Conductive Paste Using Metallic Glass for Solar Cell Electrodes
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Solution Overview
Problem
Conductive pastes used in solar cells often have lower conductivity due to the inclusion of non-electroconductive glass frit, necessitating an improvement in electrode conductivity for enhanced solar energy conversion efficiency.
Innovation Solution
A conductive paste comprising a conductive powder, a metallic glass with a supercooled liquid region, and an organic vehicle, where the metallic glass exhibits liquid-like behavior between its glass transition and crystallization temperatures, allowing for improved wetting and diffusion into semiconductor layers, and the formation of a buffer layer that reduces contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conductive paste including non-electroconductive glass frit is used to form an electrode, then the electrode can be formed by a simplified process, but the conductivity of the electrode is reduced
Solution Approach 1:
The patent changes the chemical composition parameters of the glass frit by incorporating specific metal elements (Cu, Ag, Ni, Co, Zn, Al, or Si) to transform it from a non-electroconductive material into an electroconductive material. This parameter change enables the glass frit to provide both the binding function and electrical conductivity in the electrode paste, resolving the contradiction between ease of manufacture and electrode conductivity.
Solution Approach 2:
The patent creates a composite material system where conductive metal powders are combined with electroconductive glass frit containing specific metal elements. This composite approach allows the paste to achieve both processability (from the glass frit binder) and high conductivity (from the conductive metal network), simultaneously satisfying ease of manufacture and reliability requirements.
2Reliability
If the conductivity of the conductive paste is increased to improve electrode performance, then charge transfer efficiency is improved, but the complexity of the paste composition increases
Solution Approach 1:
The electroconductive glass frit serves multiple functions simultaneously: it acts as a binder to hold the conductive powder particles together, provides a conductive pathway for charge transfer, and forms a buffer layer to reduce contact resistance. This multi-functionality increases charge transfer efficiency without proportionally increasing paste composition complexity.
Solution Approach 2:
The electroconductive glass frit acts as an intermediary material between the conductive powder particles and the semiconductor substrate. It facilitates charge transfer by creating a buffer layer that reduces contact resistance, thereby improving charge transfer efficiency while maintaining a relatively simple paste formulation.
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 use of this conductive paste enhances the conductivity of electrodes, leading to improved charge transfer and reduced losses in solar cells, thereby increasing the efficiency of solar energy conversion.
Implementation Method 1
The supercooled liquid region may be between a glass transition temperature and a crystallization temperature of the metallic glass. In the supercooled liquid region, the metallic glass may show a liquid-like behavior.
Implementation Method 2
a metallic glass having a supercooled liquid region... The supercooled liquid region may range from about 5° C. to about 200° C.
Implementation Method 3
In the supercooled liquid region, the conductive powder may diffuse into at least one of the metallic glass and the semiconductor layer.
Data Source
AI summary
According to an example embodiment, a conductive paste includes a conductive powder, a metallic glass having a supercooled liquid region, and an organic vehicle. The metallic glass may include an alloy having a disordered atomic structure that includes at least two metals. An electronic device and/or solar cell may include an electrode formed using the conductive paste. An electrode formed using a conductive paste according to example embodiments may have lower contact resistance than an electrode formed using a conductive paste that includes glass frits instead of a metallic glass.