OLED Red Emitter Host-Dopant Configuration for Efficiency and Lifespan
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Solution Overview
Problem
Current organic light emitting diodes (OLEDs) face challenges in achieving high luminous efficiency and long luminous lifespan due to limitations in exciton generation efficiency and energy transfer efficiency in the emitting material layer, particularly with fluorescent materials showing low efficiency and phosphorescent materials having short lifespan.
Innovation Solution
An OLED structure incorporating a red emitting material layer with specific compounds, including a first compound represented by Formula 1-1, a second compound, and a third compound, which are organometallic complexes with rigid chemical conformation, enhancing luminous efficiency and lifespan by optimizing the host and dopant configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If fluorescent material is used as dopant, then the OLED can be manufactured with simpler materials, but luminous efficiency is low because only singlet exciton energy is utilized
Solution Approach 1:
The patent employs a composite emitting material layer containing both fluorescent dopant and phosphorescent dopant within the same host material. This composite approach allows the system to utilize both singlet and triplet exciton energy, achieving high luminous efficiency while maintaining manufacturability through a unified layer structure rather than separate fluorescent and phosphorescent layers
2Loss of energy
If phosphorescent material is used as dopant, then luminous efficiency is improved by utilizing both singlet and triplet exciton energy, but luminous lifespan becomes short
Solution Approach 1:
The patent applies local quality by assigning different functional roles to different dopants within the emitting material layer. The phosphorescent dopant locally handles triplet exciton energy conversion with high efficiency, while the fluorescent dopant handles singlet exciton energy. This localized functional distribution allows each dopant to operate in its optimal performance regime, achieving both high luminous efficiency and extended lifespan
3Device complexity
If the emitting material layer uses conventional host and dopant configuration, then the structure is simple, but exciton generation efficiency and energy transfer efficiency are insufficient
Solution Approach 1:
The patent optimizes key parameters of the emitting material layer including the weight ratios of host to dopants, the specific composition ratios of fluorescent and phosphorescent dopants, and the molecular structure parameters of the host material. These parameter optimizations enhance exciton generation efficiency and energy transfer efficiency while maintaining a relatively simple three-component layer structure
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 proposed OLED structure significantly improves luminous efficiency and lifespan by utilizing a red emitting material layer with specific organometallic compounds, leading to better exciton utilization and prolonged light emission.
Implementation Method 1
a phosphorescent material can show high luminous efficiency since it uses triplet exciton energy as well as singlet exciton energy in the luminous process
Implementation Method 2
a fluorescent material as the dopant uses only singlet exciton energy in the luminous process
Implementation Method 3
the luminous efficiency and the luminous lifespan of the OLED are affected by the exciton generation efficiency in the host and the energy transfer efficiency from the host to the dopant
Data Source
AI summary
An organic light emitting diode and an organic light emitting device including the organic light emitting diode are discussed. The organic light emitting diode can include a first compound represented by the following formula, a second compound as a p-type host, and a third compound as an n-type host in an emitting material layer. As a result, the organic light emitting diode and the organic light emitting device have advantages in the driving voltage, the luminous efficiency and the lifespan.