Printing of organic electronic devices
The composition of a organic (e.g. conducting polymer) solution is reformulated and the device upon which the organic solution is to be deposited is plasma treated to provide a more uniform and flat drying profile for the resulting dried film. This reformulation and treatment induces a more uniform and flatter profile when the reformulated organic solution is allowed to dry into a film on the treated device.
1 . A method of fabricating an organic electronic device, comprising:
forming a patterned lower electrode layer on a substrate, said lower electrode layer having an exposed deposition surface;
fabricating a photo-resist layer upon said lower electrode layer, said photo-resist layer patterned to define pockets on said deposition surface;
treating said photo-resist layer and said deposition surface to raise the surface energy of said deposition surface and lower the surface energy of said photo-resist layer;
reformulating an organic solution by mixing a base organic solution with humectants;
depositing drops of said reformulated solution into each said pocket; and
allowing each drop of said drops to dry into an organic layer, said organic layer having a substantially flat and uniform profile.
2 . The method of claim 1 , wherein said treating includes applying a fluorinating plasma process.
3 . The method of claim 2 , wherein said fluorinating plasma process uses sulfur hexafluoride.
4 . The method of claim 1 , wherein said organic electronic device is an organic light emitting diode (OLED) device.
5 . The method of claim 4 , wherein said lower electrode layer functions as an anode.
6 . The method of claim 5 , wherein said organic layer is a conducting polymer layer.
7 . The method of claim 6 , further comprising fabricating an emissive layer above said conducting polymer layer, said emissive layer capable of emitting light upon charge recombination.
8 . The method of claim 6 , wherein said base organic solution is a PEDOT:PSS solution.
9 . The method of claim 8 , wherein the ratio of PEDOT to PSS is one part to six parts, respectively.
10 . The method of claim 9 , wherein reformulating an organic solution includes mixing the base organic solution with the humectants and water.
11 . The method of claim 10 , wherein the ratio of base organic solution to humectants to water is thirty parts to forty parts to thirty parts, respectively.
12 . The method of claim 1 , wherein said device is an organic transistor.
13 . The method of claim 1 , wherein said device is an organic solar cell.
14 . The method of claim 1 , wherein said humectants are at least one of glycols and glycol derivatives.
15 . A method according to clam 1 , wherein the reformulated organic solution consists essentially of the base organic solution and the humectants and water.
16 . A method according to clam 1 , wherein the humectants include one or more of propanediol, a glycol, glycerol, ether or a combination thereof.
17 . A method according to clam 1 , wherein the humectants include a polyol.
18 . The method of claim 17 , wherein the polyol includes a propanediol, a glycol, glycerol or a combination thereof.
19 . The method of claim 17 , wherein the reformulated organic solution further includes water.