US-12622147-B2 - Display device, display module, electronic device, and television device

US12622147B2US 12622147 B2US12622147 B2US 12622147B2US-12622147-B2

Abstract

A display device having a long lifetime is provided. A large-sized display device is provided. A display device includes a first light-emitting device and a second light-emitting device. The first light-emitting device includes a hole-injection layer, a first light-emitting layer, and an electron-transport layer. The second light-emitting device includes a second light-emitting layer. The hole-injection layer contains a first compound and a second compound. The first light-emitting layer contains a third compound that emits light of a first color. The second light-emitting layer contains a fourth compound that emits light of a second color. The electron-transport layer contains a fifth compound. The first compound has a property of accepting electrons from the second compound. The second compound has a HOMO level higher than or equal to −5.7 eV and lower than or equal to −5.4 eV. The fifth compound has a HOMO level higher than or equal to −6.0 eV and an electron mobility higher than or equal to 1×10{circumflex over ( )}−7 cm{circumflex over ( )}2/Vs and lower than or equal to 5×10{circumflex over ( )}−5 cm{circumflex over ( )}2/Vs when the square root of electric field strength [V/cm] is 600.

Inventors

Shunpei Yamazaki
Satoshi Seo
Harue Osaka

Assignees

SEMICONDUCTOR ENERGY LABORATORY CO., LTD.

Dates

Publication Date: 20260505
Application Date: 20240624
Priority Date: 20190226

Claims (19)

1 . A display device comprising: a first light-emitting device; and a second light-emitting device, wherein the first light-emitting device comprises a first electrode and a common electrode, wherein the second light-emitting device comprises a second electrode and the common electrode, wherein the first light-emitting device comprises a hole-injection layer, a first light-emitting layer, and an electron-transport layer in this order from a side of the first electrode, wherein the second light-emitting device comprises a second light-emitting layer between the second electrode and the common electrode, wherein the hole-injection layer is in contact with the first electrode, wherein the hole-injection layer comprises a first compound and a second compound, wherein the first light-emitting layer comprises a third compound that emits light of a first color, wherein the second light-emitting layer comprises a fourth compound that emits light of a second color, wherein the electron-transport layer comprises a fifth compound, wherein the first compound comprises at least one of a cyano group and a fluoro group, wherein a HOMO level of the second compound is higher than or equal to −5.7 eV and lower than or equal to −5.4 eV, and wherein a HOMO level of the fifth compound is higher than or equal to −6.0 eV.
2 . The display device according to claim 1 , wherein the fifth compound is a triazine derivative, a phenanthroline derivative, or a compound comprising an anthracene skeleton.
3 . The display device according to claim 1 , wherein the first color is blue.
4 . The display device according to claim 1 , wherein each of the third compound and the fourth compound is a fluorescent substance.
5 . The display device according to claim 1 , wherein the second light-emitting device comprises a layer shared with the first light-emitting device between the second electrode and the common electrode.
6 . The display device according to claim 1 , wherein the second compound comprises at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
7 . The display device according to claim 1 , wherein the electron-transport layer further comprises an organic complex comprising an alkali metal or an alkaline earth metal.
8 . A display device comprising: a first light-emitting device; and a second light-emitting device, wherein the first light-emitting device comprises a first electrode and a common electrode, wherein the second light-emitting device comprises a second electrode and the common electrode, wherein the first light-emitting device comprises a hole-injection layer, a first hole-transport layer, a first light-emitting layer, and an electron-transport layer in this order from a side of the first electrode, wherein the second light-emitting device comprises a second light-emitting layer between the second electrode and the common electrode, wherein the hole-injection layer is in contact with the first electrode, wherein the hole-injection layer comprises a first compound and a second compound, wherein the first light-emitting layer comprises a third compound that emits light of a first color, wherein the second light-emitting layer comprises a fourth compound that emits light of a second color, wherein the electron-transport layer comprises a fifth compound, wherein the first hole-transport layer comprises a sixth compound, wherein the first compound comprises at least one of a cyano group and a fluoro group, wherein a HOMO level of the second compound is higher than or equal to −5.7 eV and lower than or equal to −5.4 eV, wherein a HOMO level of the fifth compound is higher than or equal to −6.0 eV, wherein a HOMO level of the sixth compound is lower than or equal to the HOMO level of the second compound, and wherein a difference between the HOMO level of the sixth compound and the HOMO level of the second compound is 0.2 eV or less.
9 . The display device according to claim 8 , wherein the fifth compound is a triazine derivative, a phenanthroline derivative, or a compound comprising an anthracene skeleton.
10 . The display device according to claim 8 , wherein the first color is blue.
11 . The display device according to claim 8 , wherein each of the third compound and the fourth compound is a fluorescent substance.
12 . The display device according to claim 8 , wherein the second light-emitting device comprises a layer shared with the first light-emitting device between the second electrode and the common electrode.
13 . The display device according to claim 8 , wherein the second compound comprises at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
14 . The display device according to claim 8 , wherein the electron-transport layer further comprises an organic complex comprising an alkali metal or an alkaline earth metal.
15 . The display device according to claim 8 , wherein the first light-emitting device further comprises a second hole-transport layer, wherein the second hole-transport layer comprises a seventh compound, and wherein a HOMO level of the seventh compound is lower than the HOMO level of the sixth compound.
16 . A display device comprising: a first light-emitting device; a second light-emitting device; and a third light-emitting device, wherein the first light-emitting device comprises a first electrode and a common electrode, wherein the second light-emitting device comprises a second electrode and the common electrode, wherein the third light-emitting device comprises a third electrode and the common electrode, wherein the first light-emitting device comprises a hole-injection layer, a first light-emitting layer, and an electron-transport layer in this order from a side of the first electrode, wherein the second light-emitting device comprises a second light-emitting layer between the second electrode and the common electrode, wherein the third light-emitting device comprises a third light-emitting layer between the third electrode and the common electrode, wherein the hole-injection layer is in contact with the first electrode, wherein the hole-injection layer comprises a first compound and a second compound, wherein the electron-transport layer comprises a third compound, wherein the first compound comprises at least one of a cyano group and a fluoro group, wherein a HOMO level of the second compound is higher than or equal to −5.7 eV and lower than or equal to −5.4 eV, wherein a maximum peak wavelength of an emission spectrum of the first light-emitting device is shorter than a maximum peak wavelength of an emission spectrum of the second light-emitting device, wherein the maximum peak wavelength of the emission spectrum of the second light-emitting device is shorter than a maximum peak wavelength of an emission spectrum of the third light-emitting device, and wherein in a top view, an area of a light-emitting region of the first light-emitting device is larger than or equal to an area of a light-emitting region of the third light-emitting device and smaller than or equal to an area of a light-emitting region of the second light-emitting device.
17 . The display device according to claim 16 , wherein the third compound is a triazine derivative, a phenanthroline derivative, or a compound comprising an anthracene skeleton.
18 . The display device according to claim 16 , wherein the second compound comprises at least one of a carbazole skeleton, a dibenzofuran skeleton, a dibenzothiophene skeleton, and an anthracene skeleton.
19 . The display device according to claim 16 , wherein the electron-transport layer further comprises an organic complex comprising an alkali metal or an alkaline earth metal.

