Organic Electroluminescent Layer Stack for Color Tone and Efficiency Stability
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Solution Overview
Problem
There is a need for organic electroluminescent elements that combine superior drive voltage characteristics, current efficiency characteristics, and precise control of color tone, with minimal efficiency change across a broad luminance range and after continuous operation.
Innovation Solution
An organic electroluminescent element comprising a positive electrode, a negative electrode, a light-emitting layer, a hole transport region, and an electron transport region, where the electron transport region contains a triazine compound and the hole transport region contains a radialene compound, enhancing the element's efficiency and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional organic electroluminescent elements are used, then drive voltage and current efficiency can be achieved, but color tone control precision and efficiency stability across luminance ranges deteriorate
Solution Approach 1:
The patent introduces a hole transport region with specific radialene compound (formula 3) having distinct properties from conventional materials. This localized functional region with optimized hole transport capability enables precise control of color tone while maintaining efficiency stability, resolving the contradiction between measurement precision and reliability.
Solution Approach 2:
The patent employs composite material strategy by combining radialene compound (formula 3) in the hole transport region with triazine compound (formula 2) in the electron transport region, and boron compound (formula 1) in the light-emitting layer. This composite approach achieves both superior drive voltage characteristics and efficiency stability across luminance ranges.
2Illumination intensity
If efficiency is optimized for high luminance, then high luminance performance improves, but low luminance efficiency and continuous operation stability deteriorate
Solution Approach 1:
The patent utilizes parameter changes by selecting specific compounds with optimized molecular structures (formulas 1, 2, and 3) that inherently provide stable efficiency across different operating conditions. The radialene compound (formula 3) and triazine compound (formula 2) are specifically designed to maintain consistent efficiency whether operating at high or low luminance, eliminating the need for complex adjustment mechanisms.
3Use of energy by stationary object
If drive voltage is reduced, then energy consumption decreases, but current efficiency and operational stability deteriorate
Solution Approach 1:
The patent achieves low drive voltage operation without sacrificing stability by using molecularly designed compounds (formulas 1, 2, and 3) that replicate the stable performance characteristics of conventional high-voltage materials at lower voltage operating conditions. The radialene compound (formula 3) and triazine compound (formula 2) are specifically engineered to maintain operational stability while enabling reduced drive 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 element achieves superior drive voltage and current efficiency with minimal efficiency change, enabling precise control of color tone for display and lighting applications.
Implementation Method 1
an electron transport region disposed between the light-emitting layer and the negative electrode, wherein the electron transport region contains a triazine compound represented by formula (2)
Implementation Method 2
a hole transport region disposed between the positive electrode and the light-emitting layer, wherein the organic electroluminescent element satisfies at least one or more of condition (i) or (ii) below. (ii) The hole transport region contains a radialene compound represented by formula (3)
Implementation Method 3
a light-emitting layer disposed between the positive electrode and the negative electrode
Data Source
AI summary
An organic electroluminescent element includes a positive electrode, a negative electrode opposite the positive electrode, a light-emitting layer disposed between the positive electrode and the negative electrode and a hole transport region disposed between the positive electrode and the light-emitting layer. The organic electroluminescent element includes an electron transport region disposed between the light-emitting layer and the negative electrode, the electron transport region contains a triazine compound represented by formula (2), and the organic electroluminescent element satisfies at least one or more of condition (i) or (ii) below.(i) The light-emitting layer contains a boron compound represented by formula (1).(ii) The hole transport region contains a radialene compound represented by formula (3).