Light-emitting device including quantum dots for enhancing luminous efficiency
A light-emitting device includes: a first electrode; a second electrode; a light-emitting layer disposed between the first electrode and the second electrode; and a hole transport layer disposed between the first electrode and the light-emitting layer, wherein the light-emitting layer includes a first quantum dot including a first core with an emission peak in a visible light region, and a second quantum dot including a second core with an emission peak in a near-ultraviolet region or an ultraviolet region.
1 . A light-emitting device comprising:
a first electrode;
a second electrode;
a light-emitting layer disposed between the first electrode and the second electrode; and
a hole transport layer disposed between the first electrode and the light-emitting layer,
wherein the light-emitting layer includes:
a first quantum dot including a first core with an emission peak in a visible light region, and
a second quantum dot including a second core with an emission peak in a near-ultraviolet region or an ultraviolet region, and
wherein:
the light-emitting layer has a layered structure comprising a first layer including the first quantum dot and a second layer including the second quantum dot,
the second layer is disposed between the first layer and the hole transport layer,
a thickness of the second layer is in a range from 10 nm to half a thickness of the first layer or less, and
near-ultraviolet light or ultraviolet light emitted by the second quantum dot is absorbed by the first quantum dot.
2 . The light-emitting device according to claim 1 ,
wherein the first quantum dot includes a first shell disposed on an outer side of the first core,
the second quantum dot includes a second shell disposed on an outer side of the second core, and
a material forming the first shell and a material forming the second shell are identical.
3 . The light-emitting device according to claim 1 ,
wherein the first quantum dot includes a first shell disposed on an outer side of the first core,
the second quantum dot includes a second shell disposed on an outer side of the second core, and
a material forming the first shell is different from a material forming the second shell.
4 . The light-emitting device according to claim 1 ,
wherein an electron affinity of the second core is less than an electron affinity of the first core.
5 . The light-emitting device according to claim 1 , further comprising:
a bank disposed in contact with a side surface of the light-emitting layer, the bank absorbing light of an emission peak of the second quantum dot.
6 . The light-emitting device according to claim 1 , further comprising:
a bank disposed in contact with a side surface of the light-emitting layer, the bank reflecting light of an emission peak of the second quantum dot.
7 . The light-emitting device according to claim 6 ,
wherein the bank includes a metal film disposed opposite the side surface of the light-emitting layer.
8 . The light-emitting device according to claim 1 ,
wherein an entirety of the second layer overlaps the first layer in a plan view of the light-emitting device.
9 . The light-emitting device according to claim 1 ,
wherein the first layer covers a side surface of the second layer.
10 . The light-emitting device according to claim 1 ,
wherein a material forming the first core and a material forming the second core are identical, and
a particle size of the first core is greater than a particle size of the second core.
11 . The light-emitting device according to claim 1 ,
wherein a material forming the first core and a material forming the second core are different.