Nano-Zinc Silver Paste for Solar Cell Conductivity
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Solution Overview
Problem
There is a need for zinc-containing compositions in solar cells that offer improved electrical performance, as existing methods and compositions do not fully meet the requirements for enhanced electrical performance and solder adhesion.
Innovation Solution
A thick-film silver paste composition is developed, comprising 80-99% electrically conductive silver powder, 0.1-10% glass frit, and 0.1-10% nano-sized spherical zinc additives (metallic zinc, zinc alloys, or zinc oxide) dispersed in an organic medium, which is applied to semiconductor substrates and fired to form a conductive layer, allowing for improved electrical contact and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional zinc-containing compositions are used, then solder adhesion is maintained, but electrical performance is insufficient
Solution Approach 1:
The patent changes the particle size parameter of zinc additive from conventional micrometer scale to nano-scale (specifically 4-6 m²/gr specific surface area), which fundamentally alters the electrical properties and reactivity of the zinc component, thereby improving electrical performance while maintaining solder adhesion
Solution Approach 2:
The patent creates a composite thick-film paste composition combining silver powder (80-99%), glass frit (0.1-10%), and nano-sized zinc additive (0.1-10%), where the synergistic interaction between these materials achieves both improved electrical performance and maintained solder adhesion that neither material could achieve alone
2Reliability
If zinc additive is added to improve electrical performance, then electrical conductivity increases, but composition complexity increases
Solution Approach 1:
The patent applies local quality by concentrating the zinc additive in specific nano-sized particles with controlled surface area (4-6 m²/gr), creating localized regions of high reactivity and electrical activity within the otherwise uniform silver-glass matrix, thereby improving electrical performance without requiring throughout-composition complexity
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 composition enhances electrical performance and solder adhesion, leading to improved efficiency and reliability of solar cells by forming a robust and effective conductive layer on the front side of solar cells.
Implementation Method 1
firing the semiconductor substrate, insulating film and thick film paste composition, wherein the organic medium is removed, and the silver and glass frit are sintered
Implementation Method 2
0.1 to 10% by weight of a nano-sized, spherical zinc additive having a specific surface area between 4 m2/gr to 6 m2/gr dispersed in an organic medium
Data Source
AI summary
The present invention is a thick film silver composition for use a solar cell device. The thick film paste composition comprises an electrically conductive silver powder, one or more glass frits, a nano-sized additive wherein the nano-sized additive is selected from metallic zinc, zinc alloys or a mixture of metallic zinc and zinc oxide, all dispersed in an organic medium.