Methods for depositing nanomaterial, methods for fabricating a device, and methods for fabricating an array of devices
View Patent ↗A method comprising depositing an ink comprising a nanomaterial and a liquid vehicle from a micro-dispenser onto a layer of a device is disclosed. A method comprising depositing an ink comprising a nanomaterial and a liquid vehicle from a micro-dispenser onto a material capable of transporting charge in a predetermined arrangement is also disclosed. Methods for fabricating devices including nanomaterials are also disclosed. In certain preferred embodiments, the nanomaterial comprises semiconductor nanocrystals. In certain preferred embodiments, a micro-dispenser comprises an inkjet printhead.
1. A method for making a light-emitting device including an emissive material including a nanomaterial comprising quantum confined semiconductor nanocrystals that emit light having a predetermined wavelength comprising:
providing a substrate including a first electrode,
disposing a first layer over the substrate including the first electrode;
depositing an ink comprising the nanomaterial comprising the quantum confined semiconductor nanocrystals and a liquid vehicle over a surface of the first layer from a micro-dispenser in a predetermined arrangement; and
disposing a second electrode over the predetermined arrangement,
wherein the first layer comprises a material which is at least partially soluble in the liquid vehicle, wherein at least a portion of the nanomaterial is at least temporarily mixed in a portion of the material that dissolves in the ink, and wherein the liquid vehicle is removed such that the nanomaterial phase separates to form a layer of nanomaterial at the surface of the first layer.
2. A method in accordance with claim 1 wherein the first layer comprises a material capable of transporting holes.
3. A method in accordance with claim 1 wherein the micro-dispenser comprises an inkjet printhead and the ink is deposited by inkjet processing.
4. A method in accordance with claim 3 further comprising removing the liquid vehicle from the ink and disposing a second layer comprising a material capable of transporting electrons over the predetermined arrangement before disposing the second electrode.
5. A method in accordance with claim 1 wherein each of the first layer and the nanomaterial layer of the device is formed by inkjet processing.
6. A method in accordance with claim 4 wherein each of the first layer, the nanomaterial layer, and the second layer of the device is formed by inkjet processing.
7. A method in accordance with claim 1 further comprising disposing one or more additional layers before disposing the second electrode layer.
8. A method in accordance with claim 7 wherein each of the first layer, the nanomaterial layer, the one or more additional layers, and second electrode layer of the device is formed by inkjet processing.
9. A method in accordance with claim 7 further comprising packaging the device.
10. A method in accordance with claim 9 wherein a desiccant material is included in the device before the packaging is completed.
11. A method in accordance with claim 1 further comprising disposing a layer comprising a hole injection material over the substrate before the first layer is disposed over the substrate.
12. A method in accordance with claim 11 wherein all layers of the device other than the first electrode are formed by inkjet processing.
13. A method in accordance with claim 1 , wherein the layer comprising the nanomaterial comprises two or more nanomaterials, wherein each nanomaterial comprises quantum confined semiconductor nanocrystals and the emission characteristics of each nanomaterial are distinguishable from those of another nanomaterial, and wherein the two or more nanomaterials are patterned into distinct regions.
14. A method in accordance with claim 1 wherein the liquid vehicle is removed from the ink such that at least a portion of the material and the nanomaterial remain mixed.