Quantum Dot OLED Emission Layer for Color and Lifespan Balance
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Solution Overview
Problem
Existing OLED displays face challenges in achieving optimal color characteristics and longevity due to limitations in quantum dot (QD) color conversion elements, particularly in blue and white-OLED substrates.
Innovation Solution
A display apparatus incorporating a substrate with blue light-emitting units and a color control portion featuring quantum dots for green light conversion, along with specific dopants and emission layers designed to meet certain energy and emission criteria, enhancing color control and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If quantum dot color conversion elements are used in OLED displays, then color characteristics are improved, but lifespan is reduced
Solution Approach 1:
The patent changes the energy level parameters of the dopants to resolve the contradiction. Specifically, it selects a first dopant with a lowest triplet excitation energy of 2.3-2.7 eV and a second dopant with a lowest triplet excitation energy of 2.0-2.4 eV, ensuring proper energy level alignment for efficient energy transfer while maintaining stability and lifespan
Solution Approach 2:
The patent uses a composite emission layer containing both a first dopant (e.g., Ir(III) or Pt(II) complex) and a second dopant (e.g., TCTA or TAPC) together with a host material. This composite structure enables synergistic effects where the first dopant absorbs blue light and transfers energy to the second dopant, which then emits green light, achieving both improved color characteristics and extended lifespan
2Productivity
If quantum dot color conversion elements are used, then color conversion efficiency is improved, but manufacturing complexity increases
Solution Approach 1:
The patent merges multiple functions into a single emission layer by combining the host material, first dopant (for blue light absorption), and second dopant (for green light emission) into one integrated layer. This eliminates the need for separate quantum dot layers and simplifies the manufacturing process while maintaining high color conversion efficiency
Solution Approach 2:
The patent optimizes the concentration parameters of the dopants to achieve efficient color conversion. The first dopant is used at 0.01-5 wt% and the second dopant at 0.1-10 wt%, with specific weight ratios between 0.1-10, ensuring high color conversion efficiency while using simple solution processing techniques that reduce manufacturing 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 a display apparatus with improved color characteristics and extended lifespan by optimizing the emission spectrum and absorption properties of quantum dots, ensuring efficient light conversion and durability.
Implementation Method 1
the first dopant has a lowest triplet excitation energy and a lowest singlet excitation energy, the second dopant has a lowest triplet excitation energy and a lowest singlet excitation energy
Implementation Method 2
the emission layer exhibits an emission spectrum including a first emission peak and a second emission peak
Implementation Method 3
the first color control element includes a first quantum dot for green light conversion
Implementation Method 4
the first color control element exhibits an absorption spectrum including a first absorption peak and a first absorption valley
Data Source
AI summary
A display apparatus, including a substrate including at least one blue light-emitting unit, and a color control portion provided on the substrate and configured to control a color of a light generated at the substrate, wherein the color control portion includes a first color control element, wherein the first color control element includes a first quantum dot for green light conversion, and the at least one blue light-emitting unit of the substrate includes an emission layer, wherein the emission layer includes a host, a first dopant, and a second dopant, and wherein the display apparatus further satisfies conditions as defined herein.