US-12628495-B2 - Light emitting device and display device including the same

US12628495B2US 12628495 B2US12628495 B2US 12628495B2US-12628495-B2

Abstract

An electroluminescent device includes a quantum dot layer disposed between a first electrode and a second electrode, and an electron transport layer disposed between the quantum dot layer and the second electrode; wherein the quantum dot layer is configured to emit a first light, the quantum dot layer including first quantum dots, wherein the first quantum dots include a first semiconductor nanocrystal, wherein the electron transport layer includes zinc oxide nanoparticles, wherein the electroluminescent device further comprises a first layer between the quantum dot layer and the electron transport layer, the first layer including inorganic nanoparticles, wherein the inorganic nanoparticles has a different composition from the zinc oxide nanoparticles and the first quantum dots, and wherein the inorganic nanoparticles comprises a metal chalcogenide having a bandgap energy of greater than or equal to about 2.9 electron volts (eV) and less than or equal to about 10 eV.

Inventors

Oul CHO
KWANGHEE KIM
Yuho WON
Jae Yong Lee
Taehyung Kim

Assignees

SAMSUNG ELECTRONICS CO., LTD.

Dates

Publication Date: 20260512
Application Date: 20230831
Priority Date: 20220831

Claims (20)

1 . An electroluminescent device comprising a first electrode; a second electrode; a quantum dot layer disposed between the first electrode and the second electrode; and an electron transport layer disposed between the quantum dot layer and the second electrode; wherein the quantum dot layer is configured to emit a first light, the quantum dot layer comprising a plurality of first quantum dots, wherein the first quantum dots comprise a first semiconductor nanocrystal, wherein the electron transport layer comprises zinc oxide nanoparticles, wherein the electroluminescent device further comprises a first layer between the quantum dot layer and the electron transport layer, the first layer comprising a plurality of inorganic nanoparticles, wherein the inorganic nanoparticle has a different composition from the zinc oxide nanoparticle and the first quantum dot, and wherein the plurality of inorganic nanoparticles comprises a metal chalcogenide, and the metal chalcogenide has a bandgap energy that is greater than an optical energy of the first light.
2 . The electroluminescent device of claim 1 , wherein the first quantum dot comprises a Group II-VI compound, a Group III-V compound, a Group IV-VI compound, a Group IV element or a compound thereof, a Group compound, a Group I-II-IV-VI compound, or a combination thereof, wherein the first light has a red light spectrum, a green light spectrum, or a blue light spectrum, and optionally wherein a full width at half maximum of the first light is greater than or equal to about 1 nanometer and less than or equal to about 55 nanometers.
3 . The electroluminescent device of claim 1 , wherein the first quantum dot comprises a core comprising the first semiconductor nanocrystal and a shell disposed on the core, and the first semiconductor nanocrystal comprises a zinc chalcogenide, an indium phosphide, or a combination thereof.
4 . The electroluminescent device of claim 1 , wherein the quantum dot layer does not comprise the inorganic nanoparticle.
5 . The electroluminescent device of claim 1 , wherein the zinc oxide nanoparticle further comprises an alkali metal, an alkali earth metal, Zr, W, Li, Ti, Y, Al, gallium, indium, tin, cobalt, vanadium, or a combination thereof.
6 . The electroluminescent device of claim 1 , wherein the metal chalcogenide comprises zinc, magnesium, calcium, barium, or a combination thereof; or wherein the bandgap energy of the metal chalcogenide is greater than or equal to about 2.9 electron volts and less than or equal to about 10 electron volts.
7 . The electroluminescent device of claim 1 , wherein the metal chalcogenide comprises a magnesium sulfide, a magnesium selenide, a magnesium sulfide selenide, a zinc magnesium selenide, a zinc magnesium sulfide, a zinc sulfide, a zinc selenide sulfide, or a combination thereof.
8 . The electroluminescent device of claim 1 , wherein the inorganic nanoparticle has a size of greater than or equal to about 2 nanometers and less than or equal to about 30 nanometers, and optionally wherein the bandgap energy of the metal chalcogenide is greater than or equal to about 3.2 electron volts and less than or equal to about 6.8 electron volts.
