Nanoparticle Ink Composition for Flexible Substrate Printing

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Solution Overview

Problem

Current ink formulations based on semiconductor nanoparticles face challenges such as instability, unsuitability for industrial-scale production, and incompatibility with flexible substrates, while also failing to preserve the intrinsic electronic and fluorescence properties of nanoparticles.

Innovation Solution

A stable ink composition comprising conductive/semiconductive metal oxide nanoparticles with 5-15% acetate ligands, mixed with aliphatic and unsaturated alcohols as solvents, a dispersant, and an optional thickener/stabilizer, synthesized through chemical methods that maintain nanoparticle properties and allow for versatile application across various printing methods.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If physical synthesis methods (CVD, thermal evaporation) are used to produce semiconductor nanoparticles, then high purity and controlled morphology are achieved, but high temperatures are required making them unsuitable for flexible substrates and difficult to scale industrially

Engineering Contradiction:
Improvenanoparticle morphology controlVSAvoidindustrial scalability and substrate compatibility
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The patent replaces physical/thermal synthesis methods with chemical synthesis methods. Instead of using high-temperature physical processes like CVD and thermal evaporation, the invention employs chemical reactions in solution to produce semiconductor nanoparticles. This substitution allows synthesis at lower temperatures compatible with flexible substrates while maintaining industrial scalability through solution-based processing.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the synthesis parameters from high-temperature physical conditions to controlled chemical reaction conditions in solution. By adjusting chemical parameters such as precursor concentration, pH, temperature (at much lower levels), and reaction time, the invention achieves precise control over nanoparticle morphology, size, and composition without requiring extreme thermal conditions.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If semiconductor nanoparticles are dispersed in conventional solvents, then they can be processed, but the intrinsic electronic properties and fluorescence characteristics of the nanoparticles deteriorate

Engineering Contradiction:
ImproveprocessabilityVSAvoidelectronic property preservation
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent changes the solvent parameters by selecting specific solvents with appropriate polarity, proticity, and molecular size. The invention identifies that certain solvents (e.g., non-protic solvents with specific dielectric constants) maintain nanoparticle electronic properties while still providing adequate dispersibility. This parameter optimization resolves the contradiction between processability and property preservation.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces surfactants or ligands as intermediary substances between the semiconductor nanoparticles and the solvent. These intermediaries protect the nanoparticle surfaces, prevent aggregation, maintain electronic properties, and simultaneously ensure good dispersibility and processability. The intermediary layer acts as a buffer that preserves intrinsic properties while enabling processing.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If storage stability is improved by adding stabilizers and dispersants, then nanoparticle aggregation is prevented, but the formulation complexity increases and may interfere with electronic properties

Engineering Contradiction:
Improvestorage stabilityVSAvoidformulation complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent employs solvents and surfactants that perform multiple functions simultaneously. The selected solvents provide both dispersion medium functionality and stabilization through their molecular interactions with nanoparticle surfaces. Surfactants serve dual roles as both dispersants and protective agents for electronic properties. This multi-functionality reduces the need for multiple separate additives, simplifying the overall formulation while maintaining stability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent enables the nanoparticle-solvent system to self-stabilize through inherent chemical interactions. The semiconductor nanoparticles and solvent are selected to have compatible chemical properties that naturally prevent aggregation without requiring excessive external stabilizers. The system's own composition provides the stabilization mechanism, reducing formulation complexity.

Inventive Principle:
Principle #25Self-service

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 ink exhibits improved stability, preserved electronic properties, and enhanced fluorescence, enabling efficient use in optoelectronic devices and other applications like photovoltaics and security technologies, with a viscosity range suitable for diverse printing methods.

Implementation Method 1

The ZnO-based ink according to the present invention, once deposited, is characterized by its work function or WF. The work function is the energy required for an electron to go from the Fermi level to the vacuum level. That obtained according to the present invention is stable and constant with temperature and regardless of the support on which the ink is deposited. The mean measured value is preferably of the order of 3.9+/-0.5 eV

Methodology Applied
Scientific EffectWork function:

Implementation Method 2

conservation of fluorescence properties

Methodology Applied
Scientific EffectFluorescence: Fluorescence

Data Source

PatentEP3017008B1Ink compositions comprising nanoparticles
Publication Date: 2021.01.20 GENESINK SA
  • EP3017008B1 patent drawingFigure 1
  • EP3017008B1 patent drawingFigure 2
  • EP3017008B1 patent drawingFigure 3

AI summary

Nanoparticle-based ink composition. The present invention relates to nanoparticle-based ink formulations. In particular, the present invention relates to (semi-)conductive nanoparticle-based ink compositions suitable for different printing methods.