Single-Layer White Light Emission via Polymer-Phosphor Merging
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Solution Overview
Problem
Existing white light emitting organic electroluminescent devices suffer from low performance and high complexity, making them unsuitable for industrial applications that require efficient, cost-effective, and mass-producible thin organic electroluminescent devices with high color purity.
Innovation Solution
A composition comprising a first conjugated polymer and a phosphorescent small molecule emitter, where the concentration of the phosphorescent small molecule emitter is below 4 wt.%, and the peak photoluminescence wavelengths of the components complement each other to generate white light, allowing for the production of devices with a single emissive layer and excellent performance data.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-layered OLED structure with multiple functional layers is used, then device performance and light emission quality are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent combines multiple functional layers (emissive layer, electron transport layer, hole transport layer) into a single integrated emissive layer containing both fluorescent and phosphorescent emitters. This merging approach maintains the light emission quality and device performance of multi-layer structures while significantly reducing device complexity and manufacturing steps.
Solution Approach 2:
The single emissive layer performs multiple functions simultaneously: it acts as both the fluorescent emission layer and the phosphorescent emission layer, and also provides electron transport and hole transport functionalities. This multi-functionality eliminates the need for separate functional layers while maintaining device performance.
2Use of energy by moving object
If phosphorescent emitters are used in OLEDs, then energy efficiency and power consumption are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges fluorescent and phosphorescent emission mechanisms into a single emissive layer, allowing the device to benefit from the high energy efficiency of phosphorescent emitters (utilizing both singlet and triplet excitons) while avoiding the complexity of separate phosphorescent layers and associated manufacturing challenges.
3Device complexity
If single emissive layer with multiple emitters is used, then device complexity is reduced, but achieving desired color coordinates becomes difficult
Solution Approach 1:
The patent employs specific emitters with carefully selected emission wavelengths and quantum efficiencies: a blue fluorescent emitter (460-480 nm), a green phosphorescent emitter (520-540 nm), and a red phosphorescent emitter (620-650 nm). By optimizing the local properties (wavelength, efficiency) of each emitter component, the desired color coordinates (CIE 1931: x=0.32, y=0.33) are achieved despite the simplified 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
The solution enables the production of white light emitting devices with high efficiency, long lifetime, and high color purity, suitable for industrial applications, with simplified manufacturing processes and reduced production costs.
Implementation Method 1
at least one phosphorescent small molecule emitter
Implementation Method 2
the peak photoluminescence wavelengths of the components complement each other to generate white light
Data Source
AI summary
The present invention relates inter alia to compositions comprising conjugated polymers and a small molecule, devices comprising the composition and the application of the devices.