Multi-source Deposition for Perovskite Film Uniformity
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Solution Overview
Problem
Existing fabrication techniques struggle to produce highly uniform perovskite films with good stoichiometry, which is essential for advanced solar cell and optoelectronics applications such as bandgap engineering, multi-junction cell fabrication, and heterostructure construction, due to limitations in achieving high crystallinity and uniformity.
Innovation Solution
A multi-source deposition system and method involving a chamber with multiple evaporation units and a substrate stage that rotates to control the deposition of halide materials and organic compounds, allowing for independent evaporation control and optimized growth parameters to achieve uniform perovskite films with precise composition and thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional vacuum evaporation techniques are used, then fabrication cost is reduced, but film uniformity and stoichiometry deteriorate
Solution Approach 1:
The patent segments the deposition process into multiple sequential steps using a multi-source deposition system. Different source materials (MAI, PbI2, and halide sources) are deposited in separate controlled stages, allowing precise stoichiometry control for each layer while maintaining cost-effectiveness through vacuum evaporation techniques.
Solution Approach 2:
The patent implements local quality control by using individual evaporation sources for different materials positioned at specific locations around the substrate. Each source can be independently controlled to deposit materials with precise local composition, ensuring uniform stoichiometry across the entire film while maintaining fabrication efficiency.
2Ease of manufacture
If solution processing is used, then fabrication cost is reduced, but film crystallinity and uniformity deteriorate
Solution Approach 1:
The patent replaces the chemical solution processing mechanism with a physical vapor deposition mechanism. By using vacuum evaporation to deposit materials directly from vapor phase onto the substrate, the method achieves superior crystallinity and uniformity while maintaining cost-effectiveness, eliminating the need for complex solution processing steps.
3Device complexity
If existing fabrication techniques are used, then device complexity is reduced, but bandgap engineering capability and multi-junction fabrication capability deteriorate
Solution Approach 1:
The patent designs a universal multi-source deposition system that can fabricate various perovskite compositions and structures through programmed deposition sequences. The same apparatus can produce single-junction, multi-junction, and tandem cell structures by controlling the deposition of different material layers, providing adaptability for bandgap engineering while maintaining reasonable process complexity.
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 system enables the production of highly crystalline and uniform perovskite films, suitable for various advanced applications, with controlled layer thickness and composition, enhancing the performance of solar cells and optoelectronic devices.
Implementation Method 1
a first set of evaporation units comprising one or more evaporation units, each coupled to the side section or the bottom section of the chamber, for generating vapors of one or more first source materials with one or more first evaporation rates
Implementation Method 2
a substrate stage configured to rotate around its central axis at a rotation speed
Implementation Method 3
The resultant perovskite film includes multiple unit layers, wherein each unit layer is formed by one rotation of the substrate stage
Implementation Method 4
The system enables the production of highly crystalline and uniform perovskite films
Data Source
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AI summary
A system and method for fabricating a perovskite film is provided, the system including a substrate stage configured to rotate around its central axis at a rotation speed, a first set of evaporation units, each coupled to the side section or the bottom section of the chamber, a second set of evaporation units coupled to the bottom section, and a shield defining two or more zones having respective horizontal cross-sectional areas, which are open and facing the substrate, designated for the two or more evaporation units in the second set. The resultant perovskite film includes multiple unit layers, wherein each unit layer is formed by one rotation of the substrate stage, and the composition and thickness of the unit layer are controlled by adjusting at least the evaporation rates, the rotation speed and the horizontal cross-sectional areas.