OLED Exciplex Elimination Layer for Carrier Confinement
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Solution Overview
Problem
The luminous efficiency of OLED devices is reduced due to the production of new luminous species between blue and red or green emissive layers, leading to decreased performance.
Innovation Solution
Incorporating an exciplex elimination layer between the red and/or green emissive layers and the blue emissive layer to confine carriers within the red and/or green emissive layers, preventing exciplex formation and ensuring efficient light emission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If red and green emissive layers are placed adjacent to blue emissive layer, then device structure is simplified, but new luminous species (exciplex) forms between layers causing reduced luminous efficiency
Solution Approach 1:
An electron transport layer is introduced as an intermediary between the red/green emissive layers and the blue emissive layer. This intermediate layer prevents direct contact between the emissive layers, thereby eliminating exciplex formation while maintaining the simplified adjacent structure configuration. The electron transport layer acts as a buffer that allows structural simplicity without sacrificing luminous efficiency.
2Reliability
If carriers are allowed to move freely between emissive layers, then carrier distribution is improved, but exciplex formation occurs reducing current and external quantum efficiency
Solution Approach 1:
The device is segmented into distinct functional zones by introducing the electron transport layer between emissive layers. This segmentation creates clear boundaries that confine carriers within their respective emissive layers, preventing inter-layer carrier migration that would lead to exciplex formation. Each layer maintains its functional independence while contributing to overall device performance.
3Ease of manufacture
If emissive layers are placed in direct contact, then manufacturing process is simplified, but chromaticity stability deteriorates due to exciplex formation
Solution Approach 1:
The electron transport layer serves as a mediator that physically separates the emissive layers, preventing direct contact and the resulting exciplex formation that would alter chromaticity. This intermediate layer maintains stable color emission from each emissive layer while being easily integrated into the existing manufacturing process sequence.
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 enhances luminous efficiency by ensuring carriers recombine in the intended emissive layers, reducing operating voltage and improving current and external quantum efficiency while maintaining chromaticity.
Implementation Method 1
the exciplex elimination layer is configured to confine carriers in at least one of the red and green emissive layers
Implementation Method 2
An Organic Light Emitting Diode (OLED) is such a display device in which a fluorophor or phosphor organic compound is electrically excited to emit light
Implementation Method 3
An Organic Light Emitting Diode (OLED) is such a display device in which a fluorophor or phosphor organic compound is electrically excited to emit light
Data Source
AI summary
An organic light emitting diode, which includes a substrate, a first electrode, at least one of red and green emissive layers, a blue emissive layer, a second electrode, and an exciplex elimination layer that is formed between at least one of the red and green emissive layers and the blue emissive layer; the exciplex elimination layer acts to confine carriers in at least one of the red and green emissive layers.