OLED Emission Layer Composition Using Exciplex Delayed Fluorescence
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Solution Overview
Problem
Existing organic light-emitting devices face challenges in achieving high luminescent efficiency and a long lifespan.
Innovation Solution
The use of a specific combination of compounds in the emission layer, including an iridium-free organometallic compound and other compounds forming an exciplex, with a decay time of delayed fluorescence in the time-resolved electroluminescence spectrum of about 50 ns or more, along with a particular electrode configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional emission layers are used in organic light-emitting devices, then device structure is simple, but luminescent efficiency is insufficient and lifespan is short
Solution Approach 1:
The emission layer employs a composite material system consisting of three distinct compounds: a host compound (Formula 1), a guest compound (Formula 2), and a third compound (Formula 3) containing specific functional groups. This composite structure enables exciplex formation between the host-guest pairs, generating delayed fluorescence with extended lifetimes (50 ns or more), thereby simultaneously improving device reliability and luminescent efficiency through material composition optimization rather than structural complexity
Solution Approach 2:
The invention optimizes the chemical structure parameters of the emission layer compounds, specifically incorporating compounds with particular molecular configurations (Formulas 1-3) that enable exciplex formation. By adjusting the chemical composition parameters—selecting specific host, guest, and third compounds with appropriate HOMO-LUMO energy levels and molecular geometries—the device achieves enhanced luminescent efficiency and extended operational lifespan without requiring complex device architecture
2Use of energy by moving object
If iridium-containing compounds are used for high luminescent efficiency, then brightness is improved, but device cost and complexity increase
Solution Approach 1:
The invention replaces expensive iridium-containing compounds with organic compounds that form exciplexes, utilizing readily available materials (host, guest, and third compounds with standard organic functional groups). Although individual organic compounds have shorter excited-state lifetimes, the exciplex mechanism generates delayed fluorescence that extends the effective emission lifetime to 50 ns or more, achieving cost-effective luminescent efficiency improvement through material substitution
Solution Approach 2:
The invention changes the chemical composition parameters from iridium-based phosphorescent compounds to organic exciplex-forming compounds. By selecting compounds with specific molecular structures (Formulas 1-3) and appropriate energy level alignments, the system achieves high luminescent efficiency through exciplex-mediated delayed fluorescence, eliminating the need for costly iridium while maintaining or improving performance
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 luminescent efficiency and extends the device's lifespan, providing improved performance characteristics.
Implementation Method 1
Organic light-emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response times, and excellent characteristics in terms of brightness, driving voltage, and response speed
Implementation Method 2
the first compound and the second compound form an exciplex, a decay time of delayed fluorescence in a time-resolved electroluminescence (TREL) spectrum of the organic light-emitting device is about 50 ns or more
Data Source
AI summary
Provided are an organic light-emitting device including a first compound, a second compound, and a third compound, and an electronic apparatus including the same. The organic light-emitting device includes a first electrode; a second electrode facing the first electrode; and an emission layer disposed between the first electrode and the second electrode, the emission layer including the first compound, the second compound, and the third compound.