Solution-Processable Tungsten Oxide Buffer Layers for Organic Electronics
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Solution Overview
Problem
Current methods for manufacturing tungsten oxide hole injection layers in organic electronics, such as OLEDs and OPVs, face challenges including the use of solvent-based processes that can damage active layers, require additional cleaning treatments, and are not suitable for hydrophobic substrates due to wettability issues and residual organic materials affecting electronic properties.
Innovation Solution
A composition of tungsten oxide nanoparticles in a solvent composition with azeotropic water content and a specific ratio of nanoparticles to water, allowing for solution deposition on various substrates without vapor phase processes, resulting in thin films with low residual organic content and improved stability and wettability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solvent-based processes are used to deposit tungsten oxide layers, then the deposition can be performed without vapor phase processes, but the solvent can damage active organic layers in OLEDs or OPVs
Solution Approach 1:
The patent changes the chemical parameters of the solvent system by selecting specific solvents with appropriate polarity and boiling points that are less aggressive toward organic layers. The solvent composition is carefully controlled to achieve both effective deposition and compatibility with sensitive organic electronic components.
Solution Approach 2:
The patent employs a single-step deposition process where the solvent serves its purpose during deposition and then evaporates completely, leaving no residual damage. The solvent acts as a temporary carrier that is discarded through evaporation, avoiding the need for additional cleaning steps that could harm organic layers.
2Stability of the object's composition
If polymeric dispersing agents are used for particle stabilization, then the suspension stability is improved, but the dispersing agent remains in deposited layers and negatively impacts electronic properties
Solution Approach 1:
The patent extracts and removes the harmful polymeric dispersing agents from the final deposited layer through careful selection of volatile solvents and controlled drying conditions. The dispersing agents are eliminated during the evaporation process, leaving only the functional tungsten oxide nanoparticles in the deposited layer.
Solution Approach 2:
The patent changes the physical parameters of the drying process, controlling temperature and time to ensure complete evaporation of volatile components while maintaining nanoparticle integrity. This allows the use of dispersing agents during deposition that can be completely removed afterward, resolving the contradiction between stability and purity.
3Stability of the object's composition
If water-based dispersions are used, then the suspension can be prepared with electrostatic particle stabilization, but the dispersions cannot be applied on hydrophobic substrates due to bad wettability
Solution Approach 1:
The patent creates a composite solvent system that combines the benefits of both polar and non-polar characteristics. This hybrid solvent composition enables the suspension to wet both hydrophobic and hydrophilic substrates effectively while maintaining electrostatic particle stabilization, thus achieving universal substrate compatibility.
Solution Approach 2:
The patent develops a universal solvent composition that performs multiple functions: it stabilizes particles through electrostatic mechanisms, enables wetting of hydrophobic substrates, and allows for complete evaporation without residues. This multi-functional solvent system resolves the contradiction between particle stabilization and substrate adaptability.
4Reliability
If additional cleaning treatments by temperature annealing or plasma treatment are applied, then the electronic properties of the HIL layer are improved, but the organic functional layers and substrates are damaged
Solution Approach 1:
The patent converts the potential harm of solvent residues into a benefit by selecting solvents that evaporate completely under mild conditions. The evaporation process itself becomes the cleaning mechanism, eliminating the need for aggressive annealing or plasma treatments that would damage organic layers, while still achieving excellent electronic properties.
Solution Approach 2:
The patent employs a self-cleaning deposition process where the solvent system automatically removes itself through complete evaporation, leaving a clean interface between the tungsten oxide layer and organic functional layers. This self-service mechanism eliminates the need for external cleaning treatments that could cause damage.
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 deposition of tungsten oxide nanoparticle layers on both hydrophobic and hydrophilic substrates with enhanced stability and film formation, reducing the need for high-temperature annealing and plasma treatments, and producing thin films with low surface roughness and residual organic content.
Implementation Method 1
Due to the fact that WO3 exhibits an isoelectric point at about pH 1, the WO3 particles are negatively charged at pH 7 in water resulting in electrostatic particle stabilization.
Implementation Method 2
a homogeneous solvent composition comprising water and an organic solvent, wherein the solvent composition has an azeotropic water content
Data Source
AI summary
The present invention relates to the field of organic electronics, such as OLEDs, OPVs and organic photo detectors. It particularly provides intermediates and materials suitable for manufacturing such organic electronics, to specific manufacturing methods and to specific uses.