Copper Oxide Silicon Tandem Solar Cell Eutectic Deposition
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Solution Overview
Problem
Current copper oxide solar cells have low photovoltaic efficiency, with the highest reported efficiency for Cu2O absorber devices being only 5%, making them non-competitive in the market, despite the potential for higher efficiency based on calculated material limits.
Innovation Solution
A silicon film is deposited onto a highly textured oxide buffer layer using a silicon-copper eutectic melt, followed by oxygen introduction to form a textured Cu2O film, creating a high-efficiency tandem solar cell through the solid phase eutectic deposition process, which can be implemented on various substrates like soda-lime glass, polymers, or metal tapes, allowing for low or high temperature deposition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional copper oxide solar cells are used, then the manufacturing process is simple and cost-effective, but the photovoltaic efficiency is low (only 5%)
Solution Approach 1:
The patent creates a tandem solar cell structure combining copper oxide (Cu2O) and silicon (Si) layers. The Cu2O top cell with wide bandgap (2.2 eV) captures high-energy photons, while the Si bottom cell with lower bandgap (1.1 eV) captures lower-energy photons, achieving synergistic effect and high efficiency up to 45% while maintaining cost-effectiveness through low-temperature deposition processes
2Manufacturing precision
If high efficiency is achieved through materials engineering, then photovoltaic efficiency can exceed 20% (up to 45%), but the fabrication process becomes more complex
Solution Approach 1:
The solar cell is divided into two functional segments: a Cu2O top cell for high-energy photon absorption and a Si bottom cell for low-energy photon absorption. This segmentation allows each layer to be optimized independently while maintaining a relatively simple overall fabrication process using sequential deposition
Solution Approach 2:
The patent changes the deposition temperature parameter to enable low-temperature processing on soda-lime glass substrates. By controlling the temperature regime and using eutectic alloy deposition, high-quality Cu2O and Si layers are formed without requiring complex high-temperature equipment, thus achieving high efficiency with simplified fabrication
3Ease of manufacture
If low temperature deposition is used on soda-lime glass, then cost is reduced and ease of manufacture is improved, but temperature control precision must be maintained
Solution Approach 1:
The patent utilizes phase transition of the copper-silicon eutectic alloy system to enable controlled deposition at low temperatures. By leveraging the eutectic melting point and solidification behavior, precise temperature control is achieved during deposition on soda-lime glass substrates, forming high-quality crystalline layers without requiring extreme temperature precision equipment
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 method achieves high efficiency up to 45% for copper oxide solar cells by combining the wide bandgap of Cu2O with the lower bandgap of Si, facilitating the production of high-efficiency tandem solar cells and other electronic devices like LEDs and thin-film transistors, while being cost-effective and adaptable to different substrates.
Implementation Method 1
Following the solid phase eutectic deposition process disclosed by P. Chaudhari in U.S. Pat. No. 9,054,249 B2, a silicon film is deposited onto a highly textured oxide buffer layer on soda-lime glass from a silicon-copper eutectic melt
Implementation Method 2
Oxygen is introduced to the Cu on Si film and a textured Cu2O film is formed on the textured silicon film
Implementation Method 3
a technology for achieving high efficiency copper oxide solar cells in a cost effective manner is disclosed for the first time... the highest reported photovoltaic efficiency for a Cu2O absorber device is only 5%
Data Source
AI summary
A method of making a copper oxide/inorganic thin film tandem semiconductor device including the steps of: depositing a textured buffer layer on an amorphous substrate, depositing a copper-inorganic film from a solid phase eutectic alloy on said buffer layer, and introducing O2 to the copper on said inorganic film, forming a copper oxide thin film on said inorganic film.