Flexible Substrate Barrier for Thin-Film PV
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Solution Overview
Problem
Rigid glass substrates used in thin-film photovoltaic cell deposition are costly and inefficient due to high processing requirements, equipment needs, and fragility, making them unsuitable for low-cost, high-yield commercial manufacturing.
Innovation Solution
The use of flexible substrates and roll-to-roll processing for thin-film photovoltaic cell manufacturing, which allows for compact, cost-effective vacuum systems and reduced heat capacity, along with the application of amorphous diffusion barrier layers to improve surface smoothness and reduce contamination, facilitating efficient deposition of semiconductor layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If rigid glass substrates are used for thin-film photovoltaic cell deposition, then structural stability is improved, but manufacturing cost increases and substrate fragility worsens
Solution Approach 1:
The patent changes the physical state and mechanical properties of the substrate from rigid glass to flexible materials (polyimide, stainless steel, titanium). This parameter change enables roll-to-roll processing, reduces substrate thickness, and eliminates the need for complex handling equipment while maintaining sufficient structural stability for PV cell fabrication.
Solution Approach 2:
The patent employs flexible substrate materials including polyimide films and thin metal foils (stainless steel, titanium) with thicknesses ranging from 1-50 micrometers. These flexible substrates enable continuous roll-to-roll processing, reduce weight, and eliminate fragility issues associated with rigid glass while providing adequate mechanical support for the thin-film photovoltaic structure.
2Stability of the object's composition
If rigid glass substrates are used for thin-film photovoltaic cell deposition, then structural stability is improved, but processing complexity and equipment requirements increase
Solution Approach 1:
The patent employs flexible substrate materials including polyimide films and thin metal foils (stainless steel, titanium) with thicknesses ranging from 1-50 micrometers. These flexible substrates enable continuous roll-to-roll processing, reduce weight, and eliminate fragility issues associated with rigid glass while providing adequate mechanical support for the thin-film photovoltaic structure.
Solution Approach 2:
The patent replaces complex mechanical handling systems required for rigid glass substrates with a simplified roll-to-roll processing system. The flexible substrates can be continuously fed through deposition chambers on rolls, eliminating the need for fragile substrate handling, positioning, and support structures required for rigid glass processing.
3Temperature
If rigid glass substrates are used for thin-film photovoltaic cell deposition, then heat capacity is improved for thermal stability, but energy consumption increases due to high heat capacity
Solution Approach 1:
The patent changes the thermal parameters of the substrate by using thin flexible substrates (1-50 micrometers) with lower heat capacity compared to thick rigid glass. This parameter change reduces the energy required for heating during deposition processes while maintaining adequate thermal stability through the inherent properties of the thin-film structure and controlled processing temperatures.
4Manufacturing precision
If rigid glass substrates are used for thin-film photovoltaic cell deposition, then surface smoothness is improved, but manufacturing yield decreases due to substrate fracture
Solution Approach 1:
The patent employs flexible substrate materials including polyimide films and thin metal foils (stainless steel, titanium) with thicknesses ranging from 1-50 micrometers. These flexible substrates enable continuous roll-to-roll processing, reduce weight, and eliminate fragility issues associated with rigid glass while providing adequate mechanical support for the thin-film photovoltaic structure.
Solution Approach 2:
The patent applies preliminary surface treatment and deposition of barrier layers (such as molybdenum or aluminum oxide) on the flexible substrates before semiconductor layer deposition. This preliminary action ensures adequate surface smoothness and prevents contamination or diffusion issues that would otherwise arise from the flexible substrate surface, thereby maintaining manufacturing precision while enabling high-yield production.
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 reduces manufacturing costs, minimizes substrate fracture, and enhances cell efficiency by providing a smooth surface for semiconductor growth, leading to improved open circuit voltage and fill factor, while allowing for lightweight and cost-effective shipping and assembly of solar modules.
Implementation Method 1
an amorphous diffusion barrier layer is deposited onto the substrate and configured to have a surface with roughness less than the predetermined roughness threshold
Implementation Method 2
facilitating efficient deposition of semiconductor layers
Data Source
AI summary
Thin film photovoltaic cells and methods of manufacturing such cells that include one or more diffusion barrier layers configured to provide a relatively smooth growth surface for subsequent deposition of a p-type semiconductor layer. Diffusion barrier layers according to the present teachings may be amorphous, microcrystalline or nanocrystalline layers of materials including molybdenum, conductive oxides, conductive nitrides, conductive carbides, or mixtures thereof. In some cases a diffusion barrier layer may be configured to have surface roughness less than a predetermined threshold value.