Phosphorescent OLED Microcapsule for Self-Quenching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Phosphorescent OLED devices suffer from self-quenching of molecular excitation, leading to reduced brightness and are susceptible to moisture and oxygen, causing black spots and shortening their lifespan.
Innovation Solution
A light emitting microcapsule with a phosphorescent core material encapsulated in a wall material that prevents molecular aggregation and permeation of moisture and oxygen, using materials like Ir complexes and natural or synthetic polymers with high transmittance and low permeability, and a method of microencapsulation such as coacervation to form microcapsules with sizes ranging from 0.5-200 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If phosphorescent material is used in OLED devices, then internal quantum efficiency is improved, but self-quenching occurs leading to reduced brightness
Solution Approach 1:
The phosphorescent material is divided into discrete microcapsules (0.5-200 μm) containing individual phosphorescent particles (0.1-20 nm). This segmentation prevents molecular aggregation and self-quenching by isolating phosphorescent molecules within separate capsules, thereby maintaining high internal quantum efficiency while preserving brightness at high current densities
Solution Approach 2:
A wall material shell acts as an intermediary barrier surrounding each phosphorescent core. This shell prevents direct interaction between phosphorescent molecules from adjacent capsules, eliminating self-quenching while allowing energy transfer to occur within each capsule. The wall material also serves as a moisture and oxygen barrier, protecting the phosphorescent material
2Ease of operation
If phosphorescent OLED devices are exposed to environment, then device operation is enabled, but moisture and oxygen permeation causes black spots and reduces lifespan
Solution Approach 1:
Each phosphorescent particle is enclosed in a flexible thin film shell (wall material) with thickness optimized for both mechanical integrity and barrier performance. This shell provides effective protection against moisture and oxygen permeation, preventing the formation of black spots while maintaining device operability. The microcapsule structure allows for flexible device design and manufacturing
Solution Approach 2:
The encapsulation is segmented at the microcapsule level rather than requiring a continuous encapsulation layer for the entire device. This segmentation approach provides effective protection against environmental degradation while simplifying the manufacturing process and reducing the complexity of encapsulation structures
3Reliability
If encapsulation technology is used to protect OLED devices, then moisture and oxygen protection is improved, but surface irregularities and microcracks occur
Solution Approach 1:
The encapsulation function is segmented into numerous individual microcapsules distributed throughout the device, eliminating the need for large continuous encapsulation layers. This segmentation inherently prevents surface irregularities and microcracks that plague traditional encapsulation methods, as each microcapsule is too small to create visible surface defects or stress concentration points
Solution Approach 2:
Encapsulation protection is applied locally at the microcapsule level rather than uniformly across the entire device surface. This local quality approach allows the bulk of the device surface to remain smooth and uniform, while protection against moisture and oxygen is provided at the specific locations where phosphorescent material is present
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 microencapsulation reduces self-quenching, enhances brightness by 20-50% and extends the lifespan of phosphorescent OLED devices by preventing chemical reactions with moisture and oxygen, improving display quality and longevity.
Implementation Method 1
the wall material also has the effect to prevent moisture and/or oxygen in environment from permeating into the core material
Implementation Method 2
the phosphorescent material tends to experience self-quenching for the triplet state of molecular excitation
Data Source
AI summary
The present invention, which belongs to the technical field of display technology, provides a microcapsule, a method of preparing the same, and an OLED (organic light emitting diode) display device comprising the same. The OLED display device comprises a microcapsule having a phosphorescent material as a core material, which reduces the probability of the phosphorescence self-quenching and is isolated from water and oxygen, thereby improving the display quality and extending the service life of the OLED display device. Therefore, the OLED display device can solve the problem that the phosphorescence OLED display device in the prior art has a low brightness and short service life.