OLED Layer Structure for Recombination Shift and Longer Service Life
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Solution Overview
Problem
The service life of existing active-matrix organic light-emitting diode (AMOLED) display screens is short, affecting their further popularization due to premature degradation of the light-emitting layer and electron transport layer structures.
Innovation Solution
Incorporating a first material with lower electron mobility in both the hole blocking layer and electron transport layer to reduce electron migration rate, shifting the recombination area from the interface between the light emitting layer and electron blocking layer to the electron transport layer, thereby widening the recombination area and minimizing structural impact, thus prolonging the device's service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional materials are used in the electron transport layer and hole blocking layer, then the device structure is simple and manufacturing is easier, but the service life of the OLED device is short due to degradation at the light emitting layer interface
Solution Approach 1:
The electron transport layer is divided into two distinct sub-layers: a first electron transport layer adjacent to the light emitting layer with lower electron mobility, and a second electron transport layer away from the light emitting layer with higher electron mobility. This segmentation allows the device to protect the light emitting layer interface while maintaining overall electron transport efficiency, thereby extending service life without significantly complicating the manufacturing process.
Solution Approach 2:
Different regions of the electron transport layer are assigned different material properties: the first electron transport layer near the light emitting layer uses materials with lower electron mobility to reduce electron accumulation and degradation at the interface, while the second electron transport layer uses materials with higher electron mobility to ensure efficient electron transport to the cathode. This local differentiation optimizes both reliability and performance.
2Productivity
If electron mobility in the electron transport layer is increased to improve electron transport efficiency, then the light emitting efficiency improves, but the service life decreases due to accelerated degradation at the light emitting layer interface
Solution Approach 1:
The electron transport layer is segmented into two functional zones with different electron mobility characteristics. The first electron transport layer has lower electron mobility to protect the light emitting layer interface from excessive electron flux and degradation, while the second electron transport layer has higher electron mobility to maintain efficient electron transport to the cathode, thus resolving the contradiction between transport efficiency and service life.
Solution Approach 2:
The patent applies different material qualities at different locations within the electron transport layer. Materials with lower electron mobility are used in the region adjacent to the light emitting layer to reduce degradation, while materials with higher electron mobility are used in the region closer to the cathode to maintain transport efficiency. This local quality differentiation allows simultaneous optimization of both service life and electron transport 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 solution significantly prolongs the service life of the organic light-emitting diode device by reducing electron mobility and shifting the recombination area, leading to slower brightness decay and improved durability under various environmental conditions without affecting light-emitting performance.
Implementation Method 1
the first material has a lower electron mobility; then the electron transport layer is made of the first material, which can reduce the electron mobility of the electron transport layer
Implementation Method 2
the hole blocking layer is configured to block the transport of the hole
Implementation Method 3
In the light emitting layer, the recombination area of the electron and hole can be shifted... Therefore, the recombination reaction occurring in the recombination area does not affect the structures of the light emitting layer and the electron blocking layer
Data Source
AI summary
Disclosed is an organic light-emitting diode device including: an electron transport layer, a hole blocking layer and a light emitting layer arranged in a stacked manner; the hole blocking layer includes a first material, and the electron transport layer includes the first material.