Why Thin Film

Thin film is a broad term used to describe a variety of different technologies which do not use crystalline silicon cells. The basic thin film cell is made up of amorphous silicon (s-Si) allowing cheaper production, and better absorption of light. This allows the cells to be manufactured thinner than traditional silicon cells and therefore cheaper. In addition the manufacturing process uses much lower temperatures, using less energy in their production and thereby reducing the embedded carbon.

Under real outdoor conditions the operating temperatures of PV can reach 80oC, especially if building integrated due to a lack of ventilation. At this temperature, thin film panels can have a 20% better yield than when compared to traditional crystalline modules of the same power rating.

If a solar cell becomes broken or comes under intense spot shading, the electricity can bypass the cell and continue the flow of electricity. This allows the modules to continue operation where conventional crystalline cells would have a severely reduced output.

alwitra EVALON® Solar uses triple-junction thin film technology which is effectively three layers of thin film PV stacked on top of one another. Each layer is specifically manufactured to absorb a particular portion of the light spectrum, allowing a much greater efficiency than just a single sheet of thin film.

 

Thin Film diagram

 

SOLYNDRA® Solar uses a different technology known as CIGS (Copper Indium Gallium Selenide) which is based on compound semi-conductors as opposed to silicon. Out of the various compound semi-conductors on the market CIGS cells have reached the highest efficiencies in laboratory testing. The SOLYNDRA® Solar panel is shaped to exploit as much of the suns energy as possible from direct sunlight, diffused light and reflected light.

Solyndra Diagram

illustrations by alwitra