OLED Display Panel Hole Transport Layer Lateral Drift
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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 when one subpixel is turned on, caused by lateral carrier drift through the hole transport layer.
Innovation Solution
The OLED display panel incorporates a hole transport layer formed by mixing first and second hole transport materials with different carrier mobility, reducing lateral drift velocity and subsequent lateral current, thereby suppressing undesired light emission from adjacent subpixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional hole transport layer is used in OLED display panel, then the structure is simple and easy to manufacture, but lateral carrier drift occurs causing increased crosstalk and degraded display performance
Solution Approach 1:
The hole transport layer is segmented into multiple sub-layers with different materials (first hole transport layer with first hole transport material, second hole transport layer with second hole transport material having different carrier mobility). This segmentation allows each layer to perform specific functions: the first layer provides basic hole transport, while the second layer with different mobility characteristics suppresses lateral carrier drift, thereby reducing crosstalk and improving display performance without requiring complete redesign of the entire structure.
Solution Approach 2:
The patent employs composite materials by combining different hole transport materials with distinct carrier mobility properties in the hole transport layer. This composite structure leverages the complementary characteristics of each material to achieve both effective hole transport toward the light-emitting layer and suppression of lateral drift, resolving the contradiction between maintaining simple structure and improving display performance.
2Productivity
If hole transport layer allows high carrier mobility, then hole transport efficiency is improved, but lateral drift increases causing undesired light emission from adjacent subpixels
Solution Approach 1:
The patent applies local quality by creating different hole transport layers with distinct material properties at different locations within the hole transport structure. The first hole transport layer uses material with certain mobility for efficient vertical transport, while the second layer uses material with different mobility characteristics specifically to suppress lateral drift. This localized differentiation allows simultaneous achievement of high transport efficiency and low lateral current.
Solution Approach 2:
By dividing the hole transport layer into multiple segments with different materials, the patent enables each segment to optimize for its specific function: one segment prioritizes vertical hole transport efficiency, while another segment prioritizes suppression of lateral carrier drift, thereby resolving the contradiction between productivity and harmful lateral current 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 undesired light emission and improves luminous efficiency and display performance by minimizing carrier injection into adjacent light-emitting devices, thereby enhancing the overall performance of the OLED display panel.
Implementation Method 1
a hole transport layer disposed on a surface of the first electrode layer far away from the first substrate and formed by a first hole transport material and a second hole transport material having different carrier mobility
Implementation Method 2
a plurality of light-emitting devices disposed on a surface of the hole transport layer far away from the first electrode layer and arranged in correspondence with the plurality of first electrodes respectively
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 hole transport layer disposed on a surface of the first electrode layer far away from the first substrate, and formed by a first hole transport material and a second hole transport material having different carrier mobility; a plurality of light-emitting devices disposed on a surface of the hole transport layer far away from the first electrode layer and arranged in correspondence with the plurality of first electrodes respectively; an electron transport layer disposed on a surface of the plurality of light-emitting devices far away from the hole transport layer; and a second electrode layer disposed on a surface of the electron transport layer far away from the plurality of light-emitting devices.