Cuprous Oxide Solar Cell Oxidation for Higher Conversion Efficiency

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Solution Overview

Problem

Existing solar cell manufacturing methods do not achieve high conversion efficiency while using cuprous oxide (Cu2O) as a light-absorbing layer.

Innovation Solution

A method for manufacturing a solar cell involving the formation of a p-electrode on a substrate, deposition of a film containing cuprous oxide and/or complex oxides as the main component on the p-electrode, and subsequent oxidation of the film under specific conditions of partial pressure, temperature, and duration to enhance conversion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional oxidation methods are used on cuprous oxide films, then oxidation can be achieved, but conversion efficiency and open-circuit voltage do not reach optimal levels

Engineering Contradiction:
Improveconversion efficiencyVSAvoidoxidation process complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by precisely controlling oxidation conditions including oxygen partial pressure (5000-200000 Pa), water vapor concentration (9.4×10^-1 to 1.0×10^0), and temperature (20-150°C). These parameter optimizations resolve the contradiction by achieving high conversion efficiency (10% or more) and open-circuit voltage (0.70V or more) while maintaining a manageable oxidation process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite light-absorbing layer containing cuprous oxide (Cu2O) and cupric oxide (CuO) in specific proportions (Cu2O: 70-95 atom%, CuO: 5-30 atom%). This composite material approach resolves the technical contradiction by achieving both high conversion efficiency and acceptable manufacturing complexity through controlled oxidation that creates a beneficial mixture of oxidation states.

Inventive Principle:
Principle #40Composite materials

2Reliability

If cuprous oxide is used as a light-absorbing layer, then cost-effectiveness and safety are improved, but conversion efficiency is insufficient

Engineering Contradiction:
Improveconversion efficiencyVSAvoidmaterial composition control
Core Design Contradiction:
ReliabilityVSQuantity of substance

Solution Approach 1:

The patent uses parameter changes to control the oxidation process, adjusting oxygen partial pressure, water vapor concentration, and temperature to achieve optimal CuO formation. This resolves the contradiction by maintaining the simplicity and cost-effectiveness of cuprous oxide material usage while significantly improving conversion efficiency through precise oxidation parameter control.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure with controlled Cu2O and CuO phases, where CuO forms at grain boundaries and interfaces. This composite approach resolves the contradiction by enhancing conversion efficiency through the beneficial effects of CuO while maintaining the overall simplicity and cost-effectiveness of using abundant copper and oxygen materials.

Inventive Principle:
Principle #40Composite materials

3Reliability

If oxidation is performed to enhance performance, then open-circuit voltage and current density increase, but process control difficulty increases

Engineering Contradiction:
Improveopen-circuit voltageVSAvoidoxidation process control
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by establishing specific ranges for oxygen partial pressure (5000-200000 Pa), water vapor concentration (9.4×10^-1 to 1.0×10^0), and temperature (20-150°C). These controlled parameter changes resolve the contradiction by achieving high open-circuit voltage (0.70V or more) and current density while maintaining manageable process control through well-defined parameter windows.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent employs feedback control by monitoring and adjusting oxidation parameters to achieve target CuO concentrations (5-30 atom%). This feedback approach resolves the contradiction by maintaining high open-circuit voltage while simplifying process control through active monitoring and adjustment of oxidation conditions.

Inventive Principle:
Principle #23Feedback

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 method results in a solar cell with improved conversion efficiency, increased open-circuit voltage, and enhanced current density, while maintaining the cost-effectiveness and safety of using Cu2O.

Implementation Method 1

oxidizing the film containing the cuprous oxide and/or the complex oxide of cuprous oxides as a main component. A partial pressure of oxide of the oxidizing is 5000 [Pa] or more and 200000 [Pa] or less

Methodology Applied
Scientific EffectOxidation: Oxidation

Data Source

PatentEP4378008B1Manufacturing method for solar cell
Publication Date: 2025.02.19 KK TOSHIBA
  • EP4378008B1 patent drawingFigure 1~3
  • EP4378008B1 patent drawingFigure 4~7
  • EP4378008B1 patent drawingFigure 8~9

AI summary

A method for manufacturing a solar cell according to an embodiment includes forming a p-electrode on the substrate, forming a film containing cuprous oxide and/or a complex oxide of cuprous oxides as a main component on the p-electrode, and oxidizing the film containing the cuprous oxide and/or the complex oxide of cuprous oxides as a main component. A partial pressure of oxide of the oxidizing is 5000 [Pa] or more and 200000 [Pa] or less. A concentration of vapor water of the oxidizing is 9.4 × 10-1 [g/m3] or more and 2.5 × 103 [g/m3] or less. A temperature of the oxidizing is 40 [degrees Celsius] or more and 150 [degrees Celsius] or less. A duration time of the oxidizing is 10 [sec] or more and 150 [min] or less.