Description

CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation of U.S. application Ser. No. 17/431,246, filed Aug. 16, 2021, now allowed, which is incorporated by reference and is a U.S. National Phase Application under 35 U.S.C. § 371 of International Application PCT/IB2020/051228, filed on Feb. 14, 2020, which is incorporated by reference and claims the benefit of foreign priority applications filed in Japan on Feb. 26, 2019, as Application No. 2019-033191, on Apr. 19, 2019, as Application No. 2019-080050, and on Jul. 2, 2019, as Application No. 2019-123874. TECHNICAL FIELD One embodiment of the present invention relates to a display device, a display module, an electronic device, and a television device. Note that one embodiment of the present invention is not limited to the above technical field. Examples of the technical field of one embodiment of the present invention include a semiconductor device, a display device, a light-emitting apparatus, a power storage device, a memory device, an electronic device, a lighting device, an input device (e.g., a touch sensor), an input/output device (e.g., a touch panel), a driving method thereof, and a manufacturing method thereof. BACKGROUND ART In recent years, application of display devices to a variety of uses has been expected. Examples of uses for a large display device include a television device for home use (also referred to as a TV or a television receiver), digital signage, and a PID (Public Information Display). In addition, a smartphone and a tablet terminal including a touch panel are being developed as portable information terminals. Light-emitting apparatuses including light-emitting devices (also referred to as light-emitting elements) have been developed as display devices, for example. Light-emitting devices (also referred to as EL devices or EL elements) utilizing an electroluminescence (hereinafter referred to as EL) phenomenon have features such as ease of reduction in thickness and weight, high-speed response to an input signal, and driving with a direct-current low voltage source, and application of the light-emitting devices to display devices has been discussed. For example, Patent Document 1 discloses a flexible light-emitting apparatus including an organic EL device (also referred to as an organic EL element). REFERENCE Patent Document [Patent Document 1] Japanese Published Patent Application No. 2014-197522 SUMMARY OF THE INVENTION Problems to be Solved by the Invention An object of one embodiment of the present invention is to provide a long-lifetime display device. An object of one embodiment of the present invention is to provide a highly reliable display device. An object of one embodiment of the present invention is to provide a large-sized display device. An object of one embodiment of the present invention is to provide a display device with high resolution. An object of one embodiment of the present invention is to provide a display device with high productivity. An object of one embodiment of the present invention is to provide a display device with high display quality. Note that the description of these objects does not preclude the existence of other objects. One embodiment of the present invention does not need to achieve all the objects. Other objects can be derived from the description of the specification, the drawings, and the claims. Means for Solving the Problems One embodiment of the present invention is a display device including 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 hole-injection layer, a first light-emitting layer, and an electron-transport layer in this order from a side of one of the first electrode and the common electrode that functions as an anode. The second light-emitting device includes a second light-emitting layer between the second electrode and the common electrode. The hole-injection layer is in contact with the one of the first electrode and the common electrode that functions as the anode. The hole-injection layer contains a first compound and a second compound. The first light-emitting layer contains a third compound that emits light of a first color. The second light-emitting layer contains a fourth compound that emits light of a second color. The electron-transport layer contains a fifth compound. The first compound has a property of accepting an electron from the second compound. The second compound has a HOMO level higher than or equal to −5.7 eV and lower than or equal to −5.4 eV. The fifth compound has a HOMO level higher than or equal to −6.0 eV and an electron mobility higher than or equal to 1×10−7 cm2/Vs and lower than or equal to 5×10−5 cm2/Vs when the square root of electric field strength [V/cm] is 600. The second light-emitting devic