Light-emitting element, light-emitting device, and method of manufacturing light- emitting element
A light-emitting element includes: an anode; a cathode; and a light-emitting layer between the anode and the cathode, wherein the light-emitting layer contains quantum dots and ligands, the ligands are a polymer including at least two repeating units, and each repeating unit includes, at an end of at least one side chain thereof, a modified functional group coordinated to any one of the quantum dots.
1 . A light-emitting element comprising:
an anode;
a cathode; and
a light-emitting layer between the anode and the cathode, wherein:
the light-emitting layer contains quantum dots and ligands,
each of the ligands comprises a polymer including at least two repeating units,
each of the at least two repeating units includes, at an end of at least one side chain thereof, a modified functional group coordinated with any one of the quantum dots, and
each of the at least two repeating units has a formula (3):
where n and m are natural numbers, X is the modified functional group, and each R1 is independently selected from a hydrogen atom, an alkyl group, an aryl group, and an alkoxy group.
2 . The light-emitting element according to claim 1 , wherein m is from 1 to 5, both inclusive.
3 . The light-emitting element according to claim 1 , wherein m is from 5 to 20, both inclusive.
4 . The light-emitting element according to claim 1 , wherein each ligand includes a polymerizable functional group.
5 . The light-emitting element according to claim 1 , wherein the modified functional group includes at least one of a thiol group, a hydroxyl group, a carboxy group, and an amino group.
6 . The light-emitting element according to claim 1 , further comprising:
a hole transport layer between the anode and the light-emitting layer; and
an electron transport layer between the cathode and the light-emitting layer.
7 . A light-emitting device comprising the light-emitting element according to claim 1 .
8 . A method of manufacturing the light-emitting element according to claim 1 , the method comprising:
simultaneously heating, and shining ultraviolet light on, a first solution containing the quantum dots and first ligands, each first ligand including a polymerizable functional group including, at an end of at least one side chain of the polymerizable functional group, a first modified functional group coordinated to any one of the quantum dots, to form the light-emitting layer containing the quantum dots and the first ligands in which at least some of the polymerizable functional groups are polymerized with each other.
9 . The method according to claim 8 , wherein each first ligand includes 6-acrylamide hexanoic acid or 2-aminoethyl methacrylamide before simultaneously heating, and shining the ultraviolet light on, the first solution.
10 . The method according to claim 8 , wherein the first modified functional group includes at least one of a thiol group, a hydroxyl group, a carboxy group, and an amino group.
11 . The method according to claim 8 , further comprising, before simultaneously heating, and shining the ultraviolet light on, the first solution:
stirring the first solution and a second solution to replace second ligands, that coordinated to the quantum dots, with the first ligands, the second solution containing the quantum dots and the second ligands, each second ligand including no polymerizable functional group, but including a second modified functional group coordinated to at least one of the quantum dots.
12 . The method according to claim 11 , wherein the first solution contains an aqueous medium, and the second solution contains an organic medium.
13 . The method according to claim 11 , wherein the first solution contains a non-aqueous medium, and the second solution contains an aqueous medium.