Electroluminescence element and method of manufacturing electroluminescence element
A method of manufacturing an electroluminescence element according to an embodiment of the present invention includes forming a first electrode on a substrate, forming a first electron transport layer in contact with the first electrode, forming a first insulating layer having an opening in a region overlapping with the first electrode, forming a second electron transport layer includes metal oxide semiconductor by applying a composition to the opening and removing a solvent after application, forming a light emitting layer overlapping with the second electron transport layer, the light emitting layer containing an electroluminescent material, forming a second electrode in a region overlapping with the light emitting layer.
1 . A method of manufacturing an inverted stack electroluminescence element, the method comprising:
forming a first electrode on a substrate;
forming a first electron transport layer in contact with the first electrode;
forming a first insulating layer having an opening in a region overlapping with the first electrode;
forming a second electron transport layer including metal oxide semiconductor by applying a liquid composition to the opening and removing a solvent by thermal treatment after application, wherein a specific resistance of the second electron transport layer is in the range of 10 2 Ω·cm to 10 6 Ω·cm, the second electron transport layer is smaller in area than an area of a region where the first electron transport layer is disposed;
forming a light emitting layer overlapping with the second electron transport layer, the light emitting layer containing an electroluminescent material; and
forming a second electrode in a region overlapping with the light emitting layer.
2 . The method of manufacturing an electroluminescence element according to claim 1 , wherein the liquid composition comprises an inorganic metal salt, a primary amide and the solvent.
3 . The method of manufacturing an electroluminescence element according to claim 1 , wherein the liquid composition is an organic Group 2 metal compound and an organic Group 3 metal compound dissolved in an organic solvent.
4 . An inverted stack electroluminescence element comprising:
A first electrode;
a second electrode having a region facing the first electrode;
a first insulating layer between the first electrode and the second electrode;
an electron transport layer electrically connected to the first electrode; and
a light emitting layer containing an electroluminescent material between the electron transport layer and the second electrode,
wherein the first insulating layer has an opening,
wherein the opening has an overlapping region where the second electrode, the light emitting layer, the electron transport layer, and the first electrode overlap,
wherein the electron transport layer has a first electron transport layer in contact with the first electrode and a second electron transport layer arranged in the opening and in contact with the first electron transport layer, and
wherein a thickness of the second electron transport layer is larger at an edge of the opening than at a center of the opening, the second electron transport layer is in contact with a side surface of the opening and rises along the side surface the second electron transport layer is positioned within the opening, an area where the second electron transport layer is arranged is smaller than an area where the first electron transport layer is arranged, and a specific resistance opening of the second electron transport layer in the range of 10 2 Ω·cm to 10 6 Ω·cm.
5 . The electroluminescence element according to claim 4 , wherein the electron mobility of the first electron transport layer is higher than the electron mobility of the second electron transport layer.
6 . The electroluminescence element according to claim 5 , wherein the carrier concentration of the first electron transport layer is higher than the carrier concentration of the second electron transport layer.
7 . The electroluminescence element according to claim 5 , wherein the first electron transport layer has a bandgap of 3.0 eV or more, and the second electron transport layer has a bandgap of 3.0 eV or more.
8 . The electroluminescence element according to claim 5 , wherein the first electron transport layer and the second electron transport layer contain an oxide semiconductor, the thickness of the second electron transport layer is larger than the thickness of the first electron transport layer, and the film thickness of the second electron transport layer is 150 nm or more.
9 . The electroluminescence element according to claim 8 ,
wherein the first electron transport layer contains tin oxide and indium oxide, and at least one selected from gallium oxide, tungsten oxide, aluminum oxide and silicon oxide,
wherein the second electron transport layer contains zinc oxide and at least one selected from silicon oxide, magnesium oxide, indium oxide, aluminum oxide and gallium oxide.
10 . The electroluminescence element according to claim 4 , wherein a work function of the second electron transport layer is 3.8 eV or less.
11 . A display device comprising:
a pixel comprising the inverted stack electroluminescence element according to claim 4 , and a driving transistor connected to the electroluminescence element on a substrate;
wherein the driving transistor comprises:
an oxide semiconductor layer,
a first insulating layer located under the oxide semiconductor layer;
a first gate electrode having a region overlapping with the oxide semiconductor layer, the first gate electrode arranged on the substrate side of the oxide semiconductor layer with the first insulating layer interposed therebetween;
a second gate electrode having a region overlapping with the oxide semiconductor layer and the first gate electrode, the second gate electrode arranged opposite to the substrate side of the oxide semiconductor layer
wherein the first electrode is electrically connected to the oxide semiconductor layer.
12 . The display device according to claim 11 , wherein the electron mobility of the first electron transport layer is higher than the electron mobility of the second electron transport layer.
13 . The display device according to claim 12 , wherein the carrier concentration of the first electron transport layer is higher than the carrier concentration of the second electron transport layer.
14 . The display device according to claim 12 , wherein the first electron transport layer has a bandgap of 3.0 eV or more, and the second electron transport layer has a bandgap of 3.0 eV or more.
15 . The display device according to claim 12 , wherein the first electron transport layer and the second electron transport layer contain an oxide semiconductor, and the thickness of the second electron transport layer is larger than the thickness of the first electron transport layer.
16 . The display device according to claim 15 ,
wherein the first electron transport layer contains tin oxide and indium oxide, and at least one selected from gallium oxide, tungsten oxide, aluminum oxide and silicon oxide,
wherein the second electron transport layer contains zinc oxide and at least one selected from silicon oxide, magnesium oxide, indium oxide, aluminum oxide and gallium oxide.
17 . The display device according to claim 11 , wherein a work function of the second electron transport layer is 3.8 eV or less.