Solar Cell Doped Conductive Layer Raman Optimization
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Solution Overview
Problem
Existing solar cells suffer from low photoelectric conversion efficiency due to excessive carrier recombination in the metal pattern region and differing light receptivity between the front and rear surfaces.
Innovation Solution
A solar cell design featuring a first doped conductive layer on the front surface and a second doped conductive layer on the rear surface, where the full width at half maximum of the Raman spectrum for the first doped conductive layer is smaller than that of the second, optimizing crystallite size and parasitic light absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a doped conductive layer is formed over the front surface of the substrate to achieve field passivation and band bending, then the passivation effect is enhanced, but parasitic light absorption increases and photoelectric conversion efficiency decreases
Solution Approach 1:
The patent applies different doping types (first doping element vs. second doping element) and different Raman spectrum characteristics to different surfaces of the substrate. The front surface uses a first doped conductive layer with a smaller full width at half maximum in Raman spectrum, while the rear surface uses a second doped conductive layer with a larger full width at half maximum. This local differentiation optimizes each surface's function: the front surface minimizes parasitic absorption while maintaining passivation, and the rear surface provides effective field passivation.
2Reliability
If the thickness of the doped conductive layer is increased to improve field passivation, then the passivation effect is enhanced, but light absorption by the doped layer increases and short-circuit current decreases
Solution Approach 1:
The patent optimizes the thickness parameters of the doped conductive layers to achieve a balance between passivation and light absorption. By carefully controlling the thickness of the first and second doped conductive layers, the patent ensures sufficient field passivation while minimizing parasitic light absorption, thereby maintaining high short-circuit current and overall photoelectric conversion efficiency.
3Ease of manufacture
If a single-type doped conductive layer is used on both front and rear surfaces to simplify manufacturing, then the manufacturing process is simplified, but the photoelectric conversion performance is suboptimal due to differing light receptivity between surfaces
Solution Approach 1:
The patent recognizes that the front and rear surfaces of the solar cell have different light receptivity characteristics and applies differently doped conductive layers to each surface. The front surface receives direct sunlight and uses a first doped conductive layer with specific doping elements, while the rear surface uses a second doped conductive layer with different doping elements. This local optimization maximizes photoelectric conversion efficiency by tailoring each surface's electrical properties to its specific optical environment.
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 parasitic light absorption and carrier recombination, leading to improved open-circuit voltage, short-circuit current, and overall conversion efficiency.
Implementation Method 1
a tunnel oxide layer and a doped conductive layer are formed over the surface of the substrate, and the doped conductive layer includes a doping element
Implementation Method 2
the doping element in the doped conductive layer can be used for band bending at the surface of the substrate, which plays an important role in the passivation effect
Implementation Method 3
a full width at half maximum of a first peak of a Raman spectrum for the first doped conductive layer is smaller than a full width at half maximum of a first peak of a Raman spectrum for the second doped conductive layer
Implementation Method 4
Solar cells have good photoelectric conversion capabilities
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Embodiments of the present disclosure relates to the field of solar cells, and in particular to a solar cell and a photovoltaic module. The solar cell includes: a substrate having a front surface and a rear surface opposite to each other; a first tunnel layer and a first doped conductive layer sequentially formed over the front surface of the substrate in a first direction away from the substrate, the first tunnel layer and the first doped conductive layer are each aligned with a metal pattern region on the front surface, and the first doped conductive layer includes a first doping element of a same type as that of a doping element in the substrate; and a second tunnel layer and a second doped conductive layer sequentially formed over the rear surface of the substrate in a second direction opposite to the first direction, the second doped conductive layer includes a second doping element of a different type from that of the first doping element in the first doped conductive layer, and a full width at half maximum near a first peak of a Raman spectrum for the first doped conductive layer is not greater than a full width at half maximum near a first peak of a Raman spectrum for the second doped conductive layer. Embodiments of the present disclosure are conducive to improving the photoelectric conversion performance of solar cells.