Mass Polymerizable Polycycloolefin Compositions for OLED Light Extraction
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Solution Overview
Problem
Existing organic light emitting diode (OLED) technologies face challenges such as inefficient light extraction due to refractive index mismatch, sensitivity to moisture, oxygen, temperature, and the need for stable and active organic filler materials that can mass polymerize under suitable actinic conditions.
Innovation Solution
A single component composition comprising a palladium compound, a photoacid generator, olefinic monomers, and a photosensitizer, which undergoes mass vinyl addition polymerization upon exposure to actinic radiation, forming a transparent optical layer with tailored refractive index, high transparency, and good thermal properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional OLED structures are used, then device fabrication is straightforward, but light extraction efficiency is limited to about 50% due to refractive index mismatch
Solution Approach 1:
The patent changes the refractive index parameter of the organic filler material from conventional values to specifically 1.7-1.9, matching the refractive index of the glass substrate. This parameter change enables light waves to propagate through the substrate without being trapped by total internal reflection, increasing light extraction efficiency from 50% to 80-90%.
Solution Approach 2:
The patent creates a composite material system consisting of the organic filler material with refractive index 1.7-1.9 combined with the mass polymerizable composition. This composite structure allows the filler to provide refractive index matching while the polymerizable component provides protective and functional properties.
2Adaptability or versatility
If OLEDs are used, then opto-electronic functionality is achieved, but materials are sensitive to moisture, oxygen, and temperature
Solution Approach 1:
The patent applies a thin film of the mass polymerizable composition over the OLED structure. This thin film acts as a protective barrier that shields the sensitive organic materials from moisture and oxygen while maintaining the opto-electronic functionality of the device.
Solution Approach 2:
The patent creates a composite protective layer combining the mass polymerizable composition with the OLED structure. This composite material provides both protective properties against environmental degradation and maintains the functional properties of the underlying OLED.
3Reliability
If mass polymerizable compositions are used, then protective coatings can be formed, but premature polymerization occurs at room temperature
Solution Approach 1:
The patent introduces a photoacid generator as an intermediary component that remains inactive at room temperature but activates the palladium catalyst upon exposure to actinic radiation. This intermediary mechanism allows the composition to remain stable during storage and handling while enabling controlled polymerization only when needed for protective coating formation.
Solution Approach 2:
The patent changes the activation parameter from thermal (temperature-based) to photonic (radiation-based). By using actinic radiation as the trigger instead of heat, the composition remains stable at room temperature during storage but can be rapidly activated to form protective coatings when exposed to UV light during device fabrication.
4Productivity
If photopolymerization is used for coating formation, then rapid solidification occurs, but control over polymerization timing is difficult
Solution Approach 1:
The patent uses the photoacid generator as a controlled intermediary that mediates between the actinic radiation and the palladium catalyst. The photoacid generator activates only upon UV exposure, providing precise control over when polymerization occurs, while still enabling rapid coating formation once activated.
Solution Approach 2:
The patent performs preliminary preparation by mixing all components (palladium catalyst, monomer, photoacid generator) into a stable composition that remains inactive during storage. The actual polymerization action is then triggered only when needed during device fabrication by exposing to actinic radiation, enabling both rapid formation and precise timing control.
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 composition achieves enhanced light extraction efficiency, stability at room temperature, and rapid polymerization upon exposure to actinic radiation, forming solid objects with high transparency and desirable thermal properties, suitable for various opto-electronic applications.
Implementation Method 1
which undergoes mass vinyl addition polymerization upon exposure to actinic radiation
Implementation Method 2
a photoacid generator, olefinic monomers, and a photosensitizer, which undergoes mass vinyl addition polymerization upon exposure to actinic radiation
Data Source
AI summary
Embodiments in accordance with the present invention encompass compositions comprising a heteroaryl compound ligated palladium compound, a photoacid generator, a photosensitizer and one or more olefinic monomers which undergo vinyl addition polymerization only when said composition is exposed to a suitable actinic radiation to form a substantially transparent film. The composition of this invention exhibit unusual shelf-life stability and are photolytically active even in the presence of air. The monomers employed therein have a range of optical and mechanical properties, and thus these compositions can be tailored to form films, including thin films, having various opto-electronic properties even under atmospheric conditions without the need of inert atmosphere. Accordingly, compositions of this invention are useful in various applications, including as coatings, encapsulants, fillers, leveling agents, among others.