9 . The electroluminescent device of claim 1 , wherein the first layer further comprises a plurality of second quantum dots, and optionally wherein the second quantum dot comprises the first semiconductor nanocrystal.
10 . The electroluminescent device of claim 9 , wherein the second quantum dot comprises a core comprising the first semiconductor nanocrystal and a shell disposed on the core, and the first semiconductor nanocrystal comprises a zinc chalcogenide, an indium phosphide, or a combination thereof.
11 . The electroluminescent device of claim 9 , wherein as the first layer is exposed to a high-power laser emitting light of a predetermined wavelength for 60 seconds, the first layer has a luminance intensity maintenance percentage of greater than or equal to about 100% and less than or equal to about 120% based on an initial luminance intensity of 100%.
12 . The electroluminescent device of claim 1 , wherein a thickness of the first layer is greater than or equal to about 4 nanometers and less than or equal to about 50 nanometers, and optionally wherein the quantum dot layer has a thickness of greater than or equal to about 5 nanometers and less than or equal to about 50 nanometers.
13 . The electroluminescent device of claim 1 , wherein the electroluminescent device is configured to emit blue light; and wherein the electroluminescent device exhibits a maximum luminance of greater than or equal to about 100,000 candelas per square meter, or wherein the electroluminescent device exhibits a maximum external quantum efficiency of greater than or equal to about 11%, or wherein the electroluminescent device exhibits a T90 of greater than or equal to about 26 hours as measured at an initial luminance of 650 candelas per square meter.
14 . A display device comprising the electroluminescent device of claim 1 .
15 . The display device of claim 14 , wherein the display device comprises a handheld terminal, a monitor, a notebook computer, a television, an electronic display board, a camera, or an electronic component for an autonomous vehicle.
16 . An electroluminescent device comprising a first electrode; a second electrode; a light emitting layer disposed between the first electrode and the second electrode, the light emitting layer comprising a semiconductor nanoparticle population; and optionally, an electron auxiliary layer between the light emitting layer and the second electrode, wherein the light emitting layer is configured to emit a first light, wherein the semiconductor nanoparticle population comprises a plurality of quantum dots and a plurality of inorganic nanoparticles, wherein the first light has a full width at half maximum of greater than or equal to about 1 nanometer and less than or equal to about 55 nanometers, wherein the semiconductor nanoparticle population exhibits a multi-modal distribution comprising a first peak particle size and a second peak particle size in a size analysis, wherein the second peak particle size is greater than the first peak particle size, and wherein the first peak particle size is greater than or equal to about 2 nanometers and less than or equal to about 15 nanometers.
17 . The electroluminescent device of claim 16 , wherein the quantum dots comprise a first semiconductor nanocrystal, and the inorganic nanoparticle comprises a metal chalcogenide, and a bandgap energy of the inorganic nanoparticle is greater than a bandgap energy of the first semiconductor nanocrystal by greater than or equal to about 0.1 electron volts.
18 . The electroluminescent device of claim 16 , wherein the quantum dot comprises a zinc chalcogenide comprising zinc and selenium, the inorganic nanoparticle comprises a metal sulfide, and the metal sulfide comprises zinc, magnesium, or a combination thereof.
19 . The electroluminescent device of claim 16 , wherein the first peak particle size is greater than or equal to about 3 nanometers and less than or equal to about 10 nanometers.
20 . The electroluminescent device of claim 16 , wherein the second peak particle size is greater than or equal to about 5 nanometers and less than or equal to about 50 nanometers, and optionally wherein a difference between the first peak particle size and the second peak particle size is greater than or equal to about 4 nanometers and less than or equal to about 20 nanometers.

