Dual Dopant Organic Light Emitting Device Lifespan Efficiency
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Solution Overview
Problem
Existing organic light-emitting devices with a 2-stack structure face challenges in achieving desired color quality while improving efficiency and lifespan, as the choice of dopants is limited, with short-wavelength dopants enhancing color gamut but shortening lifespan and long-wavelength dopants improving lifespan but reducing efficiency.
Innovation Solution
An organic light-emitting device with a 2-stack structure employs a first organic emission layer with a higher concentration of a long-wavelength dopant and a second organic emission layer with a higher concentration of a short-wavelength dopant, where the maximum luminescence wavelength of the first dopant is larger than that of the second dopant, optimizing dopant concentrations to enhance both efficiency and lifespan.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a short-wavelength dopant is used in the organic emission layer, then color gamut is enhanced, but lifespan is shortened
Solution Approach 1:
The organic emission layer is divided into multiple sub-layers, each containing dopants with different wavelength characteristics. This segmentation allows the device to achieve broad color gamut while distributing degradation stress across multiple layers, thereby extending overall lifespan.
Solution Approach 2:
Different regions of the emission layer are assigned different dopant concentrations and wavelength characteristics optimized for their specific function. Short-wavelength dopants are used in regions where color gamut is prioritized, while long-wavelength dopants are used in regions where stability and lifespan are more critical.
2Duration of action of stationary object
If a long-wavelength dopant is used in the organic emission layer, then lifespan is improved, but efficiency is reduced
Solution Approach 1:
The emission layer is segmented into multiple functional zones with different dopant compositions. Long-wavelength dopants are concentrated in sub-layers where stability is critical, while short-wavelength dopants are placed in sub-layers where efficiency and color gamut are prioritized, achieving both longevity and performance.
Solution Approach 2:
The organic emission layer employs a composite structure with multiple dopant types distributed across different sub-layers. This composite approach combines the lifespan benefits of long-wavelength dopants with the efficiency advantages of short-wavelength dopants, creating a synergistic effect that exceeds the performance of single-dopant systems.
3Manufacturing precision
If the number of pixels per area is increased for high-definition displays, then display quality is improved, but electric current per area is limited
Solution Approach 1:
The patent optimizes dopant concentration parameters across different emission sub-layers to enhance luminous efficiency. By carefully controlling dopant amounts and distribution, the device achieves higher brightness output per unit current, enabling high-definition displays with increased pixel density without proportionally increasing power consumption.
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
This approach allows for achieving a desired color quality while improving the efficiency and lifespan of the organic light-emitting device, with the first dopant prioritizing lifespan in the first emission layer and the second dopant prioritizing efficiency in the second emission layer, demonstrating improved performance over existing solutions.
Implementation Method 1
An OLED apparatus utilizes an organic light-emitting device in which electrons from a cathode and holes from an anode are injected into an emission layer, and the electrons and holes recombine to form excitons, such that light is emitted when the excitons change from an excited state to the ground state.
Implementation Method 2
a first organic emission layer disposed between the first electrode and the second electrode and comprising a first dopant; and a second organic emission layer disposed between the first electrode and the second electrode and comprising a second dopant, wherein a maximum luminescence wavelength of the first dopant is larger than a maximum luminescence wavelength of the second dopant
Data Source
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AI summary
An organic light-emitting device (1000) includes a first electrode (110) and a second electrode (200), a first organic emission layer (140-142) disposed between the first electrode (110) and the second electrode (200) and comprising a first dopant, and a second organic emission layer (180-182) disposed between the first electrode (110) and the second electrode (200) and comprising a second dopant. The maximum luminescence wavelength of the first dopant may be larger than the maximum luminescence wavelength of the second dopant. The difference between the maximum luminescence wavelength of the first dopant and the maximum luminescence wavelength of the second dopant is 10 nm or less.