Thin film solar cells
are considered the next generation of solar cells and are expected to be considerably
cheaper because they need much less material and energy in their production
than today’s photovoltaic modules.
Researchers around the globe are racing to develop efficient thin film solar
cells. The solar cells made in Luxembourg are based on a semiconductor made
of copper, indium, gallium and selenium (CIGS) and made by a process with the
potential for highest performance. Furthermore, the scientists of the University
of Luxembourg produced another solar cell based on a new cheaper material, which
does not contain the costly indium, and made by a low cost galvanic process.
This solar cell has reached an efficiency of 3.2 percent. This is already close
to the world record: the worldwide best cell based on this new material and
prepared by a similar low cost process shows an efficiency of 3.4 percent.
The laboratory for photovoltaics of the University of Luxembourg is a group
of researchers developing new materials and processes for solar cells. Of all
the available thin film technologies, solar cells based on CIGS have shown the
highest efficiencies in research and in production. Prof Susanne Siebentritt,
head of the laboratory, explains: “Currently we can produce the heart of
the solar cells, the so called absorber layer and the buffer. But for completing
the solar cells we rely on the help of our colleagues from Helmholtz-Zentrum
Berlin”. The luxembourgish laboratory focuses not only on the development
of solar cells but also on furthering the physical understanding of the materials
and interfaces involved in these solar cells.
The laboratory for photovoltaics (LPV) was founded in April 2007 within the
framework of the TDK Europe professorship, a public-private partnership funded
by TDK corporation and the University of Luxembourg. “We have just a few
months ago moved into our new labs. This allows us finally to start the solar
cell preparation. These are really our first solar cells and they have already
reached competitive efficiencies”, Prof Siebentritt says, “I am very
proud of my team”.