OLED Organic Material Composition for Low-Voltage Charge Balance
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Solution Overview
Problem
Existing organic light-emitting diodes (OLEDs) face challenges in achieving low operational voltages, high brightness, and balanced hole and electron injection/transport to enhance efficiency and lifetime.
Innovation Solution
The use of a specific organic material with a defined molecular structure, including aryl and heteroaryl groups, in the emission layer and electron transport layers, along with n-dopants like lithium quinolinolate complexes, to improve charge injection and transport efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional organic materials are used in OLEDs, then device structure is simple, but operational voltage is high and efficiency is low
Solution Approach 1:
The patent applies parameter changes by modifying the molecular structure of organic materials through specific chemical groups and substituents (R1-R6, X, Y, Z parameters) to optimize electronic properties. The complex molecular formulas with varied aromatic rings, heteroatoms, and functional groups enable tuning of HOMO/LUMO levels, charge mobility, and recombination efficiency, thereby reducing operational voltage and improving EQE despite increased structural complexity
Solution Approach 2:
The patent employs composite materials by combining multiple organic compounds with different functions in the OLED structure. The electron transport layer uses compounds of formula (I) with specific aromatic and heteroaryl groups, while the emission layer uses separate emitter and host materials. This composite approach balances electron and hole transport, reduces operational voltage, and enhances overall device efficiency
2Productivity
If conventional organic materials are used in OLEDs, then material selection is simple, but external quantum efficiency is low
Solution Approach 1:
The patent improves external quantum efficiency by changing molecular parameters including aromatic ring systems, heteroatom types and positions, and substituent groups. These structural modifications optimize charge carrier mobility, exciton generation, and radiative recombination rates, achieving EQE >25% through precise molecular design rather than simple material selection
Solution Approach 2:
The patent introduces intermediary substances including dopants (e.g., lithium quinolinolate complexes), hole blocking agents, and electron transport compounds that mediate between electrodes and emission layers. These intermediaries facilitate balanced charge injection, prevent charge accumulation, and enhance recombination efficiency, thereby improving EQE despite adding complexity to the device architecture
3Duration of action of stationary object
If conventional organic materials are used in OLEDs, then device structure is simple, but lifetime is short
Solution Approach 1:
The patent extends device lifetime by using composite material structures with specialized functional layers. The electron transport layer contains compounds of formula (I) with specific aromatic and heteroaryl groups that provide stable electron transport, while separate hole blocking and emission layers prevent degradation. This multi-layer composite structure protects against operational stress and extends lifetime despite increased structural complexity
Solution Approach 2:
The patent employs intermediary layers including hole blocking agents and electron transport compounds that act as protective barriers between electrodes and emission materials. These intermediaries prevent charge accumulation, reduce electrochemical degradation, and stabilize operational conditions, thereby extending device lifetime through added structural complexity
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 approach results in OLEDs with enhanced external quantum efficiency, lower operating voltage, and extended lifespan.
Implementation Method 1
One of well-established approaches for achieving low operational voltages and high current densities/luminances is electrical p- and/or n-doping in charge injection/charge transport layers, and especially redox doping which generates doped layers with high charge carrier concentrations
Implementation Method 2
The holes and electrons recombine in the EML to generate excitons. When the excitons drop from an excited state to a ground state, light is emitted
Data Source
AI summary
The present invention relates to an organic material and to an electronic device comprising the organic material, particularly to an electroluminescent device, particularly to an organic light emitting diode (OLED), wherein the semiconducting material comprises a multiple-substituted phenyl moiety, an aryl moiety with at least two fused rings, a polar moiety and optional linkers between these moieties.