Heterocyclic Compound for OLED Delayed Fluorescence
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Solution Overview
Problem
Current organic light-emitting devices (OLEDs) face challenges in achieving high efficiency and long lifespan due to limitations in luminescent material characteristics, such as narrow full width at half maximum (FWHM), high emission luminance, short emission wavelength, and short exciton lifespan, which are not adequately addressed by existing compounds.
Innovation Solution
Incorporation of a heterocyclic compound represented by Formula 1, which exhibits delayed fluorescence characteristics due to internal charge transfer, serving as an electron donor linked to an electron acceptor with steric hindrance, enhancing luminescent material properties and acting as a host for blue light-emitting materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If existing luminescent materials are used in OLEDs, then device structure and operation can be maintained, but efficiency and lifespan are limited due to narrow FWHM, high emission luminance, short emission wavelength, and short exciton lifespan
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of luminescent materials to achieve desired optical properties. Specifically, it uses compounds with controlled full width at half maximum (FWHM) between 50-150 nm, optimized emission wavelengths in the blue region (450-480 nm), and adjusted exciton lifetimes to improve both efficiency and device stability without sacrificing lifespan
Solution Approach 2:
The patent employs composite materials by combining host materials with guest luminescent compounds in specific ratios. The host material provides structural support and charge transport, while the guest compound (e.g., iridium complexes or organic dyes) provides luminescence. This composite approach allows optimization of both efficiency and lifespan by selecting compatible material pairs with matched energy levels and stable interactions
2Illumination intensity
If luminescent materials with narrow FWHM and short emission wavelength are used, then high luminance efficiency is achieved, but exciton lifespan becomes too short limiting device performance
Solution Approach 1:
The patent utilizes phase transitions in the form of delayed fluorescence mechanisms where excitons transition between singlet and triplet states. By incorporating materials that facilitate reverse intersystem crossing (RISC), the patent extends the effective lifetime of excitons while maintaining high luminance through delayed fluorescence emission, resolving the contradiction between short wavelength/high luminance and short exciton lifespan
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 heterocyclic compound improves OLED performance by reducing driving voltage, increasing efficiency, and extending lifespan with excellent luminescent characteristics, including a narrow FWHM, high luminance, and short exciton lifespan, making it suitable for use in emission layers or as a host material.
Implementation Method 1
exhibits delayed fluorescence characteristics due to internal charge transfer
Implementation Method 2
exhibits delayed fluorescence characteristics due to internal charge transfer
Implementation Method 3
Carriers, such as holes and electrons, recombine in the emission layer to produce excitons. Then, the excitons are transitioned from an excited state to a ground state, thereby generating light
Data Source
AI summary
An organic light-emitting device and a heterocyclic compound, the device including a first electrode; a second electrode facing the first electrode; and an organic layer between the first electrode and the second electrode and including an emission layer, wherein the organic layer includes a heterocyclic compound represented by Formula 1: