Rare Earth Metal Interlayer for OLED Electron Injection
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Solution Overview
Problem
Existing organic light-emitting display panels face poor performance due to high interfacial energy barriers between the electron transport layer and the cathode, leading to low electron injection capacity.
Innovation Solution
Incorporating a rare earth transition metal, such as ytterbium, between the surface of the cathode and the electron transport layer near the organic light-emitting layer to lower the interfacial energy barrier, thereby improving electron injection and overall panel performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional organic light-emitting display panel structure is used without modifying the electrode interfaces, then the device structure remains simple, but the interfacial energy barrier between the electron transport layer and the cathode is high, resulting in poor electron injection capacity
Solution Approach 1:
A rare earth transitional metal layer is introduced as an intermediary between the cathode and the electron transport layer. This intermediate layer acts as a mediator to facilitate electron injection by providing a gradual energy level transition, thereby reducing the interfacial energy barrier and improving electron injection capacity without fundamentally changing the overall device structure
Solution Approach 2:
The energy barrier parameter at the cathode-electron transport layer interface is modified by introducing the rare earth transitional metal. This changes the energy level alignment and reduces the interfacial energy barrier, enabling improved electron injection capacity while maintaining the basic device architecture
2Duration of action of stationary object
If the interfacial energy barrier between the electron transport layer and the cathode is high, then the device structure remains conventional, but the working voltage is high and the lifetime is short
Solution Approach 1:
The rare earth transitional metal serves as an intermediary that improves carrier balance at the interface, reducing recombination losses and improving efficiency. This leads to lower operating voltage requirements and extended device lifetime through improved stability and reduced degradation mechanisms
3Productivity
If the interfacial energy barrier is not reduced, then the device structure remains simple, but the carrier balance is poor and light-emitting efficiency is low
Solution Approach 1:
The rare earth transitional metal layer acts as an intermediary that improves carrier balance by providing matched energy levels for both electron and hole transport. This enhances the efficiency of exciton formation and light emission, achieving high light-emitting efficiency with a relatively simple additional interface layer
Solution Approach 2:
The interface is constructed as a composite structure combining the cathode material, rare earth transitional metal, and electron transport layer. This composite interface provides synergistic effects that improve carrier balance and light-emitting efficiency beyond what any single material could achieve alone
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 enhances electron injection capacity, reduces the working voltage, and extends the lifetime of the organic light-emitting display panel by facilitating carrier balance and improving light-emitting efficiency.
Implementation Method 1
lowering the interfacial energy barrier between the electron transport layer and the cathode
Implementation Method 2
electrons and holes recombine to generate excitons. The excitons are unstable, and energy can be released. The energy is transferred to the molecules of the organic light-emitting material in the light-emitting layer, so that the molecules transit from a ground state to an excited state. The excited state is very unstable, and thus the excited molecules return to the ground state from the excited state, so that a light emitting phenomenon appears due to radiative transition
Data Source
AI summary
Embodiments of the present disclosure disclose an organic light-emitting display panel and an organic light-emitting display device. The organic light-emitting display panel includes: a substrate; a first electrode and a second electrode that are stacked, wherein the first electrode and the second electrode are both located on the same side of the substrate; an organic light-emitting layer, which is located between the first electrode and the second electrode; an electron transport layer, which is located between the organic light-emitting layer and the second electrode; wherein, a rare earth transitional metal is also contained at any location between the surface of the second electrode away from the organic light-emitting layer and the surface of the electron transport layer near to the organic light-emitting layer.