Process for forming an electroactive layer

• US 9,209,398 B2
• Filed: 03/09/2010
• Issued: 12/08/2015
• Est. Priority Date: 03/09/2009
• Status: Active Grant

• Current Assignee: LG Chem Limited (LG Corporation)
• Original Assignee: E I Du Pont de Nemours and Company Dupont Displays Incorporated
• Inventors: Chesterfield, Reid John, Butler, Justin, Sant, Paul Anthony
• Primary Examiner(s): Murata, Austin
• Application Number:
  US13/203,279
• Publication Number:
  US 20110305824A1
• Time in Patent Office: 2,100 Days
• Field of Search: 427/64
• US Class Current: 1/1
• CPC Class Codes: F26B 21/14 using gases or vapours other than air or steam , e.g. inert gases
• CPC Class Codes: F26B 5/04 by evaporation or sublimation of moisture under reduced pressure, e.g. in a vacuum F26B11/049 and F26B17/128 take precedence
• CPC Class Codes: H10K 50/11 characterised by the electroluminescent [EL] layers
• CPC Class Codes: H10K 59/122 Pixel-defining structures or layers, e.g. banks
• CPC Class Codes: H10K 59/35 comprising red-green-blue [RGB] subpixels
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass
• CPC Class Codes: H10K 71/12 using liquid deposition, e.g. spin coating
• CPC Class Codes: H10K 71/40 Thermal treatment, e.g. annealing in the presence of a solvent vapour
• CPC Class Codes: H10K 71/811 Controlling the atmosphere during processing H10K71/40 takes precedence
• CPC Class Codes: H10K 85/615 Polycyclic condensed aromatic hydrocarbons, e.g. anthracene
• CPC Class Codes: H10K 85/631 Amine compounds having at least two aryl rest on at least one amine-nitrogen atom, e.g. triphenylamine

Abstract

There is provided a process for vacuum drying. The process includes the steps of: depositing a liquid composition containing a film-forming material and at least one solvent onto a workpiece to form a wet layer; placing the wet layer on the workpiece into a vacuum chamber including a condenser; and treating the wet layer at a controlled temperature in the range of −25 to 80° C. and under an applied vacuum in the range of 10⁻⁶ to 1,000 Torr for a period of 1-100 minutes; wherein the condenser is maintained at a temperature at which the solvent will condense as a liquid at the applied vacuum.

Claims

1. A process for forming a layer of electroactive material, comprising:

providing a workpiece having at least one active area;

depositing a liquid composition comprising the electroactive material in a liquid medium onto the workpiece in the at least one active area, to form a wet layer, wherein the liquid medium comprises at least two liquid components, and at least one component has a boiling point of greater than 100°

C.;

placing the wet layer on the workpiece into a vacuum chamber having a condenser therein;

treating the wet layer on the workpiece at a controlled temperature in the range of 30°

to 60°

C. and at a pressure in the range of 10<sup>−

2</sup> to 1 Torr, for a first period of 5-15 minutes, to form a partially dried layer, wherein the condenser is maintained at a temperature at which the at least one component with a boiling point of greater than 100°

C. will condense as a liquid at the applied vacuum;

heating the partially dried layer to a temperature above 100°

C. for a second period of 1-50 minutes to form a dried layer,

wherein the dried layer has a substantially flat profile in the at least one active area.

2. The process of claim 1, wherein the dried layer has a thickness variation of less than +/−

10% over 90% of the at least one active area.

3. The process of claim 1, wherein the liquid composition is deposited by a technique selected from the group consisting of ink jet printing and continuous nozzle coating.

4. The process of claim 1, wherein the workpiece has a multiplicity of active areas.

5. The process of claim 4, wherein the electroactive material comprises a host material and a photoactive guest material corresponding to a first color, and the liquid composition is deposited in a first portion of the at least one active area.

6. The process of claim 5, wherein a second liquid composition comprising a second host material and a second photoactive guest material corresponding to a second color is deposited in a second portion of the at least one active area.

7. The process of claim 6, wherein a third liquid composition comprising a third host material and a third photoactive guest material corresponding to a third color is deposited in a third portion of the at least one active area.

8. The process of claim 1, wherein the condenser is a surface condenser.

9. The process of claim 1, wherein the condenser is maintained at a temperature below 20°

C.

10. The process of claim 1, wherein the condenser is maintained at a temperature in the range of −

15°

to 15°

C.

11. The process of claim 1, wherein the vacuum chamber further comprises means for removing condensed solvent from the chamber.

12. The process of claim 1, wherein the heating the partially dried layer comprises heating to a temperature of 110°

C.-150°

C. and the second period is 10-30 min.

13. The process of claim 1, wherein the electroactive material consists essentially of a hole injection material.

14. The process of claim 1, wherein the electroactive material consists essentially of a hole transport material.

15. A process for forming a layer of electroactive material, comprising:

providing a workpiece having at least one active area;

depositing an electroactive material in solution with at least one organic solvent onto the workpiece in the the at least one active area, to form a wet layer, wherein, the electroactive material and the at least one organic solvent each has a boiling point of less than 120°

C.;

placing the wet layer on the workpiece into a vacuum chamber having a condenser therein;

treating the wet layer on the workpiece at a controlled temperature in the range of −

25°

to 10°

C. at a pressure in the range of 1 Torr to 1,000 Torr, for a first period of 5-25 minutes, to form a partially dried layer, wherein the condenser is maintained at a temperature at which the solvent will condense as a liquid at the applied vacuum;

heating the partially dried layer to a temperature above 100°

C. for a second period of 1-50 minutes to form a dried layer,

wherein the dried layer has a substantially flat profile in the at least one active area.

16. The process of claim 15, wherein the wet layer on the workpiece is treated at a temperature in the range of −

10 to 0°

C., at a pressure in the range of 10 to 100 Torr, for a time of 5-15 minutes.

17. The process of claim 15, wherein the dried layer has a thickness variation of less than +/−

10% over 90% of the at least one active area.

18. The process of claim 15, wherein the workpiece has a multiplicity of active areas.