Perovskite Nanoparticle Purification for Stable α-Phase Quantum Dots

Solution Overview

Problem

Existing methods for synthesizing quantum dots with a perovskite-type crystal structure require high temperatures and result in unstable α-phase crystalline phases that change over time, limiting industrial application and performance.

Innovation Solution

A method involving the use of a ligand solution with a low dielectric constant and associative ligands having a main chain with polar groups to selectively increase the ratio of the α-phase in multiple crystal structures, stabilizing the nanoparticle dispersion and maintaining the α-phase over time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a high temperature condition of 260°C is used to synthesize quantum dots, then the α-phase can be obtained, but the synthesis method is suppressed from industrial application and the crystalline phase changes gradually from the α-phase to another with time

Engineering Contradiction:

Improvecrystalline phase stabilityVSAvoidsynthesis temperature

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The patent changes the temperature parameter from high (260°C) to low (room temperature or mild heating conditions) while introducing ligand exchange as a new parameter to achieve the same α-phase stabilization effect, making the process industrially viable

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent introduces ligands (such as oleic acid, oleylamine, or their derivatives) as intermediary substances that mediate between the nanoparticle surface and the crystal structure, enabling α-phase stabilization without requiring high temperature conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If a high temperature condition of 260°C is used to synthesize quantum dots, then the α-phase can be obtained, but the method has limited industrial application

Engineering Contradiction:

Improvecrystalline phase stabilityVSAvoidindustrial applicability

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent changes the temperature parameter from high (260°C) to low (room temperature or mild heating conditions) while introducing ligand exchange as a new parameter to achieve the same α-phase stabilization effect, making the process industrially viable

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conventional synthesis methods are used, then quantum dots can be produced, but the α-phase is difficult to selectively produce and the crystalline phase is unstable over time

Engineering Contradiction:

Improvecrystalline phase stabilityVSAvoidcrystalline phase selectivity

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent introduces ligands (such as oleic acid, oleylamine, or their derivatives) as intermediary substances that mediate between the nanoparticle surface and the crystal structure, enabling α-phase stabilization without requiring high temperature conditions

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent performs ligand exchange treatment after nanoparticle synthesis to preliminarily stabilize the crystal structure, preventing subsequent phase transitions and ensuring long-term α-phase retention

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 enables the production of quantum dots with a stable α-phase at lower temperatures, ensuring consistent performance and stability of the crystalline phase.

Implementation Method 1

an associative ligand that includes a main chain having a plurality of carbon atoms and a polar group having a higher polarity than the main chain and self-associating in the solvent

Methodology Applied

Scientific EffectSelf-association: Self-Assembly

Implementation Method 2

the step of preparing the nanoparticle dispersion includes a step of selectively increasing the ratio of the content of a prescribed crystal structure in the multiple crystal structures

Methodology Applied

Scientific EffectPhase transition: Phase Change

Data Source

PatentUS20260071075A1Purification method of nanoparticle, nanoparticle composition, and manufacturing method of nanoparticle composition

Publication Date: 2026.03.12 CANON KK

AI summary

A method includes a step of preparing a nanoparticle that has a perovskite-type crystal structure as an allotrope and includes multiple crystal structures, a step of preparing a ligand solution containing a solvent that has a relative dielectric constant of a prescribed value or less and an associative ligand that includes a main chain having a plurality of carbon atoms and a polar group having a higher polarity than the main chain and self-associates in the solvent, and a step of preparing a nanoparticle dispersion by bringing the nanoparticle and the ligand solution into contact with each other, wherein the step of preparing a nanoparticle dispersion includes a step of selectively increasing the ratio of the content of a prescribed crystal structure in the multiple crystal structures.