Process for forming an electroactive layer

Abstract

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.

What is claimed is: 
     
         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. 
     
     
         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 14 , 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. 
     
     
         16 . The process of  claim 15 , wherein the pump is a turbomolecular pump. 
     
     
         17 . An electronic device having at least one active area comprising an anode, a cathode, and an electroactive layer therebetween, wherein the electroactive layer is formed by liquid deposition and has a substantially flat profile. 
     
     
         18 . The device of  claim 17 , wherein the electroactive layer is a photoactive layer. 
     
     
         19 . The device of  claim 18 , wherein the electroactive layer is a light-emitting layer. 
     
     
         20 . The device of  claim 17 , wherein the electroactive layer is a hole transport layer. 
     
     
         21 . The device of  claim 17 , wherein the electroactive layer is a hole injection layer. 
     
     
         22 . The device of  claim 17 , wherein the active area is divided into subpixel areas by a physical containment structure, and the electroactive layer is in the subpixel areas.