Protective coatings for organic electronic devices made using atomic layer deposition and molecular layer deposition techniques
Coatings are applied on a flexible substrate using atomic layer deposition and molecular layer deposition methods. The coatings have thickness of up to 100 nanometers. The coatings include layers of an inorganic material such as alumina, which are separated by flexibilizing layers that are deposited with covalent chemical linkage to the inorganic material and which are one or more of silica deposited by an atomic layer deposition process; an organic polymer that is deposited by a molecular layer deposition process, or a hybrid organic-inorganic polymer that is deposited by an molecular layer deposition process.
1. A coated flexible substrate comprising a flexible substrate having a coating, wherein the coating includes
a) at least two layers of an inorganic material other than silica, each of said layers having a thickness of from 10 to 50 angstroms and being produced by an atomic layer deposition process, and
b) a flexibilizing layer interposed between each adjacent pair of layers of the inorganic material, the flexibilizing layer having a total thickness of from 10 to 75% of the thickness of the thicker of said adjacent pair of layers of the inorganic material, wherein the flexibilizing layer is a hybrid organic-inorganic polymer that is deposited by a molecular layer deposition process, wherein the hybrid organic-inorganic polymer is a linear or branched chain structure having metal or semi-metal repeating units which alternate with organic units, the hybrid organic-inorganic polymer having the structure
[-M-Z—R—Z—] n
wherein M represents a metal or semi-metal atom selected from, magnesium, calcium, strontium, barium, titanium, zirconium, manganese, iron, nickel, cobalt, zinc, cadmium, aluminum, gallium, indium, germanium, tin, lead, antimony or bismuth, each Z is independently a linking group that contains at least one a heteroatom, R represents a hydrocarbyl or inertly substituted hydrocarbyl group and n represents the degree of polymerization.
2. The coated flexible substrate of claim 1 wherein the inorganic material is alumina and the metal M is aluminum.
3. The coated flexible substrate of claim 1 , wherein the flexible substrate is a flexible organic light emitting device.