Light-Emitting Device With Exciplex Hosts And Quantum Dots
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Solution Overview
Problem
Current light-emitting devices face limitations in achieving high efficiency and color purity due to the inherent limitations of single-emission layer structures, which restrict their luminescence efficiency and color reproducibility.
Innovation Solution
A light-emitting device is designed with multiple emitting units and charge generation units, where each emitting unit consists of a hole transport region, an emission layer, and an electron transport region, with specific host and dopant combinations forming exciplexes to enhance luminescence efficiency, and quantum dots are used to improve color purity and viewing angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a single emission layer structure is used, then the device structure is simple, but the luminescence efficiency and color purity are limited
Solution Approach 1:
The emission layer is divided into multiple distinct emission layers (first emission layer with first host and first dopant, second emission layer with second host and second dopant) that can be independently optimized for different wavelengths and efficiency characteristics, resolving the contradiction between structural simplicity and luminescence efficiency
Solution Approach 2:
The patent employs composite material systems where each emission layer combines specific host-guest material pairs (first host-first dopant, second host-second dopant) to achieve synergistic effects that enhance overall luminescence efficiency and color purity beyond what single materials can provide
2Ease of manufacture
If a single emission layer structure is used, then the device structure is simple, but the color purity and reproducibility are limited
Solution Approach 1:
The emission spectrum is segmented across multiple emission layers, with each layer contributing to specific color components. This segmentation enables precise control over the overall color output and improves color purity by eliminating spectral overlap issues present in single-layer structures
Solution Approach 2:
Each emission layer is designed with locally optimized material compositions (specific host-guest pairs) tailored to emit at particular wavelengths with high purity, allowing different regions of the device to contribute different color qualities that combine to achieve superior overall color reproduction
3Loss of energy
If multiple emission layers with exciplex formations and quantum dots are used, then the luminescence efficiency and color purity are improved, but the device complexity increases
Solution Approach 1:
The complex emission structure is segmented into modular emission layers, each with a standardized configuration of host-guest-exciplex-quantum dot components. This modular segmentation makes the complex structure more manageable and manufacturable while maintaining high luminescence efficiency
Solution Approach 2:
Each emission layer is designed as a multi-functional unit that simultaneously performs exciplex formation for efficient energy transfer, quantum dot incorporation for color purification, and host-guest complexation for stabilized emission. This universality reduces overall device complexity by consolidating multiple functions into integrated layers
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 device achieves improved luminescence efficiency and color purity by utilizing multiple emission layers with exciplex formations and quantum dots, leading to enhanced internal quantum efficiency and reduced chromaticity changes with current density.
Implementation Method 1
the first host and the second host form a first exciplex, the third host and the fourth host form a second exciplex
Implementation Method 2
the first dopant is a delayed fluorescence dopant, and the second dopant is a phosphorescent dopant
Implementation Method 3
the second dopant is a phosphorescent dopant
Implementation Method 4
An electronic apparatus may include the light-emitting device. The electronic apparatus may include a quantum dot or an optical member including the quantum dot
Data Source
AI summary
A light-emitting device including: m emitting units located between a first electrode and a second electrode; and m−1 charge generation units, each located between two neighboring emitting units among the m emitting units and including an n-type charge generation layer and a p-type charge generation layer. The m emitting units may each include an emission layer, at least one of the m emission layers comprises a first emission layer and a second emission layer that are in contact with each other, the first emission layer includes a first host, a second host, and a first dopant, the second emission layer includes a third host, a fourth host, and a second dopant, the first host and the second host form a first exciplex, the third host and the fourth host form a second exciplex, and the first dopant is a delayed fluorescence dopant, and the second dopant is a phosphorescent dopant.