Organic Light Emitting Diode Light Scattering Layer
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Solution Overview
Problem
Current organic electroluminescent devices face challenges in maximizing light extraction efficiency and maintaining device stability due to limitations in light scattering and charge transport layers, leading to suboptimal light emission and increased driving voltage.
Innovation Solution
Incorporating a light scattering layer with a specific compound structure between the light emitting layer and the cathode, which includes a p-type organic material layer with a light scattering structure, and optimizing the thickness and energy levels of p-type and n-type organic material layers to enhance charge balance and light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional charge transport layer structure is used, then device stability is maintained, but light extraction efficiency is suboptimal due to light absorption by the transport layers
Solution Approach 1:
The charge transport function is segmented into two separate layers: a first charge transport layer adjacent to the light emitting layer, and a second charge transport layer adjacent to the electrode. This segmentation allows the first layer to be optimized for light transmission while the second layer handles charge transport, reducing light absorption losses in the light extraction path.
Solution Approach 2:
The first charge transport layer acts as an intermediary between the light emitting layer and the second charge transport layer. It facilitates charge transport while being positioned to minimize light absorption, effectively mediating between the light emission function and the charge transport function.
2Reliability
If the thickness of charge transport layers is increased to improve charge transport, then charge balance improves, but light absorption increases and light extraction efficiency decreases
Solution Approach 1:
By dividing the charge transport function into two layers with different thicknesses and material compositions, the patent achieves adequate charge transport without excessive thickness in the light-blocking path. The first layer can be thinner since the second layer provides additional charge transport capacity.
Solution Approach 2:
Different regions of the charge transport system have different optical and electrical requirements. The first charge transport layer is optimized for light transmission (thinner, lower absorption), while the second charge transport layer is optimized for charge transport (can be thicker, different material properties).
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 improves light extraction efficiency by minimizing light absorption and maintaining device stability while reducing the driving voltage, thereby enhancing overall light emission performance.
Implementation Method 1
a light scattering layer provided between the light emitting layer and the cathode
Implementation Method 2
an organic electroluminescent device converts a current into visible light by injecting electrons and holes from two electrodes into an organic material layer
Implementation Method 3
An organic electroluminescent device converts a current into visible light by injecting electrons and holes from two electrodes into an organic material layer
Data Source
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AI summary
The present specification discloses an organic electroluminescent device including: an anode; a cathode; a light emitting layer provided between the anode and the cathode; and a light scattering layer provided between the light emitting layer and the cathode.