Abstract: A QD is a Cd-free quantum dot including a core and a shell and configured to emit blue light. The core at least contains Zn and Se. The shell has a film thickness in a range from 0.5 nm to 3 nm, contains Zn, Se, and S in a boundary portion adjacent to the core, and contains Zn and S in an outermost portion.

Abstract: A quantum dot includes a core including Zn and Se, and a shell composed of ZnS and provided on a surface of the core, adjacently to the core. The quantum dot-emits blue light, is Cd free, and has a particle diameter within a range from 3 nm to 20 nm and a fluorescence lifetime in a thin film state of 50 ns or less.

Abstract: A light-emitting element includes an anode electrode, a QD layer containing QDs, and a cathode electrode, in which the QDs have a core-shell structure including a core and a shell and are Cd-free QDs that emit blue light, the QDs contain halogen elements, and an external quantum efficiency percentage of the light-emitting element is 7% or more.

Abstract: An object is to provide a quantum dot that has a narrow fluorescence half-width and a high fluorescence quantum yield, and emits blue fluorescence. A quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a particle diameter of 5 nm or more and 20 nm or less. In addition, the quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a fluorescence quantum yield of 58 or more and a fluorescence half-width of 25 nm or less. In the present invention, the fluorescence lifetime can be made 50 ns or less.

Abstract: An object of the present invention is to provide a quantum dot and a method for manufacturing a quantum dot capable of enhancing the EQE. A method for manufacturing the quantum dot of the present invention includes steps of: generating a core and coating a shell on a surface of the core, wherein in the step of coating the shell, an acidic compound and a zinc halide compound are blended in a shell raw material. In the present invention, the step of coating the shell is divided into at least a first half and a second half. In the first half, a shell raw material in which the acidic compound is blended and the zinc halide compound is not blended is used, while in the second half, it is preferable that the shell is coated a plurality of times using the shell raw material in which both the acidic compound and the zinc halide compound are blended.

Abstract: An object is to provide a quantum dot that has a narrow fluorescence half-width and a high fluorescence quantum yield, and emits blue fluorescence. A quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a particle diameter of 5 nm or more and 20 nm or less. In addition, the quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a fluorescence quantum yield of 5% or more and a fluorescence half-width of 25 nm or less. In the present invention, the fluorescence lifetime can be made 50 ns or less.

Abstract: An object of the present invention is to provide a method for manufacturing quantum dots capable of containing a large amount of Zn on a surface thereof, and a quantum dot. A method for manufacturing quantum dots of the present invention includes a step of producing a core containing at least Ag, Ga, and S or Ag, Ga, and Se, and a step of coating a surface of the core with a shell, and in the step of coating with the shell, the surface of the core is coated with GaS, and then Zn is added. It is preferable that the surface of the core is coated with ZnS after being coated with GaS. It is preferable that the core and the shell do not contain Cd and In.

Abstract: A quantum dot (QD) dispersion solution includes QD phosphor particles, ligands, and a solvent. Each ligand includes a thiol group and at least one functional group of ester groups and ether groups. The solvent is propylene glycol monomethyl ether acetate.

Abstract: An object is to provide a quantum dot that has a narrow fluorescence half-width and a high fluorescence quantum yield, and emits blue fluorescence. A quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a particle diameter of 5 nm or more and 20 nm or less. In addition, the quantum dot (5) according to the present invention includes at least Zn and Se and does not include Cd, and has a fluorescence quantum yield of 5% or more and a fluorescence half-width of 25 nm or less. In the present invention, the fluorescence lifetime can be made 50 ns or less.