Display devices, display modules, and electronic devices

Abstract

To provide a display device with a long lifetime.SOLUTION: A display device includes a first light-emitting device and a second light-emitting device. The first light-emitting device includes a first electrode and a common electrode. The second light-emitting device includes a second electrode and the common electrode. The first light-emitting device includes a first light-emitting layer and an electron transport layer in the order from the side of the electrode functioning as an anode among the first electrode and the common electrode. The second light-emitting device includes a second light-emitting layer between the second electrode and the common electrode. The first light-emitting layer includes a first organic compound emitting light with a first color. The second light-emitting layer includes a second organic compound emitting light with a second color. The electron transport layer includes a third organic compound and a first substance. The third organic compound is an electron transport material. The first substance is a metal, a metal salt, a metal oxide, or an organic metal salt. The electron transport layer includes a first region and a second region in which the concentration of the first substance is different.SELECTED DRAWING: Figure 1

Claims

1. Having a first light-emitting device and a second light-emitting device, The first light-emitting device has a first electrode and a common electrode, The second light-emitting device has a second electrode and the common electrode, The first light-emitting device has a first hole injection layer, a first hole transport layer, a second hole transport layer, a first light-emitting layer, and a first electron transport layer between the first electrode and the common electrode. The second light-emitting device has a second hole injection layer, a third hole transport layer, a fourth hole transport layer, and a second light-emitting layer between the second electrode and the common electrode. The second hole transport layer is in contact with the first light-emitting layer, The fourth hole transport layer is in contact with the second light-emitting layer, The first light-emitting layer has a first organic compound that emits light of a first color, The second light-emitting layer has a second organic compound that emits light of a second color, The first hole injection layer and the second hole injection layer each contain the first compound and the second compound, The HOMO level of the second compound is between -5.7 eV and -5.4 eV. The first compound has electron-accepting properties for the second compound, The first hole transport layer and the third hole transport layer each contain a third compound. The difference between the HOMO level of the third compound and the HOMO level of the second compound is within 0.2 eV. The compound contained in the second hole transport layer and the compound contained in the fourth hole transport layer are different compounds. The first electron transport layer comprises a third organic compound and a first substance, The third organic compound has a heterocyclic skeleton, The first substance is a metal, a metal salt, a metal oxide, or an organometallic salt. The first electron transport layer has a first region and a second region, A display device in which the first region and the second region have different concentrations of the first substance.

2. In claim 1, A display device wherein the HOMO level of the third compound is less than or equal to the HOMO level of the second compound.

3. In claim 1 or 2, A display device wherein the HOMO level of the fourth compound contained in the second hole transport layer is lower than the HOMO level of the third compound.

4. In any one of claims 1 to 3, A display device wherein the HOMO level of the fifth compound contained in the fourth hole transport layer is lower than the HOMO level of the third compound.

5. In any one of claims 1 to 4, A display device wherein the second compound and the third compound are the same compound.

6. In any one of claims 1 to 5, The first region is located closer to the first light-emitting layer than the second region. A display device wherein the first region has a higher concentration of the first substance compared to the second region.

7. In any one of claims 1 to 6, The second light-emitting device has a second electron transport layer, A display device wherein the second electron transport layer has the same compound as the first electron transport layer.

8. In any one of claims 1 to 7, The third organic compound is a display device having a HOMO level of -6.0 eV or higher.

9. In any one of claims 1 to 8, The second light-emitting layer comprises a fourth organic compound and a fifth organic compound, A display device in which the fourth organic compound and the fifth organic compound are a combination that forms an excited complex.

10. In any one of claims 1 to 9, The first organic compound is a fluorescent substance, and the device is a display device.

11. In any one of claims 1 to 10, The first color is blue, The second color of the aforementioned display device is red or green.

12. In any one of claims 1 to 11, A display device in which the first substance is an organometallic complex having an alkali metal or alkaline earth metal.

13. A display module comprising a display device according to any one of claims 1 to 12, and a connector or integrated circuit.

14. The display module according to claim 13, An electronic device having at least one of the following: an antenna, a battery, a housing, a camera, a speaker, a microphone, and an operating button.

Images