Ligand-Coordinated Inorganic Nanoparticle Carrier Transport Layer
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Solution Overview
Problem
The carrier transport layer in light-emitting elements using inorganic nanoparticles faces issues with dispersibility and agglomeration when particle size is reduced, leading to deterioration or dissolution in solvents of different polarities, resulting in low liquid resistance and reliability.
Innovation Solution
A light-emitting element with a carrier transport layer comprising inorganic nanoparticles and a ligand with at least two coordination functional groups, which coordinates with the nanoparticles, enhancing dispersibility and stability in both polar and non-polar solvents, thereby improving liquid resistance and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the particle size of inorganic nanoparticles is decreased to improve carrier transport efficiency, then the band gap is increased which facilitates carrier injection, but the dispersibility is decreased and agglomeration is more likely to occur
Solution Approach 1:
The patent introduces ligands as intermediary substances that coordinate to the surface of inorganic nanoparticles. These ligands act as mediators between the nanoparticles and the solvent environment, preventing direct nanoparticle-nanoparticle interactions that cause agglomeration. The ligands provide steric and/or electrostatic repulsion forces that maintain nanoparticle dispersion stability while allowing the nanoparticles to retain their small size for efficient carrier transport.
Solution Approach 2:
The patent creates a composite structure by combining inorganic nanoparticles with organic ligands to form a hybrid material system. This composite approach allows the inorganic core to provide carrier transport functionality while the organic ligand shell provides dispersibility and stability. The synergistic combination resolves the contradiction between small particle size requirements and dispersion stability requirements.
2Stability of the object's composition
If a known ligand typically used in quantum dot dispersant liquid is used to enhance dispersibility, then the dispersibility is improved, but the liquid resistance with respect to non-polar solvent is low
Solution Approach 1:
The patent changes the chemical parameters of the ligand by selecting specific functional groups (carboxylic acid, phosphonic acid, or phosphine oxide) with appropriate polarity and coordination ability. These parameter changes in ligand chemistry enable the carrier transport layer to resist both polar and non-polar solvents while maintaining dispersibility. The selected ligands have optimal balance between solubility in polar solvents and resistance to non-polar solvents.
3Reliability
If inorganic nanoparticles are used for the carrier transport material, then carrier transport efficiency is improved, but the carrier transport layer may deteriorate or dissolve when exposed to solvents of different polarities
Solution Approach 1:
The ligand acts as a protective intermediary layer between the inorganic nanoparticles and the solvent environment. This intermediary layer prevents direct contact between the solvent and nanoparticle surfaces, thereby preventing dissolution and deterioration. The ligand forms a stable coordination complex with the nanoparticle surface, creating a protective barrier that maintains layer integrity during subsequent processing steps involving solvents of different polarities.
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 solution provides a light-emitting element with high liquid resistance and reliability by preventing the carrier transport layer from deteriorating or dissolving in polar and non-polar solvents, ensuring stable performance.
Implementation Method 1
the ligand is a monomer including at least two coordination functional groups of at least one type, the at least two coordination functional groups being configured to coordinate to the plurality of inorganic nanoparticles
Data Source
AI summary
A light-emitting element includes a cathode electrode; an anode electrode an EML disposed between the cathode electrode and the anode electrode; and an ETL, disposed between the cathode electrode and the EML. The ETL includes a plurality of inorganic nanoparticles having carrier transport properties and a ligand. The ligand is a monomer including at least two coordination functional groups of at least one type for coordinating to the plurality of inorganic nanoparticles.