Solar Cell Amorphous-Crystalline Layer Segmentation
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Solution Overview
Problem
Solar cells with high power generation efficiency face challenges in balancing passivation and low series resistance, particularly with amorphous semiconductor layers contributing to increased series resistance.
Innovation Solution
A solar cell design incorporating a crystalline semiconductor substrate with alternating regions of amorphous and crystalline semiconductor layers, where the amorphous semiconductor layers provide passivation and the crystalline semiconductor parts reduce series resistance by extending towards the transparent electrode layers, optimizing the proportion and structure of these layers to enhance power generation efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an amorphous semiconductor layer is provided on the crystalline substrate surface for passivation, then passivation quality is improved, but series resistance increases
Solution Approach 1:
The semiconductor layer is segmented into two distinct regions: an amorphous semiconductor layer for passivation and a crystalline semiconductor part for low resistance. This segmentation allows each region to fulfill its specific function optimally without compromising the other.
Solution Approach 2:
Different regions of the semiconductor layer are assigned different material qualities: the amorphous region provides passivation quality while the crystalline region provides low resistance quality. This local differentiation resolves the contradiction by allowing each property to dominate where needed.
2Reliability
If the amorphous semiconductor layer thickness is increased for better passivation, then passivation effectiveness is improved, but power generation efficiency deteriorates due to increased series resistance
Solution Approach 1:
The semiconductor layer is divided into an amorphous portion and a crystalline portion, allowing the amorphous layer to be sufficiently thick for passivation while the crystalline portion provides a low-resistance pathway that compensates for the resistance introduced by the thicker amorphous layer.
Solution Approach 2:
The semiconductor layer is formed as a composite structure combining amorphous and crystalline phases. This composite material approach allows the system to simultaneously exhibit the passivation properties of amorphous material and the high conductivity properties of crystalline material.
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 effectively improves power generation efficiency by achieving both effective passivation and reduced series resistance, leading to enhanced carrier collection and reduced recombination rates.
Implementation Method 1
a first crystalline semiconductor part extending from the one principal surface toward the first transparent electrode layer
Implementation Method 2
An amorphous semiconductor layer is useful for passivation of a crystalline substrate surface
Implementation Method 3
Solar cells having a high power generation efficiency include back surface junction type solar cells
Data Source
AI summary
A solar cell includes: a crystalline semiconductor substrate of a first conductivity type; a first semiconductor layer provided on a first region on one principal surface of the substrate; a second semiconductor layer provided on a second region on the one principal surface different from the first region; a first transparent electrode layer provided on the first semiconductor layer; and a second transparent electrode layer provided on the second semiconductor layer. The first semiconductor layer includes a first amorphous semiconductor layer of the first conductivity type and a first crystalline semiconductor part extending from the one principal surface toward the first transparent electrode layer. The second semiconductor layer includes a second amorphous semiconductor layer of a second conductivity type different from the first conductivity type.