Mixed Host Compound for Organic Electronic Element Charge Balance
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Solution Overview
Problem
The development of stable and efficient host materials for organic electric elements, particularly for phosphorescent emitting layers, is hindered by the challenge of controlling charge balance and optimizing energy transfer from host to dopant materials.
Innovation Solution
A compound is used as a phosphorescent host material in organic electric elements, comprising a mixture of a first host compound and a second host compound. This mixture reduces the energy barrier between the emitting layer and adjacent layers, maximizing charge balance and improving efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single host material is used in the emitting layer, then the device structure is simple, but charge balance cannot be effectively controlled and energy transfer efficiency is insufficient
Solution Approach 1:
The patent employs a composite host material system comprising a first host material and a second host material in the emitting layer. The first host material forms the primary matrix while the second host material is introduced in specific amounts (1-50 wt%) to modify charge transport properties and energy transfer characteristics. This composite approach enables simultaneous optimization of charge balance and energy transfer efficiency without significantly complicating the overall device structure.
Solution Approach 2:
The patent systematically varies the composition ratio, molecular weight, and chemical structure parameters of the host materials to optimize device performance. By adjusting the weight ratio of first to second host material (1:49 to 9:1), and selecting host materials with specific HOMO/LUMO energy levels and glass transition temperatures, the invention achieves precise control over charge balance and energy transfer while maintaining structural simplicity.
2Productivity
If the HOMO level of the host material is not optimized, then material selection is simple, but hole injection efficiency and charge balance are poor
Solution Approach 1:
The patent establishes specific parameter ranges for host materials to optimize hole injection: HOMO level between -5.0 to -6.0 eV, glass transition temperature (Tg) between 80-150°C, and specific molecular weight ranges. These parameter specifications enable systematic selection of host materials that achieve high hole injection efficiency while maintaining manageable material selection complexity through defined criteria.
Solution Approach 2:
The second host material acts as an intermediary component that facilitates optimal hole injection from the hole transport layer into the emitting layer. By selecting a second host material with appropriate energy level alignment (HOMO within 0.2-1.0 eV of the hole transport layer), the invention enables efficient charge transfer while the first host material maintains the primary structural framework.
3Productivity
If the energy transfer method from host to dopant is not optimized, then material development is straightforward, but luminous efficiency and lifespan are insufficient
Solution Approach 1:
The patent optimizes energy transfer by controlling the triplet energy level (ET) of the host material to be higher than that of the phosphorescent dopant, ensuring efficient reverse energy transfer. The glass transition temperature (Tg) is maintained between 80-150°C to ensure adequate molecular mobility for energy transfer while preventing material degradation. These parameter optimizations achieve high luminous efficiency without requiring complex energy transfer mechanisms.
Solution Approach 2:
The patent employs conventional phosphorescent dopants with established energy levels and well-understood photophysics, avoiding the need for exotic or newly developed dopant materials. This approach enables efficient energy transfer through proven mechanisms while keeping material development and device fabrication relatively straightforward.
4Reliability
If the LUMO and HOMO levels of the host material are not properly aligned, then material selection is simple, but electron and hole injection efficiency and charge balance are poor
Solution Approach 1:
The second host material serves as an energy level intermediary that bridges the hole transport layer and the first host material. By selecting a second host with HOMO level within 0.2-1.0 eV of the hole transport layer, the patent enables gradual energy level transition, facilitating efficient hole injection while the first host material maintains its primary structural role. This intermediary approach simplifies the overall energy level matching requirement.
Solution Approach 2:
The patent defines specific energy level parameter ranges for both host materials: first host HOMO between -5.0 to -6.0 eV and LUMO between -2.0 to -3.0 eV, with the second host providing complementary energy level alignment. These parameter specifications enable systematic material selection that achieves optimal charge balance without requiring complex multi-parameter optimization.
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 mixed host compound achieves high luminous efficiency, low driving voltage, and significantly improved lifespan of organic electric elements, enhancing the overall performance of the devices.
Implementation Method 1
An organic electric element using an organic light emitting phenomenon... in a phosphorescent organic electric element using a phosphorescent dopant material
Implementation Method 2
there are various factors that affect the efficiency and lifespan depending on how energy is transferred from the host material to the dopant material
Implementation Method 3
organic light emitting phenomenon refers to a phenomenon that converts electric energy into light energy by using an organic material
Data Source
AI summary
Provided is a novel mixture capable of improving luminous efficiency, stability, and lifespan of an element, an organic electric element using the same, and an electronic device therefor.