Blue OLED Emitter Layer with Phosphorescent Scavenger
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Solution Overview
Problem
Organic light-emitting diodes (OLEDs) with blue or violet emission have shorter lifetimes and lower quantum efficiency compared to those emitting in the green, yellow, orange, or red spectral range, limiting their application in display and lighting.
Innovation Solution
A radiation-emitting device with an emitter layer containing a fluorescent emitter and a phosphorescent exciton scavenger, where the exciton scavenger enhances energy transfer to the fluorescent emitter, improving quantum efficiency and service life by transferring triplet excitons to the singlet state of the fluorescent emitter, thereby increasing radiative decay and charge carrier transport.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If a fluorescent emitter is used in the violet or blue spectral range, then the service life is extended compared to phosphorescent emitters, but the quantum efficiency is significantly reduced
Solution Approach 1:
The invention combines a fluorescent emitter and a phosphorescent emitter in a single emitter layer, creating a hybrid system that merges the long lifetime of fluorescent emitters with the high quantum efficiency of phosphorescent emitters. The fluorescent emitter provides the operational longevity while the phosphorescent emitter enhances light output efficiency, and both work synergistically within the same device structure.
Solution Approach 2:
The emitter layer uses a composite material system comprising both fluorescent and phosphorescent emitting substances dispersed in a matrix material. This composite approach allows the device to simultaneously exhibit the beneficial properties of both emitter types: the extended lifetime characteristic of fluorescent emitters and the high quantum efficiency characteristic of phosphorescent emitters.
2Use of energy by moving object
If a phosphorescent emitter is used in the violet or blue spectral range, then the quantum efficiency is increased, but the service life is significantly reduced
Solution Approach 1:
The invention combines a fluorescent emitter and a phosphorescent emitter in a single emitter layer, creating a hybrid system that merges the long lifetime of fluorescent emitters with the high quantum efficiency of phosphorescent emitters. The fluorescent emitter provides the operational longevity while the phosphorescent emitter enhances light output efficiency, and both work synergistically within the same device structure.
Solution Approach 2:
The emitter layer uses a composite material system comprising both fluorescent and phosphorescent emitting substances dispersed in a matrix material. This composite approach allows the device to simultaneously exhibit the beneficial properties of both emitter types: the extended lifetime characteristic of fluorescent emitters and the high quantum efficiency characteristic of phosphorescent emitters.
3Use of energy by moving object
If the proportion of phosphorescent exciton scavenger is increased, then the quantum efficiency is improved, but the device complexity increases
Solution Approach 1:
The invention optimizes the concentration parameters of the emitting substances within specific ranges (fluorescent emitter: 0.1-5% by weight, phosphorescent emitter: 1-30% by weight) to achieve high quantum efficiency while maintaining manageable device complexity. By carefully controlling these compositional parameters, the system achieves optimal performance without requiring overly complex device structures.
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 significantly increased quantum efficiency, improved charge carrier balance, lower operating voltage, and extended service life, with lifetimes exceeding 10,000 hours at high luminance, while maintaining the color impression of the emitted light.
Implementation Method 1
the exciton scavenger enhances energy transfer to the fluorescent emitter, improving quantum efficiency and service life by transferring triplet excitons to the singlet state of the fluorescent emitter
Implementation Method 2
which includes a phosphorescent exciton scavenger in addition to the matrix material and the fluorescent emitter
Implementation Method 3
a fluorescent radiation-emitting emitter (which emits in the violet or blue spectral range)
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to a radiation-emitting device comprising a substrate, a first and a second electrode, and an emitter layer arranged between the first and the second electrode that emits light in the violet or blue spectral range. The emitter layer contains a matrix material and (relative to the matrix material) 0.1 - 5 wt % of a fluorescent radiation-emitting emitter and 1-30 wt % of a phosphorescent exciton trap. The maximum emission of the fluorescent emitter and the maximum emission of the phosphorescent exciton trap lie within the blue, violet, or ultraviolet spectral range.