OLED Phosphorescence-Sensitized Layer for Narrow-Spectrum Emission
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Solution Overview
Problem
Existing organic light-emitting diodes (OLEDs), particularly stacked-layer devices, suffer from low efficiency and short service life due to the limitations of phosphorescent materials with broad emission peaks and long-wavelength 3M LCT absorption.
Innovation Solution
Incorporating a phosphorescence sensitized layer with a host material, a phosphorescent sensitizer, and a narrow-spectrum fluorescent material with a full width at half maximum (FWHM) less than 45 nm to sensitize luminescence, thereby mitigating the broader FWHM issues of phosphorescent materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If phosphorescent materials are used in the light-emitting layer, then the device can achieve luminescence, but the full width at half maximum becomes broad and service life becomes short
Solution Approach 1:
The patent introduces a phosphorescent sensitizer as an intermediary substance between the host material and the fluorescent material. The phosphorescent sensitizer absorbs energy and transfers it to the fluorescent material, enabling the fluorescent material to emit light with narrow bandwidth. This mediator approach allows the system to achieve both efficient luminescence and narrow emission peaks without using conventional phosphorescent emitters that have broad peaks and short service life.
Solution Approach 2:
The patent changes the emission mechanism parameter by switching from direct phosphorescent emission to phosphorescence-sensitized fluorescent emission. By using a phosphorescent sensitizer with appropriate triplet energy level combined with a fluorescent material, the system transforms the emission characteristics to achieve narrow full width at half maximum (FWHM < 45 nm) while maintaining high efficiency and extending service life through the fluorescent material's inherent stability.
2Illumination intensity
If phosphorescent materials are used in the light-emitting layer, then the device can achieve luminescence, but the full width at half maximum becomes broad
Solution Approach 1:
The patent introduces a phosphorescent sensitizer as an intermediary substance between the host material and the fluorescent material. The phosphorescent sensitizer absorbs energy and transfers it to the fluorescent material, enabling the fluorescent material to emit light with narrow bandwidth. This mediator approach allows the system to achieve both efficient luminescence and narrow emission peaks without using conventional phosphorescent emitters that have broad peaks and short service life.
Solution Approach 2:
The patent changes the emission mechanism parameter by switching from direct phosphorescent emission to phosphorescence-sensitized fluorescent emission. By using a phosphorescent sensitizer with appropriate triplet energy level combined with a fluorescent material, the system transforms the emission characteristics to achieve narrow full width at half maximum (FWHM < 45 nm) while maintaining high efficiency and extending service life through the fluorescent material's inherent stability.
3Device complexity
If conventional phosphorescent materials are used, then the device structure is simple, but efficiency is low and service life is short
Solution Approach 1:
The patent employs a composite material system consisting of three components: host material, phosphorescent sensitizer, and fluorescent material. This composite light-emitting layer combines the advantages of different material types - the host material provides the matrix, the phosphorescent sensitizer enables efficient energy transfer with triplet state utilization, and the fluorescent material provides narrow emission peaks and high stability. The synergistic combination achieves high luminescence efficiency and extended service life while maintaining a relatively simple single-layer structure.
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
Improves the efficiency and service life of OLEDs by enhancing luminescence performance and stability, particularly in red light-emitting devices.
Implementation Method 1
the phosphorescent material is used to sensitize the narrow-spectrum fluorescent material for luminescence
Implementation Method 2
a narrow-spectrum fluorescent material, and the full width at half maximum of the narrow-spectrum fluorescent material is less than 45 nm
Data Source
AI summary
The present application provides an organic light-emitting diode and a display apparatus. The organic light-emitting diode comprises at least one light-emitting layer; the at least one light-emitting layer comprises at least one phosphorescence sensitized layer; the phosphorescence sensitized layer comprises a host material, a phosphorescent sensitizer, and a narrow-spectrum fluorescent material; and the full width at half maximum of the narrow-spectrum fluorescent material is less than 45 nm. The present application can improve the properties such as efficiency and service life of the organic light-emitting diode.