Cuprous Oxide Solar Cell Sputtering Process
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Solution Overview
Problem
Current methods for manufacturing cuprous oxide solar cells face challenges such as low efficiency due to the presence of heterogeneous phases and impurities, which hinder the formation of a favorable pn junction and reduce photoelectric conversion efficiency.
Innovation Solution
A solar cell design incorporating a cuprous oxide photoelectric conversion layer formed by sputtering with controlled oxygen flow and substrate heating, using a transparent conductive oxide electrode to suppress reaction with oxygen, and measuring transmittance and reflectance to minimize heterogeneous phases, resulting in improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a copper foil is oxidized and etched to remove heterogeneous phases, then the solar cell can be manufactured, but the conversion efficiency remains low (about 8%) due to residual heterogeneous phases and impurities
Solution Approach 1:
The patent applies preliminary action by forming the cuprous oxide layer through sputtering with controlled oxygen introduction before final device assembly. This preliminary oxidation step, combined with subsequent annealing treatment, pre-establishes a high-quality photoelectric conversion layer with minimal heterogeneous phases, avoiding the need for post-manufacturing etching and polishing steps that compromise efficiency.
Solution Approach 2:
The patent employs parameter changes by precisely controlling sputtering conditions (oxygen flow rate, power, pressure) and annealing parameters (temperature, atmosphere, duration). These parameter optimizations enable formation of pure cuprous oxide with controlled crystal orientation and minimal defects, achieving high conversion efficiency without requiring aggressive etching or thickening procedures.
2Ease of manufacture
If a thin film is formed by liquid phase reaction method, then the manufacturing process is simple, but the conversion efficiency is low (about 4%) due to impurities and heterogeneous phases incorporated into the film
Solution Approach 1:
The patent replaces the liquid phase chemical reaction method with a physical vapor deposition process (sputtering). This substitution eliminates the need for liquid precursors and chemical reactions, thereby avoiding incorporation of solution impurities and heterogeneous phases into the film, while achieving superior photoelectric conversion efficiency.
Solution Approach 2:
The patent uses an inert or controlled oxygen atmosphere during sputtering and annealing processes. This controlled atmosphere prevents unwanted chemical reactions and impurity incorporation that occur in liquid phase methods, ensuring high purity cuprous oxide film formation with minimal defects and optimal photoelectric properties.
3Manufacturing precision
If the cuprous oxide layer is made thicker to improve light absorption, then the efficiency may increase, but the manufacturing complexity increases due to polishing requirements
Solution Approach 1:
The patent applies preliminary action by forming the cuprous oxide layer with optimal thickness (50-200 nm) directly during the sputtering process, before any subsequent steps. This preliminary formation at the correct thickness eliminates the need for post-manufacturing polishing and thinning operations, reducing manufacturing complexity while ensuring sufficient light absorption for high efficiency.
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 approach enhances the conversion efficiency of cuprous oxide solar cells by reducing heterogeneous phases, increasing transmittance, and improving the quality of the photoelectric conversion layer, leading to higher power generation efficiency.
Implementation Method 1
a cuprous oxide compound photoelectric conversion layer which contains a small number of heterogeneous phases
Implementation Method 2
a cuprous oxide compound made of an inexpensive material and having a wide band gap
Implementation Method 3
substrate heating
Implementation Method 4
using a transparent conductive oxide electrode to suppress reaction with oxygen
Implementation Method 5
a solar cell having a higher efficiency. The tandem solar cell can use a cell with high spectral sensitivity for each wavelength band
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
According to one embodiment, a solar cell includes a first electrode, a second electrode, and a photoelectric conversion layer disposed between the first electrode and the second electrode. When a transmittance of the solar cell is measured in a wavelength range of 700 to 1000 nm, an average of the transmittance of the solar cell is 60% or more.