OLED Hole Transport Units with Varying Mobility Reduce Crosstalk
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Solution Overview
Problem
Existing OLED display panels suffer from increased crosstalk and degraded display performance due to undesired light emission from adjacent subpixels, as carriers drift laterally through the hole transport layer when one subpixel is turned on, causing adjacent subpixels to emit light unintentionally.
Innovation Solution
The OLED display panel incorporates hole transport units corresponding to light-emitting devices of different colors with varying mobility, reducing lateral current and preventing unwanted light emission by making it difficult for holes to transit between these units, thereby suppressing undesired light from adjacent subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common hole transport layer is used across all subpixels, then the device structure is simple and manufacturing is easy, but carriers drift laterally causing crosstalk between adjacent subpixels
Solution Approach 1:
The hole transport layer is segmented into multiple independent hole transport units, each corresponding to a specific subpixel. These units are isolated from each other by insulating layers, preventing lateral carrier drift between adjacent subpixels while maintaining individual control over hole transport in each subpixel region.
Solution Approach 2:
Different hole transport units are assigned different materials with optimized properties tailored to each subpixel's requirements. This allows local optimization of hole transport characteristics for each subpixel while preventing interference between adjacent subpixels through material-based isolation.
2Object-affected harmful factors
If hole transport units with different mobility are used for different colored light-emitting devices, then crosstalk is reduced, but device complexity increases
Solution Approach 1:
Each hole transport unit is assigned a specific material with mobility characteristics optimized for its corresponding light-emitting device color. This local differentiation suppresses crosstalk by creating mobility barriers at interfaces between different colored subpixels, while the modular unit structure manages the complexity through systematic material assignment.
Solution Approach 2:
The hole transport layer is constructed as a composite structure with different material compositions in adjacent units. This composite approach enables tailored hole transport properties for each subpixel type while the repeating unit pattern keeps the overall device architecture manageable despite the material diversity.
3Area of stationary object
If spacers are added on the pixel defining layer to improve packing effect, then subpixel packaging is improved, but lateral carrier drift and crosstalk increase
Solution Approach 1:
The continuous hole transport layer is divided into discrete units separated by insulating barriers. This segmentation prevents the formation of continuous lateral carrier pathways that would otherwise be created by adding spacers, while still allowing close packing of subpixels through the modular unit arrangement.
Solution Approach 2:
Insulating layers are introduced as intermediary structures between adjacent hole transport units. These intermediaries block lateral carrier drift while allowing the subpixels to be closely packed, effectively decoupling the packing density from crosstalk generation.
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 solution effectively reduces crosstalk and enhances display performance by minimizing the number of holes transported to adjacent subpixels, leading to improved luminous efficiency and reduced undesired light emission.
Implementation Method 1
the hole transport units corresponding to the light-emitting devices of two different colors have different mobility
Data Source
AI summary
An organic light-emitting diode (OLED) display panel and an OLED display device are provided. The OLED display panel comprises a first substrate; a first electrode layer disposed on the first substrate and including a plurality of first electrodes; a first hole transport layer disposed on a surface of the first electrode layer far away from the first substrate, and including a plurality of hole transport units, wherein the plurality of hole transport units are arranged in correspondence with the plurality of first electrodes respectively; a plurality of light-emitting devices disposed on a surface of the first hole transport layer far away from the first electrode layer, wherein the plurality of the light-emitting devices are arranged in correspondence with the plurality of hole transport units respectively, and the hole transport units corresponding to the light-emitting devices of two different colors have different mobility; and a second electrode layer.