Method to print organic electronics without changing its properties

Abstract

Method for high throughput, highly reproducible, direct write plasma jet deposition of organic electronic materials through nozzles containing non-concentric tubes with inner tube having higher dielectric constant and/or higher wall thickness than the outer tube, so that the inner tube containing the aerosol of organic electronic materials is shielded from the outer tube containing plasma and the organic electronics is focused at the outlet of the nozzle through the after-glow region of the atmospheric pressure plasma. Ensuring reproducibility of the method for printing organic electronic materials by removing the contaminants and residues in inner tube using reactive gas and generating a plasma discharge at a potential significantly higher than the operating potential for printing so that the plasma is generated in both the inner and outer tube for dielectric barrier discharge plasma jet based cleaning of the nozzle.

1 . A plasma jet printer for high throughput direct write printing of conducting electronic materials without changing its material properties, comprising:
 a nozzle with two non-concentric tubes, with inner tube having different thickness and/or higher dielectric constant than then outer tube;   a inner tube with higher thickness and/or higher dielectric constant for carrying aerosol of electronic materials and for shielding the aerosol from getting exposed to high energy plasma species surrounded in the outer tube;   a outer tube with lower thickness and/or dielectric constant than the inner tube and that carries a gas for creating a plasma discharge inside the outer tube;   a inner and outer tube having different axis along the length of the tube;   a outer tube with the outer walls in conical shape to create a high pressure and turbulence at the outlet of the nozzle;   a electrode assembly on the outer nozzle connected to a high voltage power supply for creating a plasma discharge to be confined between the outer wall of the inner tube and the inner wall of the outer tube;   a nebulizer for generating the aerosol of organic electronic materials;   a tube for transporting the aerosol containing organic electronic materials to the inner tube of the nozzle;   a tube for carrying gas through the outer nozzle for generating plasma discharge;   a nozzle outlet where the aerosol containing organic electronics enters the after-glow discharge of the plasma for directing the organic electronic materials to the substrate;   wherein the after-glow region of the plasma discharge from the nozzle has the ability to direct and print the electronic materials without changing the chemical structure and bonding nature of the organic materials due to plasma;   wherein the reproducibility of organic electronic materials printing is ensured by reactive plasma jet cleaning of the inner nozzle by passing reactive gases and generating a plasma at significantly higher potential than the operating potential for printing so that the dielectric barrier discharge plasma is generated both in the inner and outer tubes that remove the residues and contaminants formed during deposition.   
     
     
         2 . A device according to  claim 1 , wherein the organic electronic materials used for deposition can be used any of the following cathode materials, anode materials, electron injection layer, electron transporting layer, exciton/hole blocking layer, emissive layer, exciton/electron blocking layer, hole transporting layer, hole injection layer and anode material. 
     
     
         3 . A device according to  claim 1 , wherein the reproducibility of the organic electronic material printing can be sustained by cleaning of the inner tube and the nozzle using plasma jet cleaning wherein the reactive gases can be fed during cleaning process with significantly higher applied potential than that used for printing so that the plasma discharge is created both in the inner tube and in the outer tube that helps remove the contaminants and residues attached to the inner wall of the inner tube during printing. 
     
     
         4 . A device according to  claim 1 , wherein the plasma jet printer nozzle can be used for printing organic electronics by exposing the aerosol containing organic materials only to the after-glow region outside the nozzle and shielding from the outer tube containing plasma species by operating at a lower applied potential and the cleaning of the nozzle is carried out by generating plasma in both the inner and outer tube by operating at a significantly higher potential.