Inorganic Electroluminescent Device Insulating Layer Uniform Emission
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Solution Overview
Problem
Current inorganic electroluminescent devices with inorganic electron transport layers exhibit partial light emission limited to the edges of the electron injecting electrode, leading to non-uniform light emission across the entire light-emitting surface, and increasing voltage to improve electron injection results in undesirable phenomena like bubbling and electrode separation.
Innovation Solution
Incorporating a thin insulating layer between the electron injecting electrode and the inorganic electron transport layer to eliminate fringe field effects, using materials like LiF, BaF2, TiO2, or organic polymers to form the insulating layer, which reduces the total thickness and enhances electron tunneling for uniform light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If voltage is increased to improve electron injection efficiency, then electron injection is enhanced, but undesirable phenomena such as bubbling and electrode separation occur
Solution Approach 1:
An insulating layer is introduced as an intermediary between the electron injecting electrode and the inorganic electron transport layer. This insulating layer mediates the electron injection process, enabling efficient electron injection without requiring high voltage that would cause bubbling and electrode separation. The insulating layer acts as a buffer that facilitates controlled electron transfer while maintaining electrode stability.
2Device complexity
If no insulating layer is used, then device structure is simpler, but fringe field effects cause non-uniform light emission
Solution Approach 1:
The insulating layer serves as a mediator that eliminates fringe field effects at the edges of the electron injecting electrode. By introducing this intermediate layer, the electric field distribution is smoothed out, resulting in uniform light emission across the entire light-emitting surface. The insulating layer acts as a field uniformizer that prevents edge effects while maintaining a relatively simple device structure.
3Reliability
If insulating layer thickness is increased, then electrode separation is prevented, but electron tunneling efficiency decreases
Solution Approach 1:
The thickness of the insulating layer is optimized to a specific range (0.5-2 nm) to achieve the desired balance. By carefully controlling this parameter, the insulating layer is thick enough to prevent electrode separation and stabilize the device, yet thin enough to allow efficient electron tunneling. This parameter optimization resolves the contradiction between electrode stability and electron injection efficiency.
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
The introduction of a thin insulating layer ensures efficient light emission from the entire light-emitting surface, reducing turn-on voltage and increasing maximum luminance, while preventing electrode separation and improving device reliability and stability.
Implementation Method 1
enhances electron tunneling for uniform light emission
Implementation Method 2
Inorganic electroluminescent devices are devices that utilize collision of electrons that have been accelerated by a high electric field to emit light
Data Source
AI summary
Disclosed is an inorganic electroluminescent device. The inorganic electroluminescent device comprises a hole transport layer, a light-emitting layer, an inorganic electron transport layer and an electron injecting electrode sequentially formed on a hole injecting electrode wherein an insulating layer is formed between the electron injecting electrode and the inorganic electron transport layer.Further disclosed are a method for fabricating the electroluminescent device and an electronic device comprising the electroluminescent device.The inorganic electroluminescent device achieves uniform light emission from the entire light-emitting surface of the device, resulting in an improvement in the reliability and stability of the device. The inorganic electroluminescent device is suitable for use in the manufacture of electronic devices, including display devices, illuminators and backlight units.