The layer works like an iron diffusion barrier and prevents corrosion and oxidation of the carrier.

Scientists at INM - Leibniz Institute for New Materials have developed a barrier layer that separates the metal carrier from the absorber film, increasing the efficiency of metal-based CIGS solar cells.

Apart from other influences, corrosion and poor isolation between substrate and carrier material cause a low efficiency in CIGS solar cells.

Now the scientists have developed a glass-like barrier layer which improves the solar cell efficiency.  “It works as iron diffusion barrier and thus prevents corrosion and oxidation of the carrier", explains Peter William de Oliveira, head of the program division.

“At the same time, the barrier works as insulating layer and reduces unintentional electrical currents from the absorber to the carrier," he continues. Both functions increase the efficiency of metal-based CIGS solar cells by up to 13 %.

The glass-like diffusion barrier is applied on the metal carrier by means of the sol-gel process. It is transparent and flexible and has a thickness of only a few microns. The INM scientists developed both the layer and up-scaled process. By means of dip coating and slot coating they produced foils in a DIN A3 size. The traditional roll-to-roll printing process allows the production of continuous layered foils up to a length of 50 metres and a width of about half a metre.

INM – Leibniz Institute for New Materials will present its results at the nano tech 2011 conference in Tokyo from 16th to 18th February 2011 in the German Pavilion (Booth E-18-24).

A recently published study by Lux Research confirms that the cost of goods sold for CIGS solar cells will rapidly decrease over the coming years. According to this study, an increased efficiency, among other things, will contribute to a gross margin of over 30 percent.