Lanthanide Oxide Anode for OLED Charge Injection
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Solution Overview
Problem
Existing OLEDs face issues with low injection efficiency due to narrow emission ranges in Alq3 and α-NPD layers, and weak interface coupling between ITO and MoO3, leading to overall efficiency limitations.
Innovation Solution
Incorporating a lanthanide oxide doped with conductive materials like titanium and rubidium as the anode, and hafnium oxynitride as the cathode, with an electron injection layer and a variable thickness light emission layer to enhance charge transport and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If Alq3 and α-NPD layers are used in OLED, then device structure is simplified, but emission range becomes narrow and injection efficiency decreases
Solution Approach 1:
The patent divides the OLED structure into multiple functional layers with specific materials assigned to each layer. The hole injection layer uses MoO3 with optimized thickness, the hole transport layer uses α-NPD, the emission layer uses Alq3, and the electron transport layer uses Alq3. This segmentation allows each layer to be optimized independently for its specific function, resolving the contradiction between structural simplicity and injection efficiency.
Solution Approach 2:
The patent optimizes the thickness of the MoO3 hole injection layer to a specific range (5-20 nm) to achieve the lowest driving voltage and highest power conversion efficiency. This parameter optimization resolves the contradiction by finding the optimal thickness that balances structural simplicity with high injection efficiency.
2Ease of manufacture
If aluminum cathode is used, then device manufacturing is simplified, but electron injection efficiency becomes low
Solution Approach 1:
The patent introduces an electron transport layer made of Alq3 between the aluminum cathode and the emission layer. This intermediary layer facilitates efficient electron injection from the aluminum cathode into the emission layer, resolving the contradiction between manufacturing simplicity and electron injection efficiency.
3Device complexity
If ITO and MoO3 interface is used, then device structure is simplified, but interface coupling becomes weak reducing overall efficiency
Solution Approach 1:
The patent optimizes the thickness of the MoO3 layer at the ITO interface to a specific range (5-20 nm) to enhance interface coupling. This parameter optimization strengthens the electrical connection between ITO and the organic layers, resolving the contradiction between structural simplicity and energy efficiency by preventing charge accumulation and reducing energy loss.
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
Improves charge injection efficiency, broadens the wavelength range for balanced color emission, and increases the OLED's resistance to oxidation and water exposure, resulting in enhanced performance and longevity.
Implementation Method 1
The anode includes a lanthanide oxide. The lanthanide oxide is doped with a conductive material including at least one of rubidium and titanium
Implementation Method 2
Electrostatic forces bring the electrons and the holes together and they recombine near the light emitting layer, which causes a drop in energy levels and an emission of radiation in the range of visible light
Implementation Method 3
Cathodes generally comprise a material having a low work function such that a relatively small voltage causes the emission of electrons
Data Source
AI summary
An organic light emitting device including an anode including a lanthanide oxide. The lanthanide oxide is doped with a conductive material including rubidium, titanium, or combinations thereof. The organic light emitting device further includes a cathode, an organic hole transport layer intermediate the anode and cathode, and an electron injection layer intermediate the anode and cathode.