Transparent Conductive Layer for Crystalline Solar Cells
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Solution Overview
Problem
Conventional crystalline solar cells face challenges with thermal stress and high manufacturing costs due to the firing process, which can lead to degradation of the transparent conductive layers and adhesion issues between metal and transparent conductive materials, ultimately affecting the long-term stability and performance of the solar cells.
Innovation Solution
A method for manufacturing a crystalline solar cell where a first optically transparent, electrically conductive material is applied after the optically opaque material, avoiding the firing step, and using a PECVD process to deposit the transparent conductive material directly before adding an antireflection layer, ensuring improved adhesion and reduced thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a firing process is used to form electrical contacts on the front face, then direct contact between the electrically conductive material and the semiconductor material is achieved, but thermal stress is generated causing degradation of the transparent conductive layer and adhesion issues
Solution Approach 1:
The harmful firing process is completely removed from the manufacturing sequence. The patent applies the transparent conductive material after the opaque contact material is deposited, eliminating the high-temperature step that causes thermal stress and adhesion degradation while maintaining electrical functionality.
Solution Approach 2:
The transparent conductive material is applied in advance before the antireflection layer, ensuring proper adhesion and electrical contact formation without requiring subsequent high-temperature processing. This preliminary application establishes the conductive pathway before final optical layers are added.
2Ease of manufacture
If the transparent conductive material is applied before the opaque contact material, then the manufacturing process is simplified, but adhesion issues occur between the metal contacts and the transparent conductive material
Solution Approach 1:
The conventional sequence is inverted: instead of applying transparent conductive material first and then metal contacts, the patent deposits the opaque contact material first on the passivation layer, followed by the transparent conductive material. This reversal ensures the metal contacts bond directly to the passivation layer with full adhesion strength while the transparent layer is deposited afterward without compromising the interface.
3Reliability
If the entire front face is contacted by transparent conductive material, then electrical conductivity is improved, but manufacturing costs increase due to the firing process
Solution Approach 1:
The expensive and complex firing process is completely extracted from the manufacturing流程. The patent achieves full-area electrical contact through a low-temperature deposition sequence where transparent conductive material is applied over the entire front face after the opaque contacts, eliminating the need for high-temperature processing while maintaining conductivity.
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 enhances the electrical conductivity and reduces manufacturing costs, improving the performance and long-term stability of the solar cells by eliminating the need for high-temperature firing and ensuring better adhesion of the conductive layers.
Implementation Method 1
using a PECVD process to deposit the transparent conductive material
Data Source
AI summary
A monofacial or bifacial crystalline solar cell, on the front face of which over the entire area a first surface passivation layer is arranged directly on the semiconductor interface and above this a first optically opaque, electrically conductive material is arranged in first lateral regions as a front face contact, and a first optically transparent, electrically conductive material is arranged exclusively in second lateral regions. The first optically transparent, electrically conductive material is electrically conductively connected to the front face contact and to a first region of the semiconductor material of the solar cell. The method provides for application of the first optically transparent, electrically conductive material only after the first optically opaque, electrically conductive material has been applied, in such a way that firing of the front face contact is avoided.