OLED Exciton Transfer via Host Compound Mediator
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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 existing fluorescent materials, particularly those using singlet excitons, and phosphorescent materials with metal complexes that have short lifespans.
Innovation Solution
An OLED structure incorporating a first compound with delayed fluorescent properties and a second compound with fluorescent properties, where the first compound efficiently transfers exciton energy to the second compound, enhancing luminous efficiency and color purity, and optionally including a third compound as a host to improve charge injection and exciton generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescent materials with metal complexes are used to improve luminous efficiency, then luminous efficiency is improved, but luminous lifespan deteriorates
Solution Approach 1:
The patent uses a host compound as an intermediary to transfer exciton energy to the emitting material. The host compound (Formula 7 or 9) accepts excitons and transfers energy to the emitting material (Formula 1 or 5), enabling efficient energy transfer while avoiding direct use of short-lived metal complexes, thus extending device lifespan while maintaining high luminous efficiency
Solution Approach 2:
The patent changes the chemical structure parameters by defining specific molecular formulas with variable groups (R1-R28 representing different functional groups). This allows optimization of energy levels, exciton transfer efficiency, and material stability, achieving both high luminous efficiency and extended lifespan through parameter optimization rather than relying on metal complexes
2Device complexity
If fluorescent materials using singlet excitons are used, then device simplicity is maintained, but luminous efficiency deteriorates
Solution Approach 1:
The host compound acts as a mediator that facilitates triplet exciton utilization. The host accepts triplet excitons and transfers energy to the emitting material, enabling the system to utilize both singlet and triplet excitons without requiring complex phosphorescent metal complexes, thus maintaining relative simplicity while achieving high luminous efficiency
Solution Approach 2:
The patent creates a composite emitting material system combining the host compound (Formula 7 or 9) with the emitting material (Formula 1 or 5). This composite structure enables synergistic effects where the host provides exciton management and the emitting material provides efficient light emission, achieving high luminous efficiency without excessive complexity
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 achieves improved luminous efficiency, color purity, and extended luminous lifetime by efficiently transferring exciton energy and balancing hole and electron transfer, resulting in enhanced performance of the OLED.
Implementation Method 1
the first compound efficiently transfers exciton energy to the second compound, enhancing luminous efficiency and color purity
Implementation Method 2
an organic light emitting diode (OLED) that has beneficial luminous properties
Data Source
AI summary
An organic light diode (OLED) and an organic light emitting device comprising the OLED (e.g., a display device or a lighting device) are described. The OLED can comprise at least one emitting material layer including a first compound where an alkyl group is substituted to a specific position of an electron donor moiety and a second compound of a boron-based fluorescent material. Luminous properties in the OLED and the device can be improved as excitons generated at the first compound are transferred efficiently to the second compound.