Solar Paste Additives for Silver-Silicon Bonding
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Solution Overview
Problem
The existing paste compositions for solar cell contacts often result in high series resistance and low shunt resistance, affecting the efficiency and fill factor of solar cells due to inadequate interaction and bonding between silver and silicon interfaces.
Innovation Solution
A paste composition comprising silver, a glass frit, and a metal additive such as yttrium or organo-metal compounds, which are dispersed in an organic vehicle and applied to a silicon substrate, then fired to form low resistance conductive bridges between the silver and silicon, optimizing the microstructure and electrical properties of the front contact interface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional paste composition is used, then the solar cell contact can be formed, but high series resistance and low shunt resistance occur due to inadequate bonding between silver and silicon
Solution Approach 1:
A metal additive (such as copper, nickel, or palladium) is introduced as an intermediary element between silver and silicon. This additive facilitates bonding interaction at the interface, enabling better adhesion and electrical contact. The metal additive acts as a mediator that bridges the incompatibility between silver and silicon, resolving the bonding quality issue without requiring changes to the base paste composition.
Solution Approach 2:
The chemical composition parameter of the paste is modified by adding a metal additive. This changes the interfacial chemistry between silver and silicon, enabling improved bonding and reduced series resistance. The parameter change is specific to the paste formulation rather than the processing conditions or substrate properties.
2Reliability
If conventional paste composition is used, then the contact structure is simple, but inadequate interaction at the silver-silicon interface reduces electrical performance
Solution Approach 1:
A metal additive (such as copper, nickel, or palladium) is introduced as an intermediary element between silver and silicon. This additive facilitates bonding interaction at the interface, enabling better adhesion and electrical contact. The metal additive acts as a mediator that bridges the incompatibility between silver and silicon, resolving the bonding quality issue without requiring changes to the base paste composition.
Solution Approach 2:
The chemical composition parameter of the paste is modified by adding a metal additive. This changes the interfacial chemistry between silver and silicon, enabling improved bonding and reduced series resistance. The parameter change is specific to the paste formulation rather than the processing conditions or substrate properties.
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 proposed solution achieves low series resistance and high shunt resistance, leading to improved solar cell efficiency and fill factor by facilitating optimized interaction and bonding between silver and silicon, thereby enhancing the electrical performance of solar cells.
Implementation Method 1
During the firing, glass softens, melts, and reacts with the anti-reflective coating, etches the silicon surface, and facilitates the formation of intimate silicon-silver contact
Implementation Method 2
glass softens, melts, and reacts with the anti-reflective coating, etches the silicon surface
Implementation Method 3
optimizing the microstructure and electrical properties of the front contact interface... facilitates optimized interaction and bonding between silver and silicon
Implementation Method 4
heating the paste to sinter the silver particles and fuse the glass frit
Implementation Method 5
heating the paste to sinter the silver particles and fuse the glass frit
Data Source
AI summary
Paste compositions, methods of making a paste composition, and methods of making a solar cell contact are disclosed. The paste composition can contain silver, a glass frit, a metal additive and an organic vehicle system. The metal additive is at least one selected from the group consisting of yttrium, an organo-vanadium compound, organo-antimony compound, organo-phosphorus compound, and an organo-yttrium compound. The paste can be used for making a solar cell contact.