Method of manufacturing perovskite light emitting device by inkjet printing

1. A method of fabricating a perovskite light emitting device, wherein the method comprises the following steps:

providing a substrate;

providing a first electrode disposed over the substrate;

providing a bank structure disposed over the substrate, wherein the bank structure is patterned so as to define at least one sub-pixel on the substrate;

providing a first transport layer ink, wherein the first transport layer ink comprises at least one solvent and at least one first charge transport material mixed in the at least one solvent;

depositing the first transport layer ink into the at least one sub-pixel over the first electrode using a method of inkjet printing;

vacuum drying the first transport layer ink inside a vacuum drying chamber to assemble a first transport layer over the first electrode in the at least one sub-pixel;

annealing the first transport layer;

providing a perovskite ink, wherein the perovskite ink comprises at least one solvent and at least one perovskite light emitting material mixed in the at least one solvent;

depositing the perovskite ink into the at least one sub-pixel over the first transport layer using a method of inkjet printing;

vacuum drying the perovskite ink inside a vacuum drying chamber to assemble a perovskite emissive layer over the first transport layer in the at least one sub-pixel;

annealing the perovskite emissive layer; and

depositing a second electrode over the perovskite emissive layer using a method of vapour deposition.

2. The method of claim 1 , wherein during the step of vacuum drying the first transport layer ink inside a vacuum drying chamber to assemble a first transport layer over the first electrode in the at least one sub-pixel, the ambient temperature inside the vacuum drying chamber is 50° C. or less, optionally 30° C. or less.

3. The method of claim 1 , wherein the thickness of the first transport layer is in the range of 10 nm to 80 nm.

4. The method of claim 1 , wherein the first transport layer is a cross-linked layer.

5. The method of claim 1 , wherein the step of annealing the first transport layer is performed in a different chamber to the step of vacuum drying the first transport layer ink inside a vacuum drying chamber to assemble a first transport layer over the first electrode in the at least one sub-pixel.

6. The method of claim 1 , wherein during the step of vacuum drying the perovskite ink inside a vacuum drying chamber to assemble a perovskite emissive layer over the first transport layer in the at least one sub-pixel, the pressure inside the vacuum drying chamber is reduced to less than or equal to 0.0001 mbar.

7. The method of claim 1 , wherein during the step of vacuum drying the perovskite ink inside a vacuum drying chamber to assemble a perovskite emissive layer over the first transport layer in the at least one sub-pixel, the ambient temperature inside the vacuum drying chamber is 50° C. or less, optionally 30° C. or less.

8. The method of claim 1 , wherein the perovskite ink comprises at least one perovskite light emitting material mixed in the at least one solvent at a concentration by weight in the range of 0.01 wt. % to 10 wt. %.

9. The method of claim 1 , wherein the thickness of the assembled perovskite emissive layer is in the range of 15 nm to 150 nm.

10. The method of claim 1 , wherein the length of the at least one sub-pixel is in the range of 100 μm to 250 μm, and the width of the at least one sub-pixel is in the range of 40 μm to 80 μm.

11. The method of claim 1 , wherein the step of annealing the perovskite emissive layer is performed in a different chamber to the step of vacuum drying the perovskite ink inside a vacuum drying chamber to assemble a perovskite emissive layer over the first transport layer in the at least one sub-pixel.

12. The method of claim 1 , wherein after the step of providing a bank structure disposed over the substrate, wherein the bank structure is patterned so as to define at least one sub-pixel on the substrate, but before the step of providing a first transport layer ink, wherein the first transport layer ink comprises at least one solvent and at least one first charge transport material mixed in the at least one solvent, the method further comprises the following steps:

providing a first injection layer ink, wherein the first injection layer ink comprises at least one solvent and at least one first charge injection material mixed in the at least one solvent;

depositing the first injection layer ink into the at least one sub-pixel over the first electrode using a method of inkjet printing;

vacuum drying the first injection layer ink inside a vacuum drying chamber to assemble a first injection layer over the first electrode in the at least one sub-pixel; and

annealing the first injection layer.

13. The method of claim 12 , wherein the thickness of the first injection layer is in the range of 10 nm to 80 nm.

14. The method of claim 12 , wherein during the step of vacuum drying the first injection layer ink inside a vacuum drying chamber to assemble a first injection layer over the first electrode in the at least one sub-pixel, the ambient temperature inside the vacuum drying chamber is 50° C. or less, optionally 30° C. or less.

15. The method of claim 12 , wherein the step of annealing the first injection layer is performed in a different chamber to the step of vacuum drying the first injection layer ink inside a vacuum drying chamber to assemble a first injection layer over the first electrode in the at least one sub-pixel.

16. The method of claim 12 , wherein after the step of annealing the perovskite emissive layer, but before the step of depositing a second electrode over the perovskite emissive layer using a method of vapour deposition, the method further comprises the step of depositing a second injection layer over the perovskite emissive layer using a method of vapour deposition.

17. The method of claim 12 , wherein after the step of annealing the perovskite emissive layer, but before the step of depositing a second electrode over the perovskite emissive layer using a method of vapour deposition, the method further comprises the step of depositing a second transport layer over the perovskite emissive layer using a method of vapour deposition.

18. A perovskite light emitting device, wherein the perovskite light emitting device is fabricated by the method of claim 1 .

19. A perovskite light emitting device, wherein the perovskite light emitting device is fabricated by the method of claim 1 , such that it is a standard perovskite light emitting device.

20. A perovskite light emitting device, wherein the perovskite light emitting device is fabricated by the method of claim 1 , such that it is an inverted perovskite light emitting device.