Condensed Cyclic OLED Compound for Delayed Fluorescence Efficiency
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Solution Overview
Problem
Current organic light-emitting devices face limitations in achieving high luminescent efficiency and long lifespan due to overlapping singlet and triplet energy levels, leading to inefficient light emission and reduced device performance.
Innovation Solution
A condensed cyclic compound represented by Formula 1 is introduced, featuring a specific molecular structure that allows for delayed fluorescence through thermally activated processes, reducing the energy gap between singlet and triplet states and enhancing charge transport capabilities, thereby improving light emission efficiency and device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional organic light-emitting devices are used, then device structure is simple, but luminescent efficiency is low due to overlapping singlet and triplet energy levels
Solution Approach 1:
The patent modifies the molecular structure parameters of the organic compound by introducing a condensed cyclic core with specific heteroatoms (X1, X2 from O, S, N, C, Si) and substituent groups (R1-R15). This structural parameter change creates a larger energy gap between singlet and triplet states, enabling efficient delayed fluorescence while maintaining device simplicity
Solution Approach 2:
The invention uses a composite molecular structure combining a condensed cyclic core (Formula 1) with various substituent groups (Formulas 2-4). This composite approach allows optimization of both energy levels and charge transport properties, achieving high luminescent efficiency through the synergistic effect of the core structure and substituents
2Duration of action of stationary object
If conventional organic compounds are used, then device manufacturing is easy, but lifespan is short due to triplet concentration-related deterioration
Solution Approach 1:
By changing the molecular parameters of the organic compound to include the condensed cyclic structure with specific heteroatom configurations, the patent reduces triplet concentration accumulation. This parameter modification suppresses triplet-triplet annihilation and other degradation pathways, extending device lifespan while maintaining ease of manufacturing
Solution Approach 2:
The patent converts the potentially harmful triplet excitons into beneficial delayed fluorescence emission through thermally activated processes. The condensed cyclic structure facilitates efficient reverse intersystem crossing, transforming triplet states that would normally cause deterioration into useful light emission, thereby extending device life
3Reliability
If conventional organic compounds are used, then charge transport is limited, but device complexity remains low
Solution Approach 1:
The patent employs composite molecular design where the condensed cyclic core (Formula 1) provides robust charge transport pathways through its extended π-conjugation and heteroatom arrangement. The core structure works synergistically with substituent groups (Formulas 2-4) to achieve high charge mobility without requiring complex device architectures
Solution Approach 2:
The invention applies local quality optimization by strategically placing electron-donating and electron-withdrawing groups at specific positions (R1-R15) on the condensed cyclic core. This localized functional differentiation enhances charge transport capability in specific regions of the molecule while maintaining overall structural simplicity and ease of synthesis
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 use of the condensed cyclic compound results in improved luminescent efficiency, reduced triplet concentration-related lifespan deterioration, and enhanced maximum quantum efficiency, leading to a low driving voltage and extended device lifespan.
Implementation Method 1
delayed fluorescence through thermally activated processes
Implementation Method 2
reducing the energy gap between singlet and triplet states
Implementation Method 3
Carriers, such as holes and electrons, may then recombine in the emission layer to produce excitons. These excitons transition from an excited state to a ground state, thereby generating light.
Data Source
AI summary
An organic light-emitting device includes: a first electrode; a second electrode facing the first electrode; an organic layer between the first electrode and the second electrode, the organic layer including an emission layer; and at least one condensed cyclic compound represented by Formula 1:wherein, in Formula 1, at least one selected from R1 to R15 is a group represented by Formula 2: