Methods of making displays
Methods of forming displays are described. The displays have zinc oxide row and column drivers integrated onto the same display substrate as zinc oxide pixel transistors and organic light emitting diodes. The organic light emitting diodes are prepared, at least in part, using a thermal transfer process from a donor sheet.
1. A method of preparing a display, the method comprising:
patterning a set of zinc oxide channel thin film transistor row and column drivers on a display substrate;
patterning a set of zinc oxide channel pixel thin film transistors on the display substrate, the pixel thin film transistors being in electrical contact with the thin film transistor row and column drivers; and
forming a set of organic light emitting diodes on the display substrate, each organic light emitting diode comprising a first electrode, a second electrode, and a light-emitting material positioned between the first electrode and the second electrode, wherein the forming of at least one organic light emitting diode comprises
providing a first electrode in electrical contact with at least one pixel thin film transistor;
preparing a first donor sheet comprising a first donor substrate and a first thermal transfer layer comprising a first light-emitting material;
transferring the first thermal transfer layer from the first donor sheet, wherein the first thermal transfer layer is transferred adjacent to the first electrode; and
depositing a second electrode, wherein the first thermal transfer layer is positioned between the first electrode and the second electrode.
2. The method of claim 1 , wherein the donor sheet further comprises a light-to-heat converting layer positioned between the donor substrate and the first transfer layer.
3. The method of claim 2 , wherein transferring the first thermal layer comprises heating the donor sheet with a radiation emitting source.
4. The method of claim 2 , wherein the donor sheet further comprises an interlayer positioned between the light-to-heat converting layer and the first thermal transfer layer.
5. The method of claim 1 , wherein the first electrode of the organic light emitting diode is in electrical contact with a source or drain electrode of at least one thin film transistor.
6. The method of claim 1 , further comprising depositing a buffer layer on a surface of the first electrode opposite the flexible display substrate, wherein both the first electrode and the buffer layer are positioned between the display substrate and the first transfer layer.
7. The method of claim 6 , further comprising depositing a charge transport layer, a charge blocking layer, a charge injection layer, or a combination thereof on the buffer layer.
8. The method of claim 1 , wherein the donor sheet further comprises a second thermal transfer layer comprising a charge transport material, a charge injection material, a charge blocking material, a buffer material, or a combination thereof and wherein the second thermal transfer layer is transferred with the first thermal transfer layer.
9. The method of claim 1 , further comprising
preparing a second donor sheet comprising a second donor substrate and a second thermal transfer layer;
transferring the second thermal transfer layer from the second donor sheet, wherein the second transfer layer is positioned between the first electrode and the second electrode.
10. The method of claim 9 , wherein the second thermal layer comprises a charge transport material, a charge blocking material, a charge injection material, a buffer material, or a combination thereof.
11. The method of 9 , wherein transferring the first thermal transfer layer comprises a first transfer to a first region between the first and second electrodes and transferring the second transfer layer comprises a second transfer to a second region between the first and second electrodes, wherein the first region does not overlap with the second region.
12. The method of claim 11 , wherein the second thermal transfer layer comprises a second light-emitting material that emits light in a wavelength range different than the first light-emitting material.
13. The method of claim 9 , wherein transferring the first thermal transfer layer comprises a first transfer to a first region between the first and second electrodes and transferring the second transfer layer comprises a second transfer to a second region between the first and second electrodes, wherein the first region overlaps with the second region.
14. The method of claim 13 , wherein the second thermal transfer layer comprises a charge transport material, a charge blocking material, a charge injection material, a buffer material, or a combination thereof.
15. The method of claim 1 , wherein patterning the set of zinc oxide channel thin film transistor row and column drivers and patterning the set of zinc oxide channel pixel thin film transistors on the display substrate comprises forming by photolithography.
16. The method of claim 1 , wherein patterning the set of zinc oxide channel thin film transistor row and column drivers and patterning the set of zinc oxide channel pixel thin film transistors on the display substrate comprises using a polymeric aperture mask.
17. The method of claim 1 , further comprising patterning an encapsulant layer over the row and column drivers and the pixel thin film transistors.
18. The method of claim 1 , further comprising depositing a second layer between the first and second electrode, the second layer comprising a charge transfer material, a charge blocking material, a charge injection material, a buffer material, or a combination thereof.
19. The method of claim 18 , wherein the second layer is patterned using a polymeric aperture mask.
20. The method of claim 1 , wherein the first electrode is transparent.
21. The method of claim 1 , wherein the second electrode is transparent.
22. The method of claim 1 , wherein the patterning occurs at a temperature no greater than 100° C.
23. The method of claim 1 , wherein the display substrate is polymeric.