Cuprous Oxide Solar Cell Interface for Transmittance and Defect Control
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Solution Overview
Problem
Current solar cells using cuprous oxide (Cu2O) for light-absorbing layers face challenges in achieving high efficiency and low cost while maintaining good crystallinity and transmittance, with existing configurations often resulting in increased defects and carrier recombination due to composition and layer thickness issues.
Innovation Solution
A solar cell configuration is developed with a p-type light-absorbing layer primarily composed of cuprous oxide, a first n-type layer containing compounds like Gax1M1x2M2x3M4x5Ox6, and an n-electrode, where the composition and thickness of these layers are optimized to reduce defects, enhance carrier concentration, and improve refractive index matching, thereby increasing light transmittance and conversion efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the light-absorbing layer is made thinner to improve light transmittance, then light transmittance is improved, but the light absorption efficiency deteriorates
Solution Approach 1:
The light-absorbing layer is segmented into a cuprous oxide layer and a cupric oxide layer with different functions. The cuprous oxide layer primarily absorbs light, while the cupric oxide layer serves as a buffer to reduce defects and improve carrier concentration, allowing the overall structure to maintain both high transmittance and high absorption efficiency
Solution Approach 2:
The patent uses a composite structure of cuprous oxide and cupric oxide layers. This composite material approach allows combining the high light absorption capability of cuprous oxide with the defect-reducing properties of cupric oxide, achieving both high transmittance and high absorption efficiency simultaneously
2Use of energy by moving object
If the cuprous oxide layer thickness is increased to improve light absorption, then light absorption efficiency is improved, but defects and carrier recombination increase
Solution Approach 1:
The light-absorbing layer is divided into two functional segments: cuprous oxide for light absorption and cupric oxide for defect reduction. This segmentation allows the cuprous oxide layer to be optimized for absorption without excessive thickness, while the cupric oxide layer compensates for defects
Solution Approach 2:
The cupric oxide layer acts as an intermediary between the cuprous oxide layer and the n-type layer, serving as a buffer that reduces defects and improves carrier concentration at the interface, thereby reducing carrier recombination while maintaining light absorption efficiency
3Device complexity
If conventional n-type layers are used to simplify structure, then device complexity is reduced, but refractive index matching and light transmittance deteriorate
Solution Approach 1:
The patent changes the composition parameters of the n-type layer by incorporating multiple elements (Ga, Gr, In, Zn, Sn, Hf, Zr, Ti, Al, B) in specific ratios. This parameter optimization achieves refractive index matching with the cupric oxide layer, improving light transmittance while maintaining structural feasibility
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 optimized configuration enhances the solar cell's conversion efficiency by reducing defects, improving carrier concentration, and increasing light transmittance, making it suitable for use as a top cell in multi-junction solar cells while maintaining low production costs.
Implementation Method 1
A solar cell includes a p-electrode, an n-electrode, a p-type light-absorbing layer between the p-electrode and the n-electrode, and an n-type layer between the p-type light-absorbing layer and the n-electrode
Data Source
AI summary
A solar cell of an embodiment includes a p-electrode, an n-electrode, a p-type light-absorbing layer located between the p-electrode and the n-electrode and mainly containing a cuprous oxide, and a first n-type layer which is located between the p-type light-absorbing layer and the n-electrode, which mainly contains a compound represented by Gax1M1x2M2x3M3x4M4x5Ox6, the M1 being Hf and/or Zr, the M2 being one or more selected from the group consisting of In, Ti, and Zn, the M3 being Al and/or B, the M4 is one or more selected from the group consisting of Sn, Si, and Ge, the x1, the x2, and the x6 being more than 0, the x3, the x4, and the x5 being 0 or more, and the x6 when a sum of the x1, the x2, the x3, the x4, and the x5 is 2 being 3.0 or more and 3.8 or less.