Solar cell could beat theoretical efficiency maximum

Scientists have begun developing a new approach that could allow a massive breakthrough in the efficiency of solar panels through the use of nano-particles of germanium, silicon and other materials.

A team made of researchers from both UC Davis and UC Santa Cruz has been awarded a $1.5 million development fund by the National Science Foundation to continue work on the development.

While most conventional solar cells use the principle of ‘one photon in, one electron out’, whereby a photon particle of light hits the solar cell and produces one electron as an electrical current, according to Gergely Zimanyi, a professor at UC Davis, the researchers have been working on a method that will allow many electrons to be produced.

The previous theoretical maximum efficiency of this transfer was capped at 31 percent, however by enabling several particles to be generated from a single photon the maximum can be raised to between 42 and 65 percent.

This high efficiency method has been previously theorised at the Los Alamos National Laboratory, though the researchers say that the Los Alamos group were unable to build a functioning cell based on the idea.

The UC Davis and UC Santa Cruz team believe that through the use of nanotechnology they will be able to make the idea become a reality, constructing a fully functioning solar cell from germanium and silicon nanoparticles.

The researchers will conduct theoretical and computer modelling studies before synthesising the new nano-particles and developing a working device.

A prototype has already been constructed, which, while only reaching eight percent efficiency, demonstrated the functionality on the device even at a very early stage.

However, according to TechEye’s reliable sources in the PV industry, while this may sound like a huge step towards much greater efficiency in solar cells, it is not entirely unusual for university researchers to develop “groundbreaking” technologies that are in reality much more difficult to implement.

“Often high efficiency technology may be developed by researchers at a size of 100cm2, which is very hard to keep stable when up-scaled to a 1.5m by 0.5m module.

“In lab conditions the world is your oyster. You can control the conditions just as you would like, while any work is being done by scientist. In order to be viable commercially the work would instead be done by a skilled worker in a factory which is a very different scenario.

“So in terms such highly efficient technology becoming commercially viable we should not get too excited.”