Global Solar Energy Technology

The production process Global Solar Energy applies at its Tucson and its Berlin- Adlershof facilities is based on a Copper Indium Gallium diSelenide (CIGS) material mix.

Step 1 - MOLY

A molybdenum layer is deposited onto the stainless steel film by means of sputtering. All the steps follow a roll to roll procedure, meaning that the steel film is unrolled, coated and rolled up again inside the machines. The moly layer is the solar cell’s rear contact.

Step 2 - CIGS

The active layer that converts sunlight into energy is actually a material composition that is vapour-deposited onto the molybdenum-coated steel band. The Copper, Indium, Gallium and Selenium raw materials enter the machines by means of vaporization sources whose design is primarily a result of proprietary know-how.

Step 3 - CSD

A very thin buffer layer is then applied onto the CIGS layer.

Step 4 - TCO

The top layer of the solar cell requires a transparent but conductive layer (TCO = transparent conductive oxide). This layer is also sputtered like the molybdenum layer, so that very similar machines can be used for both of these processes.

Step 5 - Print

To conduct electricity, a grid of silver paste has to be printed on to later serve as a contact for traces. To do this, special printing systems that unroll the stainless steel band, print it, dry the print, and then roll up the band again are required. The actual solar cell material is complete. However, the entire stainless steel band represents a single, large-scale solar cell with a voltage of only apron. 0.5 V. To make the electrical energy generated usable, higher system voltages are required.

Step 6 - Slit/string

In the first step in this machine, the steel band with dimensions of 700 m - 1000 m x 0.3 m is cut into individual solar cells that typically measure 10 cm x 21 cm. The individual cells are electrically connected to form rows, meaning that the front of one cell is connected to the rear of the next one. The solar strips created this way are typically 1.85 m long and 21 cm wide. Their electrical properties, especially efficiency, are then tested and classified in categories.
That completes the final step in the production cycle of turning these raw materials into CIGS thin-film string. They can be further processed in a number of solar module factories (currently approx. 150 worldwide). The product is light, flexible and unbreakable: worldwide delivery is easy and low-cost.