Phosphorescent Polymer Light-Emitting Device for Efficiency and Durability
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Solution Overview
Problem
Existing organic light-emitting devices with a phosphorescent polymer compound tend to deteriorate easily and struggle to achieve high luminous efficiency due to the difficulty in combining energy levels of different functional properties within a single layer, often resulting in concentration quenching.
Innovation Solution
An organic light-emitting device is designed with a polymer compound that incorporates structural units from a hole transport or electron transport and phosphorescent polymerizable compound, along with a polymerizable compound capable of transporting oppositely charged carriers, utilizing specific substituents to enhance carrier transport and phosphorescent properties, thereby simplifying the selection of compounds and improving durability and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a phosphorescent low-molecular weight compound is copolymerized with polymerizable compounds having hole transport and electron transport properties to create a single-layer device, then the device complexity is reduced, but the durability deteriorates and the device tends to deteriorate more easily than multi-layered devices
Solution Approach 1:
The patent segments the functional units within the polymer compound by using copolymerization of different monomers with specific functions (phosphorescent, hole transport, electron transport). This allows each functional unit to be optimized separately while maintaining overall device simplicity, resolving the contradiction between device complexity reduction and durability maintenance.
2Device complexity
If polymerizable compounds are introduced into phosphorescent low-molecular weight compounds to create phosphorescent polymer compounds, then the device can be obtained by merely providing one layer, but it becomes difficult to attain high luminous efficiency due to strict energy level combination requirements
Solution Approach 1:
The patent changes the energy level parameters of the polymerizable compounds used in copolymerization to achieve optimal energy level matching. By carefully selecting and adjusting the energy levels of monomers with different functions, the patent enables efficient exciton generation on phosphorescent structural units while maintaining the single-layer structure, thus resolving the contradiction between device simplicity and luminous efficiency.
3Use of energy by moving object
If a polymer compound containing structural units with phosphorescent property in high concentration is used to improve luminous efficiency, then the phosphorescent property is enhanced, but concentration quenching takes place and high luminous efficiency is not attained
Solution Approach 1:
The patent applies local quality by creating specific microenvironments around phosphorescent structural units through the copolymerization with hole transport and electron transport monomers. This local structural optimization prevents concentration quenching by ensuring proper spacing and energy transfer pathways, allowing high phosphorescent unit concentration without the harmful quenching effect, thus achieving high luminous efficiency.
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 solution results in an organic light-emitting device with high luminous efficiency and excellent durability by using fewer kinds of compounds and easier energy level adjustments, suppressing concentration quenching and achieving better exciton generation.
Implementation Method 1
a polymerizable compound (a1) having one carrier transport property either of a hole transport property or an electron transport property and a phosphorescent property
Implementation Method 2
the polymerizable compound (a1) having one carrier transport property either of a hole transport property or an electron transport property
Implementation Method 3
a polymerizable compound (b) having the other carrier transport property
Implementation Method 4
it has the functions of the hole transport property and the electron transport property as well as the phosphorescent property within a single compound
Data Source
AI summary
Disclosed is an organic light-emitting device which contains one or more organic layers sandwiched between an anode and a cathode, wherein at least one of the organic layers is a light-emitting layer including a polymer compound (I), the polymer compound (I) containing structural units derived from a hole transport or electron transport and phosphorescent polymerizable compound (a1) and structural units derived from a polymerizable compound (b) capable of transporting an oppositely charged carrier, the polymerizable compound (a1) being selected from formulae (E1-1) to (E1-39) as defined herein.