Description

CROSS-REFERENCE TO RELATED APPLICATION This application claims priority to Korean Patent Application No. 10-2022-0109987 filed in the Korean Intellectual Property Office on Aug. 31, 2022, and all the benefits accruing therefrom under 35 U.S.C. § 119, the content of which in its entirety is herein incorporated by reference. BACKGROUND 1. Field The present disclosure relates to a light emitting (e.g., electroluminescent) device and a display device including the electroluminescent device. 2. Description of the Related Art A semiconductor nanoparticle (e.g., a semiconductor nanocrystal particle) having a nanometer size may exhibit luminescence properties. For example, a quantum dot including a semiconductor nanocrystal may exhibit a quantum confinement effect. The light emission from the semiconductor nanoparticle may occur when an electron in an excited state resulting from light excitation or an applied voltage transitions from a conduction band to a valence band. The semiconductor nanoparticle may be configured to emit light of a desired wavelength region by adjusting a size of the semiconductor nanoparticle, a composition of the semiconductor nanoparticle, or a combination thereof. A semiconductor nanoparticle may be used, for example, in a light emitting device (e.g., an electroluminescent device) or a display device including the electroluminescent device. SUMMARY An embodiment provides a luminescent device that is configured to emit light, for example, by applying a voltage to a nanostructure (e.g., a semiconductor nanoparticle such as a quantum dot), for example with or without a separate irradiation light source. An embodiment provides a display device (e.g., a quantum dot-light emitting diode (“QD-LED”) display device) that includes a semiconductor nanoparticle such as a quantum dot as a component of a light emitting layer in a pixel configuration (e.g., in a configuration of a blue pixel, a red pixel, a green pixel, or a combination thereof). An embodiment provides a method of producing the electroluminescent device. In an embodiment, an electroluminescent device includes: a first electrode and a second electrode spaced apart from each other (e.g., each electrode having a surface opposite the other), a quantum dot layer disposed between the first electrode and the second electrode, and an electron transport layer disposed between the quantum dot layer and the second electrode;wherein the quantum dot layer is configured to emit a first light, the quantum dot layer including a plurality of first quantum dots,wherein the first quantum dot includes a first semiconductor nanocrystal,wherein the electron transport layer includes zinc oxide nanoparticles,wherein the electroluminescent device further includes a first layer between the quantum dot layer and the electron transport layer, the first layer including a plurality of inorganic nanoparticles,wherein the inorganic nanoparticle has a different composition from the zinc oxide nanoparticle and the first quantum dot (for example, the first semiconductor nanocrystal), andwherein the inorganic nanoparticle includes a metal chalcogenide, and wherein the metal chalcogenide has a bandgap energy that is greater than an optical energy of the first light. The bandgap energy of the metal chalcogenide may be greater than or equal to about 2.9 eV, greater than or equal to about 3.2 eV, greater than or equal to about 3.4 eV, and less than or equal to about 10 eV. The first light may have a red light spectrum, a green light spectrum, or a blue light spectrum. A full width at half maximum of the first light may be less than or equal to about 55 nanometers (nm), less than or equal to about 46 nm, or less than or equal to about 45 nm. The first light (or a luminescent peak thereof) may have a full width at half maximum of greater than or equal to about 1 nm, or greater than or equal to about 10 nm. As an applied voltage on the electroluminescent device is changed from about 2 volts to about 6 volts, a luminescent peak of the first light may exhibit a blue shift of greater than or equal to about 8 nm and less than or equal to about 15 nm. As an applied voltage on the electroluminescent device is changed from about 2 volts to about 6 volts, a full width at half maximum of the first light may decrease by greater than or equal to about 8 nm and less than or equal to about 20 nm. The first quantum dots may have a core-shell structure. The core shell structure may include a core including the first semiconductor nanocrystal and a shell disposed on the core. The shell may include a crystalline or amorphous inorganic material. The first semiconductor nanocrystal may include a zinc chalcogenide (e.g., a zinc selenide, a zinc selenide telluride), indium phosphide, or a combination thereof. The quantum dot layer may not include the plurality of inorganic nanoparticles. The zinc oxide nanoparticles may further include an alkali metal, an alkaline earth metal, Zr, W, Li, Ti, Y, Al,