Metal Complex Hole Injection Layer for OLED Voltage Stability
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Solution Overview
Problem
There is a need to improve the performance of organic electronic devices, specifically organic light-emitting diodes (OLEDs), by enhancing the characteristics of the hole injection layer to achieve lower operating voltage, improved voltage stability over time, and extended lifetime, while also enabling deposition through vacuum thermal evaporation suitable for mass production.
Innovation Solution
The use of a hole injection layer comprising a metal complex with a metal ion selected from Ce(IV), Hf(IV), or Zr(IV), and an anionic ligand with at least 14 covalently bound atoms, arranged between the emission layer and the anode layer, where the anode layer consists of multiple sub-layers including a first anode sub-layer with a work function between 4 and 6 eV and a transparent conductive oxide sub-layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional hole injection layers are used in OLEDs, then the device can be manufactured with standard materials and processes, but the operating voltage is high and voltage stability over time is poor
Solution Approach 1:
The patent changes the chemical composition parameters of the hole injection layer by incorporating metal complexes with specific properties (Ce(IV), Hf(IV), or Zr(IV) metal ions coordinated with organic ligands). This parameter change in material composition directly improves both operating voltage characteristics and voltage stability over time, resolving the contradiction between energy efficiency and reliability.
2Reliability
If complex metal complexes are used to improve hole injection performance, then operating voltage and stability improve, but the manufacturing process becomes more difficult
Solution Approach 1:
The patent replaces complex multi-step deposition processes with a simplified vacuum thermal evaporation process. The metal complexes are designed to be amorphous materials that can be deposited directly from vapor phase, substituting mechanical/chemical complexity with a straightforward physical vapor deposition process suitable for mass production.
3Productivity
If standard deposition processes are used, then mass production is feasible, but the thermal stability of the materials is insufficient
Solution Approach 1:
The patent creates composite materials by coordinating metal ions (Ce(IV), Hf(IV), or Zr(IV)) with organic ligands containing specific functional groups. This composite structure combines the thermal stability of metal centers with the processability of organic molecules, enabling both high thermal stability for mass production and suitability for vacuum thermal evaporation deposition.
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 results in superior performance of organic electronic devices in terms of operating voltage, voltage stability, and lifetime, with the metal complex and matrix compound exhibiting thermal stability suitable for mass production deposition.
Implementation Method 1
providing compounds which can be deposited through vacuum thermal evaporation under conditions suitable for mass production
Implementation Method 2
the first anode sub-layer comprises a first metal having a work function in the range of ≥ 4 and ≤ 6 eV
Data Source
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AI summary
The present invention relates to organic electronic device comprising a substrate, an anode layer, a cathode layer, at least one first emission layer, and a hole injection layer, wherein the hole injection layer comprises a metal complex, wherein the metal complex comprises a metal ion M selected from Ce(IV), Hf(IV) or Zr(IV) as well as a metal complex.