Exciplex Composition for Low Voltage OLEDs
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Solution Overview
Problem
Organic light-emitting devices (OLEDs) face challenges in achieving low driving voltage, high efficiency, high brightness, and long lifespan.
Innovation Solution
A composition comprising an exciplex formed by a donor compound and an acceptor compound, with specific emission wavelength, decay time, and photoluminescence stability, is used to create a thin film and organic light-emitting device, which includes a thin film with a low driving voltage, high emission efficiency, and long lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If conventional OLED materials and structures are used, then basic light emission is achieved, but driving voltage remains high and efficiency is limited
Solution Approach 1:
The patent applies parameter changes by carefully controlling the emission wavelength (390-490 nm range) and decay time (≥100 ns) of the exciplex to optimize device performance. By adjusting these physical parameters within specific ranges, the invention achieves low driving voltage while maintaining stable device operation and high efficiency
Solution Approach 2:
The patent uses composite materials by combining donor and acceptor compounds to form an exciplex system. This composite approach allows the material to exhibit properties that neither component possesses alone, achieving both low driving voltage and high emission efficiency simultaneously through the synergistic interaction between donor and acceptor molecules
2Speed
If exciplex with short decay time is used, then fast response is achieved, but delayed fluorescence ratio decreases
Solution Approach 1:
The patent optimizes the decay time parameter to be ≥100 ns, which is sufficiently long to generate detectable delayed fluorescence (≥10% ratio) while still maintaining fast response characteristics for OLED operation. This parameter optimization resolves the contradiction between response speed and delayed fluorescence utilization
3Illumination intensity
If exciplex with high emission intensity is used, then brightness is improved, but photoluminescence stability decreases
Solution Approach 1:
The patent specifies the emission wavelength within the 390-490 nm range and requires photoluminescence stability ≥59%, optimizing these parameters to achieve high brightness while maintaining adequate operational stability. The controlled wavelength range ensures high emission intensity while the stability requirement guarantees reliable device performance
Solution Approach 2:
The patent accepts moderate photoluminescence stability (≥59%) in exchange for achieving high emission intensity and brightness, similar to using materials with limited lifespan for specific high-performance applications. This approach prioritizes brightness performance while maintaining acceptable device longevity
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 composition enables OLEDs to operate with low driving voltage, high efficiency, and long lifespan by optimizing the exciplex properties, resulting in improved performance and durability.
Implementation Method 1
a maximum emission wavelength λmax(Ex) in a photoluminescence spectrum of the exciplex is about 390 nanometers or greater and about 490 nanometers or less
Implementation Method 2
a decay time Tdecay(Ex) of delayed fluorescence in a time-resolved photoluminescence spectrum of the exciplex is about 100 nanoseconds or greater
Data Source
AI summary
A composition including a donor compound and an acceptor compound, wherein the donor compound and the acceptor compound form an exciplex having characteristics described in the specification.