CIGS Thin Film Three-Step Chalcogenization Process
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Solution Overview
Problem
Existing solution processes for manufacturing CIGS thin films for solar cells are limited by inefficiencies due to particle boundary recombination, leading to lower performance compared to vacuum processes, and require toxic hydrazine solutions.
Innovation Solution
A three-step chalcogenization process involving heat-treating a CIG oxide thin film under inert gas, followed by selenium and sulfur precursor treatments, to form a Cu2-xSe and then CIGS thin film with a double band gap structure, enhancing particle growth and reducing toxicity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If solution processes are used to manufacture CIGS thin films, then manufacturing cost is reduced and mass production is enabled, but solar cell performance is significantly lower compared to vacuum processes
Solution Approach 1:
The patent applies parameter changes by systematically varying heat treatment temperature, atmosphere composition, and chalcogen precursor conditions across multiple treatment stages. This transforms the solution-process CIGS thin film structure and composition to achieve performance comparable to vacuum processes while maintaining solution process cost advantages
Solution Approach 2:
The patent segments the heat treatment process into multiple distinct stages: initial heat treatment to form metal oxide precursor, first chalcogenization to form Cu2-xSe phase, and second chalcogenization to form final CIGS phase. Each stage uses specific atmospheric conditions and temperature ranges to achieve progressive transformation, enabling precise control over film structure and performance
2Ease of manufacture
If hydrazine solution is used to dissolve precursor metal compounds, then CIGS thin film can be formed by solution process, but additional equipment is required to maintain inert atmosphere due to high toxicity and reactivity
Solution Approach 1:
The patent replaces toxic hydrazine solution with water-based or alcohol-based solutions containing soluble metal salt precursors. These non-toxic solvent systems eliminate the need for complex inert atmosphere equipment while enabling effective dissolution of precursor materials and formation of CIGS thin films through the multi-stage heat treatment process
Solution Approach 2:
The patent changes the chemical parameters of the solution system by using benign solvents (water, alcohols) instead of toxic hydrazine. This parameter change maintains solution process advantages while eliminating safety and equipment complexity issues associated with toxic reagents
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 improves the performance of CIGS thin films by promoting particle growth and reducing recombination losses, achieving higher power conversion efficiency comparable to vacuum-process CIGS solar cells without the use of toxic hydrazine.
Implementation Method 1
first heat-treating a CIG oxide thin film coated on a substrate by a solution process, the heat-treating being performed under an inert gas atmosphere
Implementation Method 2
second heat-treating the CIG oxide thin film while supplying a gaseous phase selenium precursor to the CIG oxide thin film, thereby forming a Cu2-xSe (0≤x<2) phase
Implementation Method 3
the Cu2-xSe phase is formed under an atmosphere including a gaseous phase sulfur precursor, thereby forming a CIGS thin film
Data Source
AI summary
Methods of manufacturing a CIGS thin film for a solar cell are provided. According to the method, a CIGS thin film having an ideal double band gap grade structure with a large particle size may be obtained by heat-treating a solution-treated CIG oxide thin film by a three-step chalcogenization process. Accordingly, performance of the solar cell may be improved.