionic liquid is methyltrioctylammonium trifluoromethanesulfonate.

17. The light-emitting device of claim 15, further comprising a compound with a T_g range from 80°

C. to 300°

C.

18. A method for generating a useful level of light comprising:

applying a voltage across the anode and cathode of a light emitting-device comprising a pair of electrodes, and an emitting polymer active layer between the pair of electrodes, said emitting polymer layer comprising a single phase combination of a light-emitting polymer and an ionic liquid, and

detecting the light emitted from said device.

19. A mixture comprising a combination of a light-emitting polymer and an ionic liquid, wherein said combination is co-soluble in a selected solvent and capable of forming a single phase material.

20. The mixture of claim 19, wherein the solvent is selected from a group consisting of toluene, hexane, acetonitrile, 1,1-dichloroethane, 1,2-dichloroethane, dichloromethane, benzene, dialkylbenzene, dialkoxylbenzene, chloroform, hexane, cyclohexane, and cyclohexanone.

21. The mixture of claim 19, wherein the solvent is toluene.