Segmented P-Type Emitter Structure for Lower Auger Recombination
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Solution Overview
Problem
Existing solar cells have poor photoelectric conversion performance due to high emitter doping concentrations leading to increased Auger recombination and deteriorated passivation, which is exacerbated by the electrical connection of the emitter to a metal electrode.
Innovation Solution
A solar cell design featuring a P-type emitter with first and second portions, where the first portion has pyramid structures with micro-defects and a low sheet resistance, and the second portion has straight edges and a higher sheet resistance, reducing recombination centers and improving ohmic contact and passivation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high doping concentration is used in the emitter, then electrical conductivity is improved, but Auger recombination increases and passivation deteriorates
Solution Approach 1:
The emitter is divided into multiple regions with different doping concentrations. The first region (near the metal electrode contact) has higher doping concentration to ensure good electrical conductivity and ohmic contact, while the second region (towards the p-n junction) has lower doping concentration to reduce Auger recombination and maintain good passivation. This spatial segmentation allows each region to optimize its doping level for its specific function.
Solution Approach 2:
Different regions of the emitter are assigned different local properties (doping concentrations) according to their functional requirements. The contact region receives high doping for conductivity, while the junction-proximal region receives low doping for reduced recombination. This local quality differentiation resolves the contradiction by allowing high conductivity where needed without sacrificing passivation elsewhere.
2Ease of manufacture
If uniform doping is applied across the emitter, then manufacturing is simplified, but photoelectric conversion performance is poor
Solution Approach 1:
The doping process is segmented into at least two distinct doping steps or regions, creating a multi-region emitter structure. While this increases manufacturing complexity compared to uniform doping, it enables optimized photoelectric conversion by reducing Auger recombination in the low-doped region while maintaining conductivity in the high-doped region.
Solution Approach 2:
The doping concentration parameter is changed spatially across the emitter structure, transitioning from uniform doping to graded or multi-level doping. This parameter variation optimizes the balance between conductivity and recombination loss, improving photoelectric conversion efficiency despite increased 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 photoelectric conversion performance by reducing Auger recombination and maintaining good passivation, resulting in improved open-circuit voltage, short-circuit current, and overall efficiency.
Implementation Method 1
high emitter doping concentrations leading to increased Auger recombination
Implementation Method 2
Solar cells have good photoelectric conversion capabilities
Data Source
AI summary
Embodiments of the present disclosure relates to the field of solar cells, and in particular to a solar cell and a production method thereof, and a photovoltaic module. The solar cell includes: a P-type emitter formed on a first surface of an N-type substrate and including a first portion and a second portion, a top surface of the first portion includes first pyramid structures, and a top surface of the second portion includes second pyramid structures whose edges are straight. A transition surface is respectively formed on at least one edge of each first pyramid structure, and each of top surfaces of at least a part of the first pyramid structures includes a spherical or spherical-like substructure. A tunnel layer and a doped conductive layer sequentially formed over a second surface of the N-type substrate. The present disclosure can improve the photoelectric conversion performance of solar cells.