Conductive Paste for Solar Cells Using Metallic Glass
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Solution Overview
Problem
Conductive pastes used in solar cells often have low conductivity due to the inclusion of glass frit, making it difficult to achieve high efficiency in electrical energy production from solar energy, as they require complex and costly deposition methods or have low conductivity when using screen printing.
Innovation Solution
A conductive paste comprising a conductive powder, a metallic glass with specific alloy properties, and an organic vehicle, where the metallic glass includes elements with low resistivity and high oxidation potential, forming a solid solution with the conductive powder to enhance conductivity and prevent oxidation, resulting in improved electrode formation with reduced contact resistance and resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conductive paste including glass frit is used for screen printing, then the manufacturing process is simplified, but the conductivity of the electrode is reduced
Solution Approach 1:
The patent removes glass frit from the conductive paste formulation. The conductive paste according to the invention consists essentially of conductive powder and organic vehicle, explicitly excluding glass frit that would otherwise be included in conventional conductive pastes. This extraction of the harmful component resolves the contradiction by enabling high conductivity while maintaining screen printing simplicity.
Solution Approach 2:
The patent uses composite conductive powder particles comprising a core shell structure with a metal core and a metal oxide shell. This composite structure provides both high conductivity (from the metal core) and good adhesion to semiconductor substrates (from the metal oxide shell), resolving the contradiction between ease of manufacture and electrode reliability.
2Reliability
If a deposition method is used to fabricate an electrode, then the conductivity is improved, but the process becomes complicated and costly
Solution Approach 1:
The patent employs a disposable conductive paste formulation that can be applied via simple screen printing. The paste contains conductive powder with specific properties (core shell structure, particle size distribution) that enable high conductivity without requiring complex deposition equipment or processes. This approach replaces expensive, complex deposition methods with a simple, one-time application process.
Solution Approach 2:
The patent changes key parameters of the conductive material: using conductive powder with 0.1-45 μm particle size, core shell structure with metal oxide shell thickness of 1-50 nm, and specific metal compositions. These parameter changes enable the material to achieve high conductivity through simple screen printing rather than requiring complex deposition processes.
3Stability of the object's composition
If glass frit is included in the conductive paste, then the paste formulation is conventional and stable, but the electrode contact resistance increases
Solution Approach 1:
The patent explicitly excludes glass frit from the conductive paste formulation. The conductive paste consists essentially of conductive powder and organic vehicle only. This extraction eliminates the source of high contact resistance while the organic vehicle provides sufficient formulation stability for screen printing application.
Solution Approach 2:
The patent uses composite conductive powder particles with metal core and metal oxide shell. The metal oxide shell provides stable adhesion to semiconductor substrates, while the metal core provides low contact resistance. This composite structure achieves both formulation stability and low contact resistance without using glass frit.
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 conductive paste significantly improves the conductivity of electrodes, reducing contact resistance and resistivity, thereby enhancing the efficiency of solar cells by allowing better charge transfer and adherence to semiconductor substrates, leading to more effective solar energy conversion.
Implementation Method 1
the metallic glass includes an alloy of at least two elements selected from an element having a low resistivity, an element which forms a solid solution with the conductive powder
Implementation Method 2
an element having a high oxidation potential has an absolute value of a Gibbs free energy of oxide formation of about 100 kiloJoules per mole or greater
Data Source
AI summary
A conductive paste including a conductive powder, a metallic glass, and an organic vehicle, wherein the metallic glass includes an alloy of at least two elements selected from an element having a low resistivity, an element which forms a solid solution with the conductive powder, or an element having a high oxidation potential, wherein the element having a low resistivity has a resistivity of less than about 100 microohm-centimeters, and the element having a high oxidation potential has an absolute value of a Gibbs free energy of oxide formation of about 100 kiloJoules per mole or greater.