Dibenzo[fg,op]tetracene Hosts for OLED Efficiency
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Solution Overview
Problem
Current organic light-emitting devices (OLEDs) face challenges in achieving low-voltage, high-efficiency, and high-stability performance, particularly in phosphorescent emitters, where host materials with high triplet energy are needed to optimize device performance.
Innovation Solution
Development of novel compounds containing dibenzo[fg,op]tetracene and larger all-benzenoid moieties as hosts for phosphorescent emitters, which can be used in OLEDs as emitters, hosts, or charge transport materials, enabling low-voltage and high-efficiency operation through their high triplet energy and deep LUMO levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional host materials are used in phosphorescent OLEDs, then device fabrication is simpler, but device efficiency and stability are insufficient
Solution Approach 1:
The patent changes the chemical structure parameters of host materials by incorporating dibenzo[fg,op]tetracene and larger all-benzenoid moieties, which possess high triplet energy levels. This structural parameter change enables the host materials to effectively triplet excitons and transfer them to phosphorescent emitters, thereby improving device efficiency without excessive complexity
Solution Approach 2:
The patent employs composite host materials that combine dibenzo[fg,op]tetracene or larger all-benzenoid cores with various functional groups and substituents. These composite structures integrate high triplet energy with appropriate HOMO/LUMO levels, enabling simultaneous achievement of high efficiency, low operating voltage, and improved stability
2Reliability
If host materials with high triplet energy are used, then phosphorescent emitter performance is improved, but material synthesis becomes more difficult
Solution Approach 1:
The patent segments the host material structure into a rigid all-benzenoid core (dibenzo[fg,op]tetracene or larger) and peripheral functional groups. This segmentation allows the core to provide high triplet energy for stability while peripheral groups can be optimized for synthesis ease, charge transport, and device processing
Solution Approach 2:
The patent extracts the essential high triplet energy function to the all-benzenoid core structure, separating it from other functional requirements. This extraction allows the core to be optimized for stability while other parts of the molecule can be optimized for ease of manufacture and device performance
3Use of energy by moving object
If deep LUMO level materials are used, then operating voltage is reduced, but electron transport capability may be compromised
Solution Approach 1:
The patent applies local quality by creating regions of different electronic properties within the host material structure. The all-benzenoid core provides deep LUMO levels for low operating voltage, while peripheral functional groups with electron-transporting moieties are strategically placed to ensure adequate electron mobility, thus resolving the contradiction locally
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 these compounds results in OLEDs with improved efficiency and stability, allowing for low operating voltages and enhanced performance in both single and multiple color devices, with the ability to be vapor-evaporated or solution-processed.
Implementation Method 1
OLEDs make use of thin organic films that emit light when voltage is applied across the device
Implementation Method 2
phosphorescent organic light-emitting device comprising: an anode, a cathode, and an organic layer, disposed between the anode and the cathode, comprising a compound containing an all-benzenoid group having at least 24 carbon atoms
Data Source
AI summary
The present disclosure provides novel compounds containing dibenzo[fg,op]tetracene and larger all-benzenoid moiety that can be used as hosts for phosphorescent emitters providing low-voltage, high-efficiency and high-stability devices.