Process for forming an electroactive layer
View Patent ↗There is provided a process for forming a layer of electroactive material having a substantially flat profile. The process includes: providing a workpiece having at least one active area; depositing a liquid composition including the electroactive material onto the workpiece in the active area, to form a wet layer; treating the wet layer on the workpiece at a controlled temperature in the range of −25 to 80° C. and under a vacuum in the range of 10 −6 to 1,000 Torr, for a first period of 1-100 minutes, to form a partially dried layer; heating the partially dried layer to a temperature above 100° C. for a second period of 1-50 minutes to form a dried layer.
1. A process for forming a layer of electroactive material, comprises:
providing a workpiece having at least one active area;
depositing a liquid composition comprising the electroactive material onto the workpiece in the active area, to form a wet layer;
treating the wet layer on the workpiece at a controlled temperature in the range of −25 to 80° C. and under a vacuum in the range of 10 −6 to 1,000 Torr, for a first period of 1-100 minutes, to form a partially dried layer;
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 active area; and wherein the vacuum is applied by means of a pump selected from the group consisting of dry vacuum pumps, turbo pumps, rotary vane vacuum pumps, oil diffusion pumps, cryogenic pumps, and sorption pumps.
2. The process of claim 1 , wherein the dried layer has a thickness variation of less than +/−10% over 90% of the 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 active areas.
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 active areas.
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 active areas.
8. The process of claim 1 , wherein the electroactive material consists essentially of a hole injection material.
9. The process of claim 1 , wherein the electroactive material consists essentially of a hole transport material.
10. The process of claim 1 , wherein the wet layer on the workpiece is treated at a temperature in the range of 20-80° C., at a pressure in the range of 10 −2 to 10 Torr, for a time of 5-25 minutes.
11. The process of claim 1 , wherein the wet layer on the workpiece is treated at a temperature in the range of 30-60° C., at a pressure in the range of 10 −2 to 1 Torr, for a time of 5-15 minutes.
12. The process of claim 1 , wherein the wet layer on the workpiece is treated at a temperature in the range of −25 to 10° C., at a pressure in the range of 1 to 1000 Torr, for a time of 5-25 minutes.
13. The process of claim 1 , 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.
14. The process of claim 1 , wherein the vacuum is in the range of 10 −4 to 10 −6 Torr.
15. The process of Claim 1 , wherein the pump is a turbomolecular pump.