Cross-linkable fluorinated photopolymer
A photosensitive composition comprises a fluorinated solvent, a photo-acid generator and a copolymer. The copolymer comprises at least three distinct repeating units, including a first repeating unit having a fluorine-containing group, a second repeating unit having an acid-catalyzed cross-linkable group, and a third repeating unit having a sensitizing dye. The composition is useful in the fabrication of electronic devices, especially organic electronic and bioelectronic devices.
1. A photosensitive composition comprising:
a fluorinated solvent;
a photo-acid generator; and
a copolymer comprising at least three distinct repeating units, including a first repeating unit having a fluorine-containing group, a second repeating unit having an acid-catalyzed cross-linkable group, and a third repeating unit having a sensitizing dye.
2. The photosensitive composition of claim 1 wherein the copolymer has a total fluorine content in a range of 15 to 60% by weight.
3. The photosensitive composition of claim 1 wherein the acid-catalyzed cross-linkable group is an epoxide.
4. The photosensitive composition of claim 1 wherein the fluorine-containing group is a fluoroalkyl.
5. The photosensitive composition of claim 1 wherein the solvent is a hydrofluoroether.
6. The photosensitive composition of claim 1 wherein the sensitizing dye is a coumarin or anthracene having a light absorption peak in a range of 300 to 450 nm.
7. The photosensitive composition of claim 1 wherein the photo-acid generator is non-ionic and has one or more fluorine atoms.
8. The photosensitive composition of claim 1 wherein the photo-acid generator is covalently attached to the copolymer, which further comprises a photo-acid generating repeating unit.
9. The photosensitive composition of claim 8 wherein the photo-acid generating repeating unit is selected so that, upon activation of the photo-acid generator, an acid portion remains attached to the copolymer and a release portion includes a fluorinated group.
10. A method of patterning a device, comprising:
forming a photopolymer layer on a device substrate, the photopolymer layer including a photo-acid generator and a copolymer, wherein the copolymer comprises at least three distinct repeating units, including a first repeating unit having a fluorine-containing group, a second repeating unit having an acid-catalyzed cross-linkable group, and a third repeating unit having a sensitizing dye;
exposing the photopolymer layer to patterned radiation to form an exposed photopolymer layer; and
contacting the exposed photopolymer layer with a developing agent to remove unexposed photopolymer, thereby forming a developed structure having a first pattern of exposed photopolymer covering the substrate and a complementary second pattern of uncovered substrate corresponding to the unexposed photopolymer.
11. The method of claim 10 wherein the developing agent comprises at least 50% by volume of a hydrofluoroether solvent.
12. The method of claim 10 wherein the device substrate comprises a support and a layer of active organic material, and wherein the photopolymer layer is in contact with the layer of active organic material.
13. The method of claim 10 wherein the first pattern of photopolymer forms at least a portion of a gate dielectric in an organic thin film transistor device.
14. The method of claim 10 wherein the first pattern of photopolymer forms a plurality of wells capable of containing a display material.
15. The method of claim 14 further comprising providing display material into one or more of the plurality of wells, wherein the display material is a color filter material, a liquid crystal material, an electrophoretic material, an organic light-emitting material or a semiconductor nanoparticle material.
16. The method of claim 10 wherein the first pattern of photopolymer forms at least a portion of a barrier layer in a water sensitive or bioelectronic device.
17. The method of claim 10 wherein the photo-acid generator is covalently attached to the copolymer, which further comprises a photo-acid generating repeating unit.
18. An article comprising a layer of a copolymer having at least three distinct repeating units, including a first repeating unit having a fluorine-containing alkyl group, a second repeating unit having an alkyl ether group that is cross linked to an alkyl ether group of another second repeating unit, and a third repeating unit having a sensitizing dye that has a light absorption peak in a range of 300 to 450 nm, wherein the copolymer has a total fluorine content in a weight range of 15 to 60%.
19. The article of claim 18 wherein the article is an organic thin film transistor device, an OLED device, a display device, a bioelectronic device or a lighting device.