Polymer Light-Emitting Layer for OLED Brightness and Durability
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Solution Overview
Problem
Existing organic light-emitting devices face challenges in achieving high brightness and long life while maintaining high luminous efficiency, particularly due to issues with film thickness uniformity and durability when using low molecular weight compounds in multilayer structures, and the limitations of phosphorescent polymers in terms of maximum brightness and durability.
Innovation Solution
The development of an organic light-emitting device that incorporates a polymer compound with a structural unit derived from a specific polymerizable compound having hole transport properties, which includes a phosphorescent polymerizable compound and an electron transport polymerizable compound, forming a light-emitting layer that can be coated using a simple method, enabling high brightness and long life with high luminous efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a phosphorescent polymer obtained by copolymerizing a phosphorescent polymerizable compound and a charge transport polymerizable compound is used, then the light-emitting layer can be formed by a coating method such as spin coating, but there is room for improvement with respect to the maximum attainable brightness and the durability
Solution Approach 1:
The patent uses a composite polymer material comprising both a phosphorescent polymerizable compound and a charge transport polymerizable compound in the light-emitting layer. This composite structure enables the layer to be formed by coating methods while maintaining high durability and maximum brightness, resolving the contradiction between ease of manufacture and reliability.
2Ease of manufacture
If a low molecular weight compound such as a triphenylamine derivative is used in the hole transport layer, then vacuum deposition method is generally employed, but the film thickness of the layer is likely to be uneven and devices with large areas are difficult to produce
Solution Approach 1:
The patent replaces the mechanical vacuum deposition method with a coating method for forming the light-emitting layer. This substitution eliminates the need for complex vacuum equipment, ensures uniform film thickness, and enables production of large-area devices, resolving the contradiction between ease of manufacture and device 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
The solution results in an organic light-emitting device with enhanced brightness, extended life, and improved luminous efficiency, overcoming the limitations of previous technologies by using a polymer-based light-emitting layer that can be easily formed and applied to large areas.
Implementation Method 1
a polymer compound comprising a structural unit derived from a polymerizable compound (A) represented by the following general formula (1) having a hole transport property
Implementation Method 2
a phosphorescent compound in the light-emitting layer emits light
Data Source
AI summary
An organic light-emitting device in which at least one organic layer including a light-emitting layer is sandwiched between an anode and a cathode and a phosphorescent compound in the light-emitting layer emits light. The light-emitting layer contains a polymer compound including a structural unit derived from a polymerizable compound (A) represented by the following general formula (1) where R1-R24 are as defined herein: