Quantum Dot Light-Emitting Layer With Inorganic Ligand Conduction
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Solution Overview
Problem
The efficiency of carrier injection into quantum dots is low due to hopping conduction through organic ligands, which also degrades the reliability of quantum dots coordinating with organic ligands in existing light-emitting elements.
Innovation Solution
A light-emitting element with a light-emitting layer containing quantum dots and a mixed crystalline body made of ZnS, ZnSe, or Zn(OH)2, formed using an alkaline aqueous solution, to prevent carrier movement via organic ligands and enhance injection efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If organic ligands are used to coordinate with quantum dot surfaces, then quantum dots can be stabilized and processed, but carrier injection efficiency is low due to hopping conduction
Solution Approach 1:
The patent extracts and removes organic ligands from the quantum dot surface coordination by replacing them with inorganic ligands (S2-, Se2-, Te2-). This extraction of the harmful organic component eliminates the hopping conduction pathway while maintaining quantum dot stability through inorganic ligand coordination.
Solution Approach 2:
The patent changes the chemical parameter of the ligand material from organic to inorganic composition. By transforming the ligand type from carbon-based organic molecules to inorganic chalcogenide ions (S2-, Se2-, Te2-), the conduction mechanism changes from hopping to band conduction, dramatically improving carrier injection efficiency.
2Reliability
If organic ligands coordinate with quantum dots, then quantum dots can be formed and stabilized, but reliability degrades due to hopping conduction
Solution Approach 1:
The patent changes the ligand composition parameter from organic to inorganic, which fundamentally alters the energy transport mechanism. The inorganic ligands create a continuous band structure that enables efficient carrier conduction without the energy loss associated with hopping conduction through organic molecules.
Solution Approach 2:
The patent converts the previously harmful hopping conduction mechanism into a beneficial direct conduction mechanism by replacing organic ligands with inorganic ligands. The same ligand coordination function that previously caused energy loss through hopping is transformed into an efficient conduction pathway through the inorganic material's band structure.
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
This configuration improves carrier injection efficiency and reliability by reducing hopping conduction through organic ligands, enhancing the performance of the light-emitting layer.
Implementation Method 1
forming a light-emitting layer by using a plurality of quantum dots, and by using an alkaline aqueous solution containing at least one of a zinc source or a selenium source and containing a sulfur source
Data Source
AI summary
A light-emitting element includes the following: a first electrode and a second electrode; and a light-emitting layer disposed between the first electrode and the second electrode. The light-emitting layer includes a plurality of quantum dots, and a mixed crystalline body-containing at least one of ZnS or ZnSe and containing Zn(OH)2.