TOPCon Solar Cell Structure With TCO Passivation Layer
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Solution Overview
Problem
Tunnel oxide passivated contact (TOPCon) solar cells face reduced photovoltaic conversion efficiency due to significant parasitic light absorption by the doped polysilicon layer, which is not effectively addressed by existing technologies.
Innovation Solution
A solar cell structure is developed with a substrate having a first tunnel oxide layer and a passivation medium layer, where the passivation medium layer includes a transparent conductive oxide layer, such as aluminum-doped zinc oxide, to reduce parasitic absorption and enhance surface passivation, facilitating charge carrier transport and reducing recombination current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a solar cell structure is designed to simultaneously achieve high open-circuit voltage and high fill factor, then power conversion efficiency is improved, but it becomes difficult to form a tunnel oxide layer and maintain interface quality
Solution Approach 1:
The patent divides the interface structure into multiple functional layers: a first tunnel oxide layer (20 nm-5 nm thickness) and a second tunnel oxide layer (5 nm-20 nm thickness) separated by an intermediate layer. This segmentation allows each oxide layer to be optimized independently - the first layer provides good interface quality and voltage, while the second layer enables good fill factor, resolving the contradiction between achieving high open-circuit voltage and high fill factor simultaneously.
Solution Approach 2:
The patent introduces an intermediate layer between the first and second tunnel oxide layers. This intermediate layer acts as a mediator that facilitates the formation process and maintains interface quality between the two oxide layers, making it easier to form the complete tunnel oxide structure while maintaining high power conversion efficiency.
2Device complexity
If conventional tunnel oxide formation methods are used, then process simplicity is maintained, but interface quality and uniformity deteriorate
Solution Approach 1:
The tunnel oxide formation process is segmented into two distinct oxidation steps: first forming a thin oxide layer (20 nm-5 nm) with good interface quality, then forming a second oxide layer (5 nm-20 nm) with controlled thickness. This segmented approach improves interface quality and uniformity compared to conventional single-step oxidation, while maintaining reasonable process complexity through sequential simple oxidation treatments.
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 structure improves the conversion efficiency of the solar cell by reducing parasitic absorption and carrier recombination, while maintaining adequate electrical conductivity and optical performance.
Implementation Method 1
the first tunnel oxide layer (200) and a passivation medium layer (300) sequentially stacked on a first surface of the substrate... the first tunnel oxide layer (200) is at least partially in contact with the first surface... to improve open-circuit voltage
Implementation Method 2
The passivation medium layer (300) includes at least a transparent conductive oxide layer... to improve fill factor
Implementation Method 3
transparent conductive oxide layer... does not substantially affect light incident on the solar cell
Implementation Method 4
solar cell... light incident on the solar cell... power conversion efficiency
Data Source
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AI summary
A solar cell, a preparation method thereof, a photovoltaic module, and a photovoltaic system, wherein the solar cell includes a substrate (100) and a first tunnel oxide layer (200) and a passivation medium layer (300) sequentially stacked on a first surface of the substrate. The first tunnel oxide layer (200) is at least partially in contact with the first surface. The passivation medium layer (300) includes at least a transparent conductive oxide layer.