TOPCon Solar Cell Passivation Stack With TCO to Cut Light Absorption
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Solution Overview
Problem
The parasitic light absorption of the doped polysilicon layer in tunnel oxide passivated contact (TOPCon) solar cells reduces photovoltaic conversion efficiency.
Innovation Solution
A passivation medium layer comprising a transparent conductive oxide layer, such as aluminum-doped zinc oxide, is introduced to reduce parasitic absorption and enhance surface passivation, combined with a tunnel oxide layer to form a stacked structure that facilitates charge carrier transport and reduces recombination current density.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a doped polysilicon layer is used in the passivation medium layer of TOPCon solar cells, then surface passivation is provided, but parasitic light absorption increases which reduces photovoltaic conversion efficiency
Solution Approach 1:
The patent changes the material parameter of the passivation medium layer from doped polysilicon to transparent conductive oxide (TCO) materials such as aluminum-doped zinc oxide (AZO), gallium-doped zinc oxide (GZO), or indium tin oxide (ITO). This material substitution fundamentally alters the optical and electrical parameters, achieving high transparency in the visible spectrum while maintaining good electrical conductivity and surface passivation properties, thereby resolving the contradiction between passivation effectiveness and light absorption losses
Solution Approach 2:
The patent employs composite material structures where the TCO layer is combined with the tunnel oxide layer and potentially other functional layers. This composite approach leverages the complementary properties of different materials: the tunnel oxide provides excellent interface passivation, while the TCO layer provides both electrical conductivity and optical transparency, together achieving superior performance that neither material could provide alone
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 solution improves the conversion efficiency of solar cells by minimizing parasitic absorption and carrier recombination, enhancing the overall performance of the photovoltaic system.
Implementation Method 1
a first tunnel oxide layer disposed on the first surface of the substrate and at least partially in contact with the first surface; and a passivation medium layer disposed on a surface of the first tunnel oxide layer away from the substrate, the passivation medium layer including at least a transparent conductive oxide layer
Implementation Method 2
the passivation medium layer including at least a transparent conductive oxide layer... improves charge carrier transport and reduces recombination current density
Implementation Method 3
Under the cooperation between the first tunnel oxide layer and the transparent conductive oxide layer, good surface passivation effect can be provided, parasitic absorption can be reduced, and charge carrier transport can be facilitated, thereby reducing the charge carrier recombination current density
Data Source
AI summary
A solar cell, a preparation method thereof, a photovoltaic module, and a photovoltaic system, wherein the solar cell includes a substrate and a first tunnel oxide layer and a passivation medium layer sequentially stacked on a first surface of the substrate. The first tunnel oxide layer is at least partially in contact with the first surface. The passivation medium layer includes at least a transparent conductive oxide layer.