The Helmholtz Center Berlin, Fraunhofer Institute for Solar Energy Systems ISE, Soitec, and CEA-Leti have collaborated in developing the world’s most efficient solar cell.
In May 2013, a solar cell with an efficiency of 43.6% was announced from the same team of German and French researchers. A few short months later with a couple new collaborators allowed them to gain a full percentage point, breaking the world record for efficiency at 44.7% at a concentration of 297 suns. A solar cell with 50% efficiency is the ultimate goal from the team.
Efficiency is measured by the percentage of the solar spectrum's energy that is converted to usable electricity. The light on the spectrum ranges from ultraviolet all the way through infrared. The maximum efficiency of a solar panel is equal to the maximum power output, divided by the product of incident radiation flux and the area of the cell. This number is then taken into consideration when determining how many solar panels are needed for a specific location.
The record-breaking solar cells are used in panels that are twice as efficient as regular photovoltaic panels. The concentrator photovoltaics (CPV) were derived from technology used in space. The four-junction solar cells are stacked on top of one another, which allows each cell to absorb a different wavelength of solar light. Additionally, a new technique known as wafer bonding has allowed the team to connect semiconductor crystals; a feat that had previously been incredibly difficult. Wafer bonding allows for a stability of the cell while maintaining an airtight environment.
Drastic increases in efficiency such a short amount of time are encouraging. More efficient solar cells will decrease the price of solar panels while maximizing the area of the panel, allowing those who have space constraints to reap the benefits of solar power.
Enthusiasm for solar power is heating up around the globe. Germany has been at the forefront of solar power implementation. In July, a month that was unseasonably gray and gloomy, they still managed to beat their own wold record of solar power production at 5.1 terawatt hours (TWh). It was recently announced that IKEA would be selling solar panels at all of their stores in the UK (though thankfully, you do not need to assemble it yourself). In the United States, the Department of Defense will have 25% of its total energy (3 GW) come from solar by 2025.