Solar Cell Passivation Stack for Short-Wavelength Light Absorption
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Solution Overview
Problem
Existing solar cells have limited light absorption efficiency, particularly for short wavelengths, resulting in a blue or grey appearance instead of a black appearance, and existing solutions like chemical etching or adding silicon oxide/nitride do not fully address this issue.
Innovation Solution
A solar cell design featuring a passivation stack with an oxygen-containing dielectric layer, a silicon nitride first passivation layer, and a silicon oxynitride second passivation layer, where the nitrogen and silicon content gradients optimize refractive indices to reduce internal reflection and enhance absorption of short-wavelength light, achieving a darker appearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional passivation structures are used, then manufacturing simplicity is maintained, but light absorption efficiency for short wavelengths is insufficient
Solution Approach 1:
The passivation structure is divided into three distinct layers: an oxygen-containing dielectric layer, a first passivation layer with silicon nitride material, and a second passivation layer with silicon oxynitride material. Each layer has specific thickness and composition parameters that work together to achieve superior light absorption across different wavelength bands while maintaining manageable manufacturing complexity through standardized deposition processes.
Solution Approach 2:
The patent employs a composite passivation structure combining different materials with complementary optical properties. The oxygen-containing dielectric layer provides baseline passivation, the silicon nitride layer contributes to refractive index management, and the silicon oxynitride layer enhances short-wavelength absorption. This multi-material composite approach achieves high light absorption efficiency without excessive manufacturing complexity.
2Productivity
If chemical etching or simple coating methods are used, then process simplicity is maintained, but the blue or grey appearance and limited absorption efficiency persist
Solution Approach 1:
The patent optimizes specific parameters including the thickness of each passivation layer, the oxygen content in the dielectric layer, and the compositional ratios in the silicon nitride and silicon oxynitride layers. By precisely controlling these parameters, the structure achieves enhanced light absorption and a darker appearance while using standard semiconductor manufacturing techniques that maintain ease of manufacture.
Solution Approach 2:
Different regions of the passivation structure have locally optimized properties: the oxygen-containing dielectric layer provides field passivation, the first passivation layer addresses interface quality, and the second passivation layer targets short-wavelength light absorption. This local quality optimization achieves high power generation efficiency without requiring complex manufacturing processes.
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 design improves light absorption efficiency across various wavelength bands, reducing reflectivity and achieving a dark blue or black appearance, thereby increasing power generation efficiency and applicability in different scenarios.
Implementation Method 1
the nitrogen content at the second interface is higher than that at the first interface and the third interface, respectively. A silicon content at the second interface is higher than that at the first interface and the third interface, respectively. An oxygen content at the second interface is lower than that at the first interface and the third interface, respectively
Data Source
AI summary
A solar cell, a manufacturing method therefor, and a photovoltaic module are provided. The solar cell includes a substrate having a front surface and a rear surface, a passivation stack disposed on the front surface, and a tunneling oxide layer and a doped conductive layer disposed on the rear surface. The passivation stack includes an oxygen-containing dielectric layer, a first passivation layer and a second passivation layer. The first passivation layer includes a first interface adjacent to the oxygen-containing dielectric layer and a second interface adjacent to the second passivation layer, the second passivation layer includes a third interface opposite to the second interface, a nitrogen content and a silicon content at the second interface are higher than those at the first interface and the third interface, respectively, and an oxygen content at the second interface is lower than that at the first interface and the third interface, respectively.