Polycyclic OLED Emitter Composition for Low-Voltage Long Life
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Solution Overview
Problem
Current organic electroluminescence display devices face challenges in reducing driving voltage and increasing emission efficiency and lifespan of light emitting elements.
Innovation Solution
A light emitting element is designed with a polycyclic compound in the emission layer, utilizing specific compounds represented by Formulas 1, 2, 3, and 4, which include a heavy atom like S, Se, or Te, and other substituents to enhance material stability and efficiency, forming a functional layer structure with a hole transport region and electron transport region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional organic electroluminescence materials are used, then the device can achieve basic light emission, but the driving voltage remains high and the lifespan is limited
Solution Approach 1:
The patent modifies molecular parameters by incorporating heavy atoms (S, Se, or Te) into the polycyclic compound structure, which changes the spin-orbit coupling parameter and enables efficient triplet exciton utilization through thermally activated delayed fluorescence (TADF), thereby improving both lifespan and reducing driving voltage
Solution Approach 2:
The patent employs composite material design by combining the polycyclic compound (Formula 1) with specific host materials (Formulas 2-4) in the emission layer, creating a synergistic system where the heavy atom effect of the polycyclic compound enhances TADF while the host materials provide structural stability and charge transport, resolving the contradiction between lifespan and energy consumption
2Productivity
If the emission efficiency is increased, then the device performance improves, but the material stability and lifespan are compromised
Solution Approach 1:
The patent applies local quality by introducing heavy atoms (S, Se, Te) specifically at strategic positions within the polycyclic compound structure (Formula 1) to enhance spin-orbit coupling and TADF efficiency locally, while the overall molecular framework maintains stability through the stable polycyclic core structure, thus achieving high emission efficiency without sacrificing material stability
Solution Approach 2:
The patent uses the polycyclic compound as an intermediary material in the emission layer that mediates between charge carriers and light emission, facilitating efficient energy transfer through TADF while the heavy atom effect acts as an intermediary mechanism to enable triplet exciton utilization, thereby achieving high emission efficiency with maintained material stability
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 results in improved long-life characteristics and emission efficiency of the light emitting element, with the polycyclic compound facilitating thermally activated delayed fluorescence and reducing reverse intersystem crossing, thereby extending the lifespan of the light emitting element.
Implementation Method 1
the polycyclic compound facilitating thermally activated delayed fluorescence
Implementation Method 2
which include a heavy atom like S, Se, or Te
Data Source
AI summary
A light emitting element of an embodiment includes a first electrode, a second electrode, and at least one functional layer disposed between the first electrode and the second electrode, wherein the at least one functional layer includes a first compound represented by Formula 1, and at least one compound selected from among a second compound represented by Formula 2, a third compound represented by Formula 3, and a fourth compound represented by Formula 4, thereby showing high efficiency and long-life characteristics.