Method and apparatus for coating an organic thin film on a substrate from a fluid source with continuous feed capability

Abstract

A method for coating a thin film of a non-polymeric compound on a substrate by providing a mixture of the non-polymeric compound and a fluid carrier. This mixture is then pumped into the interior of a heated evaporation box having an internal temperature sufficient to convert substantially all of the non-polymeric compound and fluid carrier to a gaseous form. The non-polymeric compound and fluid carrier are then removed from the evaporation box via exit slit in the evaporation box. Adjacent to the exit slit, and maintained in a vacuum, is a substrate upon which the non-polymeric compound condenses. The substrate is in motion, for example on a web roller, thereby allowing a continuous coating of the non-polymeric compound to be applied to the substrate.

1 ) a method for coating a thin film of a non-polymeric compound on a substrate comprising the steps of: 
 a. providing a mixture of said non-polymeric compound and a fluid carrier,    b. pumping said mixture to the interior of a heated evaporation box,    c. exposing said mixture to a temperature within said heated evaporation box sufficient to convert substantially all of said non-polymeric compound and fluid carrier to a gaseous form,    d. removing said non-polymeric compound and fluid carrier in said gaseous form through an exit slit in said evaporation box, and    e. condensing said non-polymeric compound on a substrate maintained in a vacuum and in motion relative to said exit slit in said evaporation box.    
     
     
         2 ) The method of  claim 1  further comprising the step of maintaining the substrate at a temperature sufficiently high so that the fluid carrier does not condense on the substrate.  
     
     
         3 ) The method of  claim 1  further comprising the step of maintaining the substrate at a temperature sufficiently high such that fluid carrier in contact with the substrate evaporates.  
     
     
         4 ) The method of  claim 1  further comprising the steps of 
 a. maintaining the substrate at a temperature sufficiently low to allow both the fluid carrier and the non-polymeric compound to condense on the substrate at the exit slit of the evaporation box and    b. subsequently increasing the temperature of the substrate to a temperature sufficient to cause the fluid carrier to evaporate.    
     
     
         5 ) The method of  claim 1  further comprising the step of capturing the fluid carrier and subsequently recycling the fluid carrier to provide additional mixture of the non-polymeric compound with the fluid carrier.  
     
     
         6 ) The method of  claim 5  further comprising providing a cold trap in front of a pump used to provide said vacuum to condense the fluid carrier.  
     
     
         7 ) The method of  claim 1  wherein said substrate is provided on a web roller.  
     
     
         8 ) The method of  claim 1  wherein said box temperature is provided as greater than 100° C.  
     
     
         9 ) The method of  claim 1  wherein the non-polymeric compound is selected as an organic material.  
     
     
         10 ) The method of  claim 9  wherein said organic material is selected from the group consisting of OLED materials and metal (8-hydroxyquinoline) chelate.  
     
     
         11 ) The method of  claim 1  wherein the non-polymeric compound is selected as an inorganic material.  
     
     
         12 ) The method of  claim 1  wherein the solvent is selected from the group consisting of straight chain and branched alcohols and diols, amides, dimethylsulfoxide, N-methylpyrrolidinone, toluene, ketones, esters, halogenated solvents, 1-hexanol, and combinations thereof.  
     
     
         13 ) The method of  claim 1  wherein the non-polymeric compound is selected as a mixture of organic and inorganic materials.  
     
     
         14 ) The method of  claim 1  wherein said exit slit is provided as a series of exit slits.  
     
     
         15 ) The method of  claim 1  wherein said mixture is atomized into a fine spray inside of said evaporation box.  
     
     
         16 ) The method of  claim 15  wherein said mixture is atomized into a fine spray using an ultrasonic tip or a fuel injector.  
     
     
         17 ) The method of  claim 1  further comprising the step of agitating the mixture in a source reservoir prior to introducing the mixture to the evaporation box.  
     
     
         18 ) The method of  claim 17  wherein said agitation is provided by ultrasonic agitation, mechanical vibration, magnetic stirring, and combinations thereof.  
     
     
         19 ) A method for coating a thin film of a metal (8-hydroxyquinoline) chelate on a substrate comprising the steps of: 
 a. providing a mixture of metal (8-hydroxyquinoline) chelate and 1-hexanol,    b. pumping said mixture to the interior of a heated evaporation box,    c. exposing said mixture to a temperature within said heated evaporation box sufficient to convert substantially all of said metal (8-hydroxyquinoline) chelate and 1-hexanol to a gaseous form,    d. removing the metal (8-hydroxyquinoline) chelate and 1-hexanol in a gaseous form through an exit slit in the evaporation box, and    e. condensing the metal (8-hydroxyquinoline) chelate on a substrate maintained in a vacuum and in motion relative to said exit slit in said evaporation box.    
     
     
         20 ) The method of  claim 19  further comprising the step of maintaining the substrate at a temperature sufficiently high so that the 1-hexanol does not condense on the substrate.  
     
     
         21 ) The method of  claim 19  further comprising the step of maintaining the substrate at a temperature sufficiently high so that any 1-hexanol in contact with the substrate evaporates.  
     
     
         22 ) The method of  claim 19  further comprising the steps of 
 a. maintaining the substrate at a temperature sufficiently low to allow both the metal (8-hydroxyquinoline) chelate and 1-hexanol to condense on the substrate at the exit slit of the evaporation box and    b. subsequently increasing the temperature of the substrate to a temperature sufficient to cause the 1-hexanol to evaporate.    
     
     
         23 ) The method of  claim 1  wherein said non-polymeric compound forms part or all of a light emitting device.  
     
     
         24 ) The method of  claim 1  wherein said non-polymeric compound forms part or all of a thin film transistor.  
     
     
         25 ) The method of  claim 1  wherein said non-polymeric compound forms part or all of a photovoltaic device.