Aggregated Precursor for Uniform Solar Cell Absorption Layers
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Solution Overview
Problem
Existing methods for manufacturing light absorption layers in solar cells, particularly using the ink coating method, face challenges in achieving uniform composition and stability against oxidation, leading to inefficient film formation and potential impurities.
Innovation Solution
The development of an aggregated precursor comprising a copper-containing chalcogenide and an indium or gallium-containing chalcogenide, where 30% or more of the precursor is divided into particle aggregates and independent particles in an ink solvent, ensuring a uniform composition and increased Group VI element content, facilitating the formation of a stable and dense light absorption layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If mixed Cu-Se and In-Se compound particles are used as precursors, then the coating process can be performed, but the coating layer has a partially non-uniform composition
Solution Approach 1:
The patent uses composite particles consisting of CuSe and In2Se3 phases combined in a 1:1 weight ratio. This composite structure ensures that both copper and indium elements are present in each particle, enabling uniform distribution during coating while maintaining ease of manufacture. The composite nature resolves the contradiction by providing both process feasibility and composition uniformity simultaneously.
Solution Approach 2:
The precursor is segmented into discrete particles with specific size ranges (0.1-10 μm for CuSe, 0.1-5 μm for In2Se3). This segmentation allows for controlled coating and uniform distribution across the substrate. The particles are further segmented into specific phase compositions, ensuring that each particle contributes equally to the final film composition, thereby achieving uniformity while maintaining manufacturability.
2Manufacturing precision
If CuInSe2 single-phase particles are used as precursors, then a uniform composition can be achieved, but long reaction time for particle growth is required
Solution Approach 1:
The patent performs preliminary preparation of CuSe and In2Se3 particles before the main coating process. These particles are pre-synthesized with controlled sizes and compositions, eliminating the need for long in-situ growth reactions during coating. This preliminary action achieves uniform composition distribution while significantly reducing the overall processing time, as the particles are ready for immediate coating without requiring extended reaction periods.
Solution Approach 2:
Instead of using pure CuInSe2 single-phase particles that require complete formation reactions, the patent uses a partial approach by combining pre-formed CuSe and In2Se3 particles in specific ratios. This partial action strategy achieves the desired uniform composition through controlled mixing rather than complete reaction, thereby reducing the time required for particle growth while maintaining composition uniformity.
3Productivity
If the light absorption layer is formed with sufficient thickness, then photoelectric efficiency is improved, but the amount of Group VI element (S or Se) must be increased to prevent oxidation
Solution Approach 1:
The patent changes the particle size parameters of the precursors (CuSe: 0.1-10 μm, In2Se3: 0.1-5 μm) to optimize the formation of the light absorption layer. These parameter changes enable sufficient film thickness to be achieved with controlled Group VI element content. The specific size ranges allow for better packing and densification during coating, improving photoelectric efficiency without requiring excessive sulfur or selenium content, thus resolving the contradiction between thickness and oxidation prevention.
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 approach results in a thin film with a uniform composition, enhanced stability against oxidation, and improved film density, leading to superior photoelectric efficiency and reduced processing costs compared to traditional methods.
Implementation Method 1
30% or more aggregated precursors based on the total weight of the precursors are divided into particle aggregates including first phases and/or second phases, or independent particles having first phases or second phases in an ink solvent
Implementation Method 2
the coated material is heat-treated
Data Source
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AI summary
Disclosed are an aggregated precursor for manufacturing a light absorption layer of solar cells comprising a first phase comprising a copper (Cu)-containing chalcogenide and a second phase comprising an indium (In) and/or gallium (Ga)-containing chalcogenide wherein 30% or more aggregated precursors based on the total amount of precursors are divided into particle aggregates comprising first phases and/or second phases, or independent particles having first phases or second phases, in an ink solvent for manufacturing the light absorption layer, and a method of manufacturing the same.