TOPCon Solar Cell Structure With Dual-Doped Polysilicon Passivation
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Solution Overview
Problem
The existing passivation structures in solar cells, such as TOPCon solar cells, face limitations in improving conversion efficiency due to high doping concentration in polysilicon layers affecting passivation and open-circuit voltage, leading to recombination issues and reduced efficiency in mass production.
Innovation Solution
A solar cell design with a semiconductor substrate featuring a first doped conductive layer with low concentration and a retardation layer in the metallization region, and a second doped conductive layer with higher concentration covering both metallization and non-metallization regions, optimizing passivation and carrier transport while minimizing recombination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single heavily doped polysilicon layer is used in the metallization region, then good electrical contact is achieved, but passivation performance deteriorates and recombination loss increases
Solution Approach 1:
The single doped polysilicon layer is segmented into two distinct layers: a first doped polysilicon layer in contact with the semiconductor substrate and a second doped polysilicon layer above it. This segmentation allows each layer to have optimized doping concentrations for their specific functions, resolving the contradiction between electrical contact and passivation performance.
Solution Approach 2:
Different regions of the polysilicon structure are assigned different doping concentrations. The first doped polysilicon layer has a doping concentration of 1×10^19 to 1×10^21 atoms/cm³ for good passivation, while the second doped polysilicon layer has a higher doping concentration of 1×10^20 to 1×10^22 atoms/cm³ for excellent electrical contact. This local quality differentiation resolves the contradiction between passivation and electrical contact.
2Reliability
If high doping concentration is used in the polysilicon layer, then electrical conductivity is improved, but open-circuit voltage and passivation performance decrease
Solution Approach 1:
The polysilicon structure is divided into two layers with different doping concentrations, allowing the first layer to maintain lower doping for high open-circuit voltage and passivation, while the second layer provides high doping for electrical conductivity. This segmentation resolves the contradiction between open-circuit voltage and electrical conductivity.
Solution Approach 2:
The first doped polysilicon layer uses lower doping concentration (1×10^19 to 1×10^21 atoms/cm³) to preserve open-circuit voltage and passivation properties, while the second doped polysilicon layer uses higher doping concentration (1×10^20 to 1×10^22 atoms/cm³) to ensure electrical conductivity. This local quality approach resolves the contradiction between open-circuit voltage and electrical conductivity.
3Reliability
If passivation is enhanced to reduce recombination, then conversion efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The passivation structure is segmented into two doped polysilicon layers with different doping concentrations, allowing each layer to contribute to passivation while maintaining manufacturing feasibility. The first layer provides primary passivation contact with the substrate, while the second layer enhances overall passivation performance, resolving the contradiction between conversion efficiency and manufacturing complexity.
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 design enhances the passivation effect and photoelectric conversion efficiency by reducing recombination current density and increasing the theoretical open-circuit voltage, ensuring effective lateral transport of carriers and improved solar cell performance.
Implementation Method 1
a tunneling layer formed over the second surface of the semiconductor substrate
Implementation Method 2
a first doped conductive layer and a retardation layer formed on a surface of the tunneling layer, the first doped conductive layer is located between the tunneling layer and the retardation layer
Implementation Method 3
the retardation layer is configured to retard migration of a doped element in the second doped conductive layer to the first doped conductive layer
Data Source
AI summary
A solar cell, a manufacturing method thereof, and a photovoltaic module. The solar cell includes: a semiconductor substrate including first and second surfaces opposite to each other; emitter and first passivation layer formed over the first surface; tunneling layer formed over the second surface; first doped conductive layer and retardation layer formed on the tunneling layer and corresponding to metallization region, the first doped conductive layer is located between the tunneling layer and the retardation layer; second doped conductive layer formed over the tunneling layer and covering the tunneling layer in non-metallization region and the retardation layer, the retardation layer is configured to retard migration of doped element in the second doped conductive layer to the first doped conductive layer; second passivation layer formed over the second doped conductive layer; and second electrode forming contact with the second doped conductive layer and first electrode forming contact with the emitter.