Reactive Metal Ink Morphology Control for Photovoltaic Printing
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Solution Overview
Problem
Current photovoltaic device manufacturing processes face challenges with high capital expenditures and limited adoption of innovative technologies due to the high costs and nozzle clogging issues of particle-based silver inks, as well as the requirement for high temperatures in reactive inks, which restricts their use in photovoltaic manufacturing.
Innovation Solution
The development of a system for morphological control of reactive inks using drop-on-demand printing, which allows for precise placement and patterning of metal on substrates at low temperatures, reducing capital expenditures and enabling high precision patterning without sintering, thereby optimizing electrical properties and morphology.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If particle-based silver inks are used for drop-on-demand printing, then electrical conductivity can be achieved, but nozzle clogging occurs and costs are high
Solution Approach 1:
The patent extracts the problematic silver particles from the ink formulation and replaces them with reactive metal precursors (silver salts) dissolved in solvent. This eliminates the particle suspension that causes nozzle clogging while maintaining the ability to form conductive metal deposits through chemical reduction after deposition.
Solution Approach 2:
The patent changes the physical-chemical parameters of the ink by transitioning from a particle-based suspension to a molecularly dissolved precursor solution. This parameter change (from particulate to dissolved state) resolves the clogging issue while the subsequent thermal or chemical processing transforms the dissolved precursors into conductive metal structures.
2Ease of manufacture
If reactive inks are used to avoid particle-based ink issues, then synthesis is easier and oxidation issues are bypassed, but high temperatures are required that restrict substrate types
Solution Approach 1:
The patent modifies the reaction parameters by introducing low-temperature reducing agents that enable metal precursor reduction at temperatures compatible with photovoltaic substrates. This parameter adjustment (lowering reduction temperature) maintains the synthesis advantages of reactive inks while eliminating the substrate temperature restriction.
Solution Approach 2:
The patent introduces intermediary reducing agents (such as hydroxylamine, ascorbic acid, or other mild reducing agents) that mediate the reduction of metal precursors at lower temperatures. These intermediaries enable the reaction to proceed at reduced temperatures without requiring the high temperatures that would damage photovoltaic substrates.
3Reliability
If high temperatures are used for reactive ink processing, then metal complex reduction can be initiated, but substrate selection is limited
Solution Approach 1:
The patent changes the thermal parameters of the reduction process by selecting reducing agents with appropriate activation energies that enable metal precursor reduction at lower temperatures. This parameter modification ensures reliable metal formation while expanding substrate compatibility to include temperature-sensitive photovoltaic materials.
4Quantity of substance
If conventional manufacturing processes are used for photovoltaic devices, then minimum sustainable price is achieved, but capital expenditures are high and growth capacity is limited
Solution Approach 1:
The patent replaces complex mechanical manufacturing systems (screen printing, sputtering, evaporation equipment) with a simplified drop-on-demand printing system that deposits metal precursors directly. This substitution reduces capital expenditures on manufacturing equipment while maintaining production capability and enabling rapid prototyping and customization.
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
This approach enables low-cost, high-performance photovoltaic manufacturing with reduced waste and capital expenditures, achieving dense films with low porosity and electrical resistivity comparable to bulk silver, while allowing for the use of lower temperatures and minimizing nozzle clogging.
Implementation Method 1
the solvent and a temperature of the substrate are controlled during deposition of the reactive metal ink onto the substrate to produce a dense film in the absence of sintering
Implementation Method 2
A temperature of the substrate is maintained between about 60° C. and about 80° C. during deposition of the reactive metal ink onto the substrate
Data Source
AI summary
Systems and methods for optimizing morphology and electrical properties of silver printed on a substrate with a particular implementation in photovoltaic manufacturing techniques. The system comprises a substrate, a printer jet head having a nozzle to dispense a reactive metal ink and a solvent onto the substrate, and wherein the solvent and a temperature of the substrate are controlled during deposition of the reactive metal ink onto the substrate to produce a dense film in the absence of sintering.