Nanoparticle Material and Light-Emitting Device

Patent metadata

Field	Value
Publication number	US-2016233449-A1
Application number	US-201615099796-A
Country	US
Kind code	A1
Filing date	Apr 15, 2016
Priority date	Oct 17, 2013
Publication date	Aug 11, 2016
Grant date	—

Abstract

A light-emitting device having a first light-emitting layer with a first quantum dot having a first core part and a first shell part. The first shell part has a surface coated with a surfactant, and the first shell part has a thickness of 3 to 5 ML based on the constituent molecule of the first shell part. The light-emitting device also can have second light-emitting layer with a second quantum dot having a second core part and a second shell part. The second shell part has a surface coated with two types of hole-transporting and electron-transporting surfactants, and the second shell part has a thickness of less than 3 ML based on the constituent molecule of the second shell part.

First claim

1 . A nanoparticle material comprising:
a core part; and a shell part coating the core part, wherein the shell part has a surface coated with a surfactant, and the shell part has a thickness of 3 to 5 monolayers based on a constituent molecule of the shell part.

2 . The nanoparticle material according to claim 1 , wherein the surfactant comprises a first surfactant that has a hole transport property and a second surfactant that has an electron transport property.

3 . The nanoparticle material according to claim 2 , wherein the surface of the shell part is coated with both of the first and second surfactants.

4 . The nanoparticle material according to claim 3 , wherein the first surfactant has a first valence band that achieves a tunneling resonance with a second valence band of the core part and an excitation level of the second valence band.

5 . The nanoparticle material according to claim 2 , wherein the first surfactant has a first valence band that achieves a tunneling resonance with a second valence band of the core part and an excitation level of the second valence band.

6 . The nanoparticle material according to claim 2 , wherein the second surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the core part and an excitation level of the conduction band of the core part.

7 . The nanoparticle material according to claim 3 , wherein the second surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the core part and an excitation level of the conduction band of the core part.

8 . The nanoparticle material according to claim 4 , wherein the second surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the core part and an excitation level of the conduction band of the core part.

9 . The nanoparticle material according to claim 5 , wherein the second surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the core part and an excitation level of the conduction band of the core part.

10 . The nanoparticle material according to claim 1 , wherein the surfactant has an electron transport property.

11 . The nanoparticle material according to claim 10 , wherein the surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the core part and an excitation level of the conduction band of the core part.

12 . The nanoparticle material according to claim 1 , wherein the surfactant has an insulating property.

13 . The nanoparticle material according to claim 1 , wherein the shell part has an energy level of a valence band based on a vacuum level that is lower than an energy level of a valence band of the core part based on a vacuum level.

14 . A light-emitting device comprising:
a hole transport layer; an electron transport layer; and a light-emitting layer interposed between the hole transport layer and the electron transport layer, the light-emitting layer emitting light when an electric current is injected into the light-emitting layer, wherein the light-emitting layer has a stacked structure including: a first light-emitting layer composed of a first quantum dot having a first core part, and a first shell part coating the first core part, the first shell part having a first surface coated with a first surfactant that has a hole transport property and a second surfactant that has an electron transport property, the first shell part having a thickness of 3 to 5 monolayers based on a constituent molecule of the first shell part; and a second light-emitting layer composed of a second quantum dot having a second core part, and a second shell part, the second shell part having a thickness of less than 3 monolayers based on a constituent molecule of the second shell part, and the second shell part having a second surface coated with both the first surfactant having a hole transport property and the second surfactant having an electron transport property, and the first light-emitting layer is disposed proximal to the electron transport layer relative to the second light-emitting layer, and the second light-emitting layer is disposed proximal to the hole transport layer relative to the first light-emitting layer.

15 . The light-emitting device according to claim 14 , wherein the first light-emitting layer has a thickness of 0.5 to 2 monolayers based on a particle size of the first quantum dot.

16 . The light-emitting device according to claim 14 , wherein each of the first and second shell parts has an energy level of a valence band based on a vacuum level that is lower than an energy level of a valence band of the electron transport layer or an HOMO level of the electron transport layer.

17 . The light-emitting device according to claim 14 , wherein the second surfactant has a conduction band that achieves a tunneling resonance with a conduction band of the first core part and an excitation level of the valence band of the first core part.

Assignees

• Murata Manufacturing Co

Inventors

• Murayama Koji
• Miyata Haruya

Classifications

• H10K50/115

  comprising active inorganic nanostructures, e.g. luminescent quantum dots · CPC title

• C09K11/025 Primary

  non-luminescent particle coatings or suspension media · CPC title

• H01L51/502 Primary

  Electricity · mapped topic

• H01L51/0003

  Electricity · mapped topic

• H01L51/504

  Electricity · mapped topic