Charge Transport Layer Preparation via Functional Material Mediation
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Solution Overview
Problem
Existing charge transport layers formed from colloidal metal oxide nanocrystals suffer from low exciton mobility and exciton dissociation due to local defects, primarily caused by uncontrolled deposition processes.
Innovation Solution
A preparation method involving the formation of film layers using solutions containing functional and charge transport materials, where the functional material with electron-donating groups bonds with metal cation dangling bonds on the charge transport material surfaces, followed by heat treatment to remove the functional material, resulting in an orderly arrangement of metal oxide nanomaterials and reduced defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If colloidal metal oxide nanocrystals are used to form charge transport layer, then large-area device production is enabled, but local defects occur due to uncontrolled deposition process
Solution Approach 1:
The patent introduces an organic functional material as an intermediary substance that mediates between the colloidal metal oxide nanocrystals and the deposition process. This functional material adsorbs onto the nanocrystal surfaces, providing steric stabilization and preventing uncontrolled aggregation during deposition, thereby enabling large-area production while maintaining film uniformity and reducing local defects.
Solution Approach 2:
The patent modifies the deposition process by changing key parameters including the composition of the colloidal suspension (adding functional materials), surface treatment conditions, and deposition parameters. These parameter changes control the nucleation and growth of nanocrystals during deposition, preventing local agglomeration and ensuring uniform film formation across large areas.
2Ease of manufacture
If colloidal metal oxide nanocrystals are deposited to form charge transport layer, then device fabrication is simplified, but exciton mobility is reduced due to local defects
Solution Approach 1:
The organic functional material serves as a mediator that improves exciton mobility by providing well-defined interfaces and reducing defect states. The functional material creates a more ordered structure at the nanocrystal surfaces, facilitating better charge and exciton transport while maintaining the simplicity of the solution-processing fabrication method.
3Device complexity
If conventional deposition process is used for charge transport layer, then process simplicity is maintained, but exciton dissociation occurs at defects reducing device efficiency
Solution Approach 1:
The patent applies preliminary treatment to the colloidal nanocrystals before deposition, including surface functionalization and controlled assembly. This preliminary action prepares the nanocrystals to form defect-minimized structures during deposition, preventing exciton dissociation sites from forming in the first place, thereby reducing energy loss while keeping the overall process relatively simple.
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 method enhances exciton mobility and prevents exciton dissociation, leading to high-efficiency charge transport layers with stable performance and improved luminous efficiency in light-emitting diodes.
Implementation Method 1
the electron-donating group is capable of being bonded with the metal cation dangling bond
Implementation Method 2
removing the functional material to obtain a charge transport layer
Data Source
AI summary
The present application provides a preparation method of a charge transport layer, which includes steps of: forming a first film layer by a first solution containing a functional material, forming a second film layer by a second solution containing a charge transport material, the first film layer and the second film layer are in contact with each other, or forming a mixed film layer by a mixed solution of the first solution and the second solution; and removing the functional material to obtain a charge transport layer. The functional material is an organic substance containing an electron-donating group, a surface of the charge transport material has a metal cation dangling bond, and the electron-donating group is capable of being bonded with the metal cation dangling bond.