Microporous TOPCon Passivated Contact for Conductivity and Passivation
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Solution Overview
Problem
Conventional TOPCon solar cells face a mutual constraint between conductivity and passivation properties, making it difficult to optimize both simultaneously due to the thickness of the tunneling oxide layer affecting the passivation effect and interface defect density.
Innovation Solution
A passivated contact structure with a passivation oxide layer thickness of 1.5 nm to 3.5 nm and nanoscale micropores, combined with a doped crystalline silicon layer, enhances conductivity by creating direct conduction channels while maintaining effective passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the thickness of the tunneling oxide layer is increased to improve passivation effect, then the passivation property is improved, but the conductivity deteriorates
Solution Approach 1:
The patent introduces nanoscale micropores into the passivation oxide layer to create dual-function pathways: the micropores provide direct conduction channels for majority carriers while the bulk oxide maintains high passivation quality. This porous structure resolves the contradiction by allowing both improved passivation (through increased thickness) and maintained conductivity (through micropore pathways).
Solution Approach 2:
The patent creates a composite structure combining the passivation oxide layer with embedded micropores and a doped crystalline silicon layer. This composite architecture enables the system to simultaneously achieve high passivation quality and low series resistance, as the micropores and doped layer work together to provide conduction pathways while the oxide layer provides passivation.
2Reliability
If the thickness of the tunneling oxide layer is increased to reduce interface defect density, then the passivation property is improved, but the conductive property deteriorates
Solution Approach 1:
The nanoscale micropores penetrate through the thicker passivation oxide layer, providing direct conduction pathways that bypass the oxide barrier. This allows the oxide layer to be thicker (reducing interface defects) while maintaining conductivity through the micropore channels.
Solution Approach 2:
The micropores act as intermediary structures that mediate between the thick passivation oxide layer and the doped crystalline silicon layer, enabling carrier transport without requiring thin oxide that would compromise interface quality.
3Loss of energy
If a thin tunneling oxide layer is used to achieve certain conductivity, then the conductive property is improved, but the passivation effect deteriorates
Solution Approach 1:
The microporous structure provides dedicated conduction pathways through the oxide layer, allowing the bulk oxide to be thicker for better passivation while the micropores ensure adequate conductivity.
Solution Approach 2:
The oxide layer is functionally segmented into two regions: the bulk oxide providing passivation and the micropore regions providing conduction pathways. This segmentation allows each region to optimize its function independently.
4Loss of energy
If a thin tunneling oxide layer is used to achieve certain conductivity, then the conductive property is improved, but the interface defect density increases
Solution Approach 1:
The micropores provide conduction pathways that eliminate the need for thin oxide, allowing the use of thicker oxide that produces fewer interface defects while maintaining conductivity through the porous structure.
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 modified structure optimizes passivation effects and reduces series resistance, improving both conductivity and passivation properties of the solar cell.
Implementation Method 1
A plurality of nanoscale micropores are distributed in the passivation oxide layer... enhances conductivity by creating direct conduction channels
Implementation Method 2
achieves surface passivation through a tunneling and passivated contact structure formed by a tunneling oxide layer and a doped polysilicon layer
Data Source
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AI summary
The present application relates to a passivated contact structure, a solar cell and a preparation method therefor, and a photovoltaic module. The passivated contact structure comprises a passivation oxide layer arranged close to a silicon wafer of a solar cell and a doped crystalline silicon layer away from the silicon wafer, wherein the thickness of the passivated oxide layer is 1.5 nm to 3.5 nm, and several nanoscale micropores are distributed in the passivated oxide layer.