New photovoltaics with improved efficiency and durability
Researchers are continuously experimenting with new materials in an effort to improve upon the efficiency of contemporary photovoltaic (PV) cells, which are currently made primarily from silicon. Wuerth Solar, a German company active in the photovoltaic industry, has achieved noteworthy success with Copper Indium Diselenide (CIS). Wuerth Solar developed prototype PV cells from CIS using the thin film deposition technique. In the framework of the PYTHAGORAS project, these PV prototypes were installed in test sites across Europe (Finland, Germany and Tenerife) to expose them to a wide range of environmental conditions. During PYTHAGORAS, Wuerth Solar managed to improve the efficiency rating of the CIS PV cells from 8% to over 10%. In addition, the DC performance ratio, which compares the cell's performance in real-world conditions to its performance in controlled laboratory conditions, was very high, on the order of 88-96%. Power output of a standard 60 by 120 centimetre module at Standard Test Conditions (STC) reached up to 79 Watts. Regarding the crucial aspect of durability, the results from Finland, Germany and Tenerife indicate that the CIS PV cells are extremely robust. The cells were installed in 2001 and to date no signs of deterioration are evident. The results of accelerated weathering tests also suggest excellent long-term stability. In conclusion, the CIS PV cells produced by Wuerth Solar present advantages both in efficiency and in durability over current silicon-based PV cells. Wuerth Solar is now looking to introduce its mature technology to the market.