Solar Cell Passivation Stack for Low Reflectivity and Carrier Collection
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Solution Overview
Problem
The light absorption efficiency of solar cells is limited by the parameters of the passivation structure, including the type, material composition, and thickness of passivation layers, which restricts the improvement of conversion efficiency.
Innovation Solution
A solar cell structure with a specific configuration of passivation layers, including a first aluminum oxide layer, a second silicon nitride layer with a defined atomic ratio, and a third silicon oxynitride layer, optimized for refractive indices and thickness to enhance light absorption and reduce internal reflection, is employed. The second passivation layer is silicon-rich and has a higher refractive index than the third, and the third layer is designed to absorb short-wave light, while the first layer provides field passivation and carrier transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional passivation structure is used, then the manufacturing process is simple, but the light absorption efficiency is limited
Solution Approach 1:
The patent employs a composite passivation structure consisting of multiple layers with different materials (silicon nitride, silicon oxynitride, aluminum oxide) to achieve both high light absorption efficiency and effective passivation. Each layer contributes different optical and electrical properties, creating a synergistic effect that improves overall solar cell performance while maintaining manufacturing feasibility.
Solution Approach 2:
The patent applies different material compositions and thicknesses to different layers within the passivation structure. The second silicon nitride layer has a specific atomic ratio (n/m = 0.18-0.32) optimized for light absorption, while the third silicon oxynitride layer (j/i = 0.125-1.03) provides complementary optical properties, and the aluminum oxide layer offers field passivation. This local optimization of material properties at different structural levels resolves the contradiction between manufacturing simplicity and performance enhancement.
2Productivity
If the passivation layer parameters are optimized to improve light absorption, then the conversion efficiency increases, but the device complexity increases
Solution Approach 1:
The patent systematically optimizes critical parameters including the atomic ratios of silicon nitride (n/m = 0.18-0.32) and silicon oxynitride (j/i = 0.125-1.03), layer thicknesses (second layer: 40-60 nm, third layer: 10-30 nm), and material compositions. These parameter changes are carefully controlled to achieve maximum light absorption efficiency while maintaining a structured, manageable device architecture that does not excessively increase complexity.
3Productivity
If a multi-layer passivation structure is used to reduce light reflectivity, then the absorption efficiency improves, but the manufacturing precision requirements increase
Solution Approach 1:
The patent specifies precise parameter ranges for each layer to balance performance and manufacturability. The second silicon nitride layer thickness is controlled at 40-60 nm with atomic ratio n/m = 0.18-0.32, and the third silicon oxynitride layer is controlled at 10-30 nm with atomic ratio j/i = 0.125-1.03. These defined ranges provide clear manufacturing targets that achieve high absorption efficiency while remaining feasible for industrial production with standard precision capabilities.
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 configuration significantly reduces light reflectivity, especially in the short-wave range, leading to improved absorption efficiency and increased short-circuit current, resulting in a dark blue or black solar cell with enhanced power generation capabilities.
Implementation Method 1
A solar cell structure with a specific configuration of passivation layers, including a first aluminum oxide layer, a second silicon nitride layer with a defined atomic ratio, and a third silicon oxynitride layer, optimized for refractive indices and thickness to enhance light absorption and reduce internal reflection
Implementation Method 2
optimized for refractive indices and thickness to enhance light absorption and reduce internal reflection
Implementation Method 3
the third layer is designed to absorb short-wave light
Implementation Method 4
the first layer provides field passivation and carrier transmission
Data Source
Figure 1
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AI summary
A solar cell, a method for producing a solar cell and a solar cell module are provided. The solar cell includes: a substrate having a front surface and a rear surface opposite to the front surface; a first passivation layer, a second passivation layer and a third passivation layer sequentially formed on the front surface and in a direction away from the front surface; wherein the first passivation layer includes a dielectric material; the second passivation layer includes a first silicon nitride SimNn material, and a ratio of n/m is 0.5∼1;the third passivation layer includes a silicon oxynitride SiOiNj material, and a ratio of j/i is 0.1∼0.6; and a tunneling oxide layer and a doped conductive layer sequentially formed on the rear surface and in a direction away from the rear surface, wherein the doped conductive layer and the substrate have a doping element of a same conductivity type.