Semiconductor Nanoparticle Heat Treatment for Band-Edge Emission Purity

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Solution Overview

Problem

Existing methods for producing semiconductor nanoparticles with band-edge emission purity are inefficient and require improvement.

Innovation Solution

A method involving a first heat treatment of a mixture containing silver (Ag) salt, indium (In) salt, a gallium-sulfur (Ga—S) bond compound, gallium halide, and an organic solvent to produce semiconductor nanoparticles, followed by a second heat treatment with gallium halide to enhance band-edge emission purity and internal quantum yield.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If one-pot synthesis is used to produce semiconductor nanoparticles, then production efficiency is improved, but band-edge emission purity is insufficient

Engineering Contradiction:

Improveproduction efficiencyVSAvoidband-edge emission purity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The synthesis process is divided into two distinct heat treatment steps: a first heat treatment to form the core semiconductor nanoparticles, and a second heat treatment to form the shell structure. This segmentation allows each step to be optimized independently, achieving both high production efficiency and high band-edge emission purity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention creates a core-shell structure where the core and shell have different compositions and properties. The core contains Ag, In, Ga, and S, while the shell contains Ga and S with higher Ga content. This local differentiation of material composition allows the core to provide efficient light emission while the shell improves emission purity and stability.

Inventive Principle:

Principle #3Local quality

2Device complexity

If existing synthesis methods are used, then production process is simple, but internal quantum yield is insufficient

Engineering Contradiction:

Improveproduction process complexityVSAvoidinternal quantum yield

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The invention utilizes different heat treatment conditions (temperature, time, atmosphere) to control the formation of core and shell structures. By changing these parameters between the two heat treatment steps, the process achieves high internal quantum yield while maintaining reasonable process complexity.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention produces composite semiconductor nanoparticles with a core-shell structure containing different materials (Ag-In-Ga-S core and Ga-S shell). This composite structure enhances the internal quantum yield by combining the advantages of different semiconductor materials while maintaining a manageable production process.

Inventive Principle:

Principle #40Composite materials

3Loss of time

If semiconductor nanoparticles are produced without optimized heat treatment, then production time is short, but emission characteristics are insufficient

Engineering Contradiction:

Improveproduction timeVSAvoidemission characteristics

Core Design Contradiction:

Loss of timeVSManufacturing precision

Solution Approach 1:

The invention employs continuous heat treatment processes where the first heat treatment is followed directly by the second heat treatment without interruption. This continuous processing maintains optimal conditions throughout, achieving high emission characteristics while minimizing total production time.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The first heat treatment performs preliminary formation of the core structure before the second heat treatment adds the shell. This preliminary action allows the core to form efficiently first, then the shell is added in a subsequent step, optimizing both time and emission characteristics.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The method efficiently produces semiconductor nanoparticles with band-edge emission purity of 70% or higher and internal quantum yield of 15% or more, utilizing a core-shell structure with improved emission characteristics.

Implementation Method 1

performing a first heat treatment of a first mixture comprising a silver (Ag) salt, an indium (In) salt, a compound having a gallium-sulfur (Ga—S) bond, a first gallium halide, and an organic solvent, to obtain first semiconductor nanoparticles

Methodology Applied

Scientific EffectHeat treatment: Heat Treatment

Implementation Method 2

The semiconductor nanoparticles exhibit band-edge emission with an emission peak wavelength in a wavelength range of 475 nm to 560 nm when irradiated with a light having a wavelength of 365 nm

Methodology Applied

Scientific EffectPhotoluminescence: Photoluminescence

Data Source

PatentUS20250320407A1Method for producing semiconductor nanoparticles, semiconductor nanoparticles, and light-emitting device

Publication Date: 2025.10.16 NICHIA CORP

AI summary

Provided is a method of efficiently producing semiconductor nanoparticles that exhibit band-edge emission with a high band-edge emission purity. The method comprises performing a first heat treatment of a first mixture comprising a silver (Ag) salt, an indium (In) salt, a compound having a gallium-sulfur (Ga—S) bond, a first gallium halide, and an organic solvent, to obtain first semiconductor nanoparticles.