Solar Cell Step Morphology for Lower Recombination Loss
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Solution Overview
Problem
Conventional solar cells suffer from poor photoelectric conversion efficiency due to high contact recombination loss between metal electrodes and doped layers, as well as parasitic absorption of incident light by the doping layer, which limits the utilization of incident light and overall performance.
Innovation Solution
A solar cell design featuring a substrate with a metal pattern region and a non-metal pattern region, where the doped layer is formed in the non-metal region and a passivation contact structure is used over the metal region, reducing contact recombination and parasitic absorption, and a step morphology is created to increase the action area of the doped layer, enhancing light utilization and carrier transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a doped layer is formed on the substrate surface to enhance passivation effect, then carrier recombination on the substrate surface is inhibited, but contact recombination loss between metal electrodes and the doped layer increases
Solution Approach 1:
The solar cell surface is divided into metal pattern regions and non-metal pattern regions, with the doped layer selectively formed only in the non-metal pattern regions. This segmentation allows the metal electrodes to contact the substrate directly in metal regions (reducing contact recombination loss) while maintaining passivation in non-metal regions through the doped layer.
Solution Approach 2:
Different regions of the substrate surface are given different structures and properties: metal pattern regions have direct metal-substrate contact for efficient carrier collection, while non-metal pattern regions have a doped layer for enhanced passivation. This local differentiation optimizes both contact performance and passivation effect simultaneously.
2Reliability
If a doped layer is formed on the substrate surface to enhance passivation effect, then carrier recombination on the substrate surface is inhibited, but parasitic absorption of incident light by the doping layer increases
Solution Approach 1:
The doped layer is segmented to be formed only in non-metal pattern regions, allowing incident light to reach the substrate directly in metal pattern regions without passing through the doped layer, thereby reducing parasitic absorption while maintaining passivation where the doped layer is present.
Solution Approach 2:
The doped layer is selectively applied to non-metal pattern regions where passivation is needed, while metal pattern regions remain free of the doped layer to minimize light absorption. This local quality differentiation balances passivation requirements with light utilization efficiency.
3Productivity
If the action area of the doped layer is increased to improve photoelectric conversion, then light utilization is enhanced, but the device structure becomes more complex
Solution Approach 1:
The doped layer is extended into the substrate along the depth dimension in non-metal pattern regions, creating a three-dimensional structure that increases the action area without expanding the planar footprint. This vertical extension allows more light to interact with the doped layer while maintaining a compact overall structure.
Solution Approach 2:
The doped layer is selectively formed with different depths and concentrations in different regions (first region closer to the rear surface, second region at intermediate depth), creating localized variations that optimize photoelectric conversion without requiring uniform complex structures throughout the entire device.
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 significantly reduces contact recombination loss and parasitic absorption, improving the photoelectric conversion efficiency by increasing the action area of the doped layer and enhancing light utilization, resulting in higher open-circuit voltage, filling factor, and conversion efficiency.
Implementation Method 1
each of the at least one first passivation contact substructure includes a first tunneling layer and a first doped conductive layer stacked in a direction away from the substrate
Implementation Method 2
The emitter can form a PN junction with the substrate
Implementation Method 3
the emitter can form a PN junction with the substrate, and the doping film with passivation effect can be used to inhibit carrier recombination on the surface of the substrate
Implementation Method 4
the doping film with passivation effect can be used to inhibit carrier recombination on the surface of the substrate of the solar cell and enhance the passivation effect on the substrate
Implementation Method 5
metal electrodes used to collect carriers also need to be prepared in the solar cell. Generally, the metal electrodes are electrically connected to the doped layer to collect the carriers
Data Source
AI summary
A solar cell is disclosed, including a substrate having a first surface and an opposite second surface, and a first passivation contact structure. The first surface has a metal pattern region and a non-metal pattern region including a first region and a second region. The first region is closer to the second surface than the metal pattern region, and the second region is not closer to the second surface than the first region and is not further away from the second surface than the metal pattern region. The substrate has a doped layer formed in a portion of the substrate corresponding to the non-metal pattern region, and the doped layer has a top surface at the non-metal pattern region. The first passivation contact structure covers the metal pattern region and includes at least one first tunneling layer and at least one first doped conductive layer.