CIS Compound Preparation via Composite Particle Thermal Treatment
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Solution Overview
Problem
Conventional methods for preparing CIS (Cu—In—Se) compounds face issues with selenium loss and lack of uniformity in dispersion and reaction among precursor particles, leading to inefficient and large-sized absorption layers in solar cells.
Innovation Solution
The method involves producing composite particles with an indium selenide outer layer coupled to copper selenide seed particles or vice versa, which are then thermally treated to form a CIS compound, enhancing dispersion and reaction uniformity and preventing selenium loss, allowing for the creation of large-grained absorption layers with improved efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If vacuum deposition is used to deposit CuInSe2 on a substrate, then high efficiency absorption layer is achieved, but uniformity deteriorates when making large-sized absorption layer and expensive equipment is needed
Solution Approach 1:
The invention segments the precursor materials into separate Cu powder, In powder, and Se powder particles that are mixed together. This segmentation allows each component to be independently controlled and uniformly distributed before reaction, resolving the uniformity issue while maintaining efficiency through complete reaction of all components.
Solution Approach 2:
The invention uses an organic solvent as an intermediary medium to disperse and mix the Cu, In, and Se powder particles uniformly before thermal treatment. This intermediary approach enables large-sized absorption layers to be made uniformly without requiring vacuum deposition equipment.
2Manufacturing precision
If precursor materials are coated and thermally treated at high temperature to make large-sized absorption layer uniformly, then uniformity is improved, but efficiency of absorption layer becomes low
Solution Approach 1:
The invention changes the physical state parameters of the precursor materials from oxide form to metallic powder form (Cu powder, In powder, Se powder). This parameter change enables complete reaction at lower temperatures while maintaining uniformity, thus achieving both uniform large-sized absorption layers and high efficiency.
Solution Approach 2:
The invention creates a composite structure by mixing Cu powder, In powder, and Se powder in specific ratios before thermal treatment. This composite approach ensures complete reaction and formation of efficient CuInSe2 absorption layer with uniform distribution, resolving the efficiency-uniformity contradiction.
3Ease of manufacture
If metal oxide precursor is used for coating and thermal treatment, then low cost and uniform absorption layer are achieved, but large crystals cannot be obtained resulting in lowered efficiency
Solution Approach 1:
The invention changes the chemical composition parameter of the precursor from metal oxide to metallic powder (Cu, In, Se). This parameter change enables complete reaction and formation of large crystals with high efficiency, while maintaining the low-cost and uniform manufacturing advantages of the coating method.
4Ease of manufacture
If conventional CIS compound preparation method using precursor particles is used, then production is simplified, but selenium loss occurs and dispersion, coupling and reaction uniformity among precursor particles are poor
Solution Approach 1:
The invention segments selenium into fine powder particles that are uniformly mixed with Cu and In powders. This segmentation increases the surface area and reactivity of selenium, preventing loss during reaction while maintaining simple production process and achieving uniform dispersion and coupling among all precursor particles.
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 highly efficient CIS compound thin film with larger crystal sizes, enhancing the performance and efficiency of solar cells by minimizing selenium loss and improving reactant mixing and reaction uniformity.
Implementation Method 1
making a CIS compound by thermally treating composite particles selected from the group consisting of the first composite particles, the second composite particles and their mixtures
Data Source
AI summary
A method for preparing a CIS (Cu—In—Se) compound includes (S1) producing a plurality of first composite particles having an indium selenide outer layer physically coupled to at least a part of a copper selenide seed particle surface or a plurality of second composite particles having a copper selenide outer layer physically coupled to at least a part of an indium selenide seed particle surface; and (S2) making a CIS compound by thermally treating composite particles selected from the group consisting of the first composite particles, the second composite particles and their mixtures. This method may prevent loss of selenium, which inevitably requires selenium environment, and also improves dispersion, coupling and reaction uniformity for the formation of a CIS compound.