Light emitting device, light emitting apparatus provided with a light emitting device, and method of manufacturing a light emitting device
View Patent ↗The present disclosure aims to provide a light-emitter having a favorable luminescence property, a light-emitting device having the light-emitter, and a method of manufacturing the light-emitter. Specifically, the light-emitter has the following structure. A hole injection layer and a light-emitting layer are layered between a first electrode and a second electrode which are transparent, and a light-emitting layer exists in an area defined by a bank. Thus, organic EL elements are formed. The hole injection layer has a recess in an upper surface of the area defined by the bank. An upper peripheral edge of the recess in the hole-injection layer is covered with a portion of the bank.
1. A double-sided light-emitter that emits light from both sides thereof, comprising:
a first electrode;
a laminate disposed on the first electrode that includes a charge injection transport layer and a functional layer including a light-emitting layer;
a second electrode disposed on the laminate; and
a bank that is insulative and defines an area in which the light-emitting layer is to be formed, wherein
the first electrode and the second electrode are transparent electrodes,
the charge injection transport layer has a recess in an upper surface of the area defined by the bank,
an upper peripheral edge of the recess is covered with a portion of the bank, the upper peripheral edge of the recess comprising at least a portion of an inner side surface of the recess,
a part of the light-emitting layer is interposed between the second electrode and the upper peripheral edge of the recess,
the part of the light-emitting layer is interposed between the second electrode and the portion of the bank, and undergoes charge injection from the second electrode, and
the portion of the bank is interposed between the upper peripheral edge of the recess and the part of the light-emitting layer.
2. The light-emitter of claim 1 , wherein
the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride.
3. The light-emitter of claim 2 , wherein
the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and
the hole transport layer is interposed between the hole injection layer and the light-emitting layer.
4. The light-emitter of claim 1 , wherein
the transparent electrodes are made from ITO or IZO.
5. The light-emitter of claim 1 , wherein
a metal thin film that is semi-transparent or transparent is layered on at least one of the first electrode and the second electrode.
6. The light-emitter of claim 5 , wherein
the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness of 3 nm to 30 nm.
7. The light-emitter of claim 1 , wherein
the charge injection transport layer is made from a material that is eroded when exposed to a liquid used for forming the bank.
8. The light-emitter of claim 1 , wherein
the liquid is water or a TMAH solution.
9. The light-emitter of claim 1 , wherein
the portion of the bank reaches an inner bottom surface of the recess, and a side surface of the bank slopes upward from the inner bottom surface of the recess to a top surface of the bank.
10. The light-emitter of claim 1 , wherein
the portion of the bank is out of contact with an inner bottom surface of the recess.
11. The light-emitter of claim 1 , wherein
the bank includes an insulating material.
12. The light-emitter of claim 1 , wherein
the light-emitting layer comprises an organic EL layer.
13. The light-emitter of claim 1 , wherein
the charge injection transport layer extends laterally along a bottom surface of the bank.
14. The light-emitter of claim 1 , wherein
the upper peripheral edge of the recess comprises a convex portion composed of a part of the upper surface of the charge injection transport layer in which the recess is not formed, and the portion of the inner side surface of the recess.
15. The light-emitter of claim 1 , wherein
the second electrode is a cathode,
the laminate includes an electron transport layer interposed between the light-emitting layer and the second electrode, and
electrons injected from the second electrode are transported to the functional layer including the light-emitting layer via the electron transport layer.
16. A light-emitting device comprising a plurality of light-emitters that are each the light-emitter of claim 1 .
17. A method of manufacturing a double-sided light-emitter emitting light from both sides thereof and including a first electrode, a laminate disposed on the first electrode that includes a charge injection transport layer and a functional layer including a light-emitting layer, a second electrode disposed on the laminate, and a bank that defines an area in which the light-emitting layer is to be formed, the method comprising:
forming the first electrode from a transparent electrode;
forming the charge injection transport layer;
forming a bank material layer that forms the bank on the charge injection transport layer;
removing a portion of the bank material layer to partially expose the charge injection transport layer;
heat-treating a remaining portion of the bank material layer;
forming the functional layer on an exposed surface of the charge injection transport layer after the heat treatment; and
forming the second electrode from a transparent electrode, wherein
the charge injection transport layer is made from a material that is eroded when exposed to a liquid used while the charge injection transport layer is partially exposed, the charge injection transport layer having a recess in the exposed surface thereof so that an inner bottom surface of the recess is lower than a bottom surface of a remaining portion of the bank material layer, the recess being formed by the exposed surface eroded by the liquid, the remaining portion of the bank material layer being made fluid so that the bank material layer extends to cover an upper peripheral edge of the recess, the upper peripheral edge of the recess comprising at least a portion of an inner side surface of the recess.
18. The method of claim 17 , wherein
the charge injection transport layer is a hole injection layer made from one of a metal oxide, a metal nitride, and a metal oxynitride.
19. The method of claim 18 , wherein
the functional layer includes a hole transport layer that transports holes from the hole injection layer to the light-emitting layer, and
the hole transport layer is interposed between the hole injection layer and the light-emitting layer.
20. The method of claim 17 , wherein
the transparent electrodes are made from ITO or IZO.
21. The method of claim 17 , wherein
a metal thin film that is semi-transparent or transparent is layered on at least one of the first electrode and the second electrode.
22. The method of claim 21 , wherein
the metal thin film contains any material selected from the group consisting of Ag, Mg, Al, Pt, Pd, Au, Ni, Ir and Cr, and has a thickness falling within a range of 3 nm to 30 nm.
23. The method of claim 22 , wherein
the metal thin film is formed by vacuum forming.