Inventux – The Technology
Inventux develops and produces thin film photovoltaic modules with absorbers made of amorphous and micro-crystalline silicon layers. Amorphous and micro-crystalline silicon are ideal absorbers in combination, owing to the fact that different band gaps of amorphous and micro-crystalline silicon offer a better utilization of the incoming solar radiation with the advantage of using the same thin film technology for mass production. The combination of an amorphous with a micro-crystalline cell is called micromorphous cell. The micromorphous cell is the consistent advancement and optimization of the tandem cell from amorphous silicon and has the highest efficiency potential of the silicon-based thin film photovoltaics.
Layer composition
For a comparison: The thickness of the absorbing layers is one third of that of a single page in a Harry Potter volume!
The glass, used in two ways, serves as substrate for the thin solar cells and is at the same time component of the later encapsulation of the element. The different layers are successively deposited on the front glass. For the production of the absorber layers the Plasma Enhanced Chemical Vapor Deposition (PECVD) using gaseous silicon hydrogen compounds became generally accepted. The production of the front and back contact layers (Transparent Conductive Oxide – TCO) take place by applying Low Pressure Chemical Vapor Deposition (LPCVD). In contrast to the crystalline technology the production of solar cells and solar module the production technology utilized by Inventux is united in one process cycle.
Production process
For the monolithic integration, which interconnects cells to modules, connections are created between the front contact layer of a cell with the back contact layer of a neighboring cell. Three structuring steps are necessary using laser ablation to locally remove the assigned layer.
The optimal cell width (thus also cell surface) of a thin film module arises from the compromise between surface losses as a result of the structuring lines mentioned, which increase with the number of cells, and ohmic drops in the contacting (TCO) layers, which increases with the cell width.
Silicon
Why did Inventux choose to manufacture silicon thin film solar cells?
- They represent an exceptionally attractive option for the future photovoltaic technology.
- Silicon (Si) has the potential for high efficiency rates.
- Silicon is basically an infinite resource.
- The usage of silicon in kilogram/kWp is 50 times lower than with cristalline cells.
- Silicon-technology has established itself on the market and is considered reliable worldwide.
- Only half the amount of primary energy is required during the production process as with cristalline technology.
- A broad knowledge about the materials exists due to various types of applications of silicon.
- All applied materials and manufacturing processes are non-toxic and ecologically safe.