Triphenylenyl Host Material for Delayed Fluorescent OLEDs
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Solution Overview
Problem
Existing organic electroluminescence devices using delayed fluorescent materials have short device lifetimes and low light emission efficiency due to the lack of suitable host materials that match the unique characteristics of delayed fluorescent materials.
Innovation Solution
A compound with a structure featuring plural triphenylenyl groups bonded via a carbonyl group or aromatic hydrocarbon group is used as a host material, enhancing device lifetime and light emission efficiency while reducing driving voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If carbazole-type host materials (mCP, CBP) are used with delayed fluorescent materials, then the device can be manufactured with existing materials, but the device lifetime is only 50 hours or so and is short
Solution Approach 1:
The patent changes the chemical structure parameters of the host material from carbazole-type to triphenylenyl-type compounds. This structural parameter change fundamentally alters the material's interaction with delayed fluorescent materials, enabling much longer device lifetimes (exceeding 500 hours) while maintaining manufacturability.
Solution Approach 2:
The patent creates a composite light-emitting layer combining triphenylenyl-type host materials with delayed fluorescent materials. This composite material system achieves synergistic effects where the host material's unique structure enables efficient energy transfer and long device operation, solving both the lifetime and reliability issues.
2Productivity
If conventional host materials are used with delayed fluorescent materials, then the device structure is simple and easy to manufacture, but the light emission efficiency is low and device performance is poor
Solution Approach 1:
The patent modifies the structural parameters of host materials by introducing triphenylenyl cores with specific substituents (carboxyl, carbonyl, hydroxyl groups). These parameter changes enable the material to achieve high light emission efficiency with delayed fluorescent materials while maintaining reasonable structural complexity for synthesis.
Solution Approach 2:
The patent introduces specific functional groups (carboxyl, carbonyl, hydroxyl) at specific positions on the triphenylenyl core structure. These local quality modifications create optimal interaction sites with delayed fluorescent materials, enhancing energy transfer efficiency and overall device performance without requiring complete structural redesign.
3Use of energy by moving object
If existing host materials are used, then the device can operate at standard voltages, but the driving voltage is too high and energy efficiency is low
Solution Approach 1:
The patent changes the electronic parameters of the host material through triphenylenyl-based structure design, which modifies the energy levels and charge transport properties. This enables the device to operate at lower driving voltages while improving energy efficiency, as the new host materials facilitate better charge injection and transport.
Solution Approach 2:
The patent replaces the conventional charge transport mechanism (relying on carbazole-based materials) with a new mechanism based on triphenylenyl-type materials that have superior electron mobility and energy level alignment. This substitution enables more efficient energy utilization and reduced operating voltage.
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 compound significantly prolongs device lifetime and achieves high light emission efficiency with low driving voltage, outperforming traditional carbazole-type host materials in organic electroluminescence devices.
Implementation Method 1
a delayed fluorescent material is a light-emitting material that radiates fluorescence directly from the excited singlet state and radiates fluorescence (delayed fluorescence) also from the excited singlet state formed through reverse intersystem crossing from the excited triplet state
Implementation Method 2
by using a compound having a structure where plural triphenylenyl groups bond via a carbonyl group or an aromatic hydrocarbon group as a host material for delayed fluorescent materials, not only the device lifetime can be more greatly prolonged but also high efficiency and low-voltage driving can be expected
Data Source
AI summary
A compound represented by (Tr)n-Z is useful as a host material for delayed fluorescent materials. Tr represents a substituted or unsubstituted triphenylenyl group, and plural Tr's existing in the general formula (1) may be the same as or different from each other. Z represents a carbonyl group or a substituted or unsubstituted, n-valent aromatic hydrocarbon group. n represents an integer of 2 to 6, but when Z is a carbonyl group, n is 2.