A team of research scientists from the Australian National University (ANU) has had a breakthrough in the efficiency of solar cells, an outcome multiple entities around the world are incessantly attempting to achieve.

The efficiency of a solar cell refers to the part of the energy from sunlight (photons) that can be converted into electricity by the solar cell. The efficiency of the solar cells in a solar photovoltaic system along with a few other factors is responsible for the energy output of the entire solar photovoltaic (SPV) installation.

The team at ANU have achieved a 21.6% solar cell efficiency. This is the highest value attained for perovskite cells that are above specific dimensions. In the current market scenario, rooftop solar panels being installed have an efficiency of 17% to 18%.

“There are three things you’re trying to achieve with solar cells; you’re trying to make them efficient, stable, and cheap. Perovskites are the future of solar cells. With perovskites the efficiency is now competitive, and cost is one of the big selling points. The real challenge now is making them stable enough to be used on a rooftop for example, where they must be able to last 25 to 30 years in extreme temperatures. Ultimately, the aim is to combine these perovskites with silicon in a tandem solar cell. Putting the two materials together can potentially give us higher efficiencies than either one alone. 95% of solar cells are made of silicon at the moment. It’s a very, very good material, but it’s going to reach the upper limit of its efficiency in the next five or ten years. To be able to make a good tandem solar cell you’ve got to have both of your cells operating as efficiently as possible. Because silicon can’t get much better, we’ve been focusing on the perovskite half. When they’re very small it’s difficult to measure them accurately, and it’s not necessarily representative of what would happen if you scaled up. Our result is the highest on a scale that many consider the minimum – one square centimeter,” said associate professor, Thomas White.

Perovskite materials combine chemical elements like carbon, hydrogen, nitrogen, iodine, and lead. Perovskite is a material with a similar crystal structure to calcium titanium oxide and is known as a perovskite structure. The crystal has oxygen at the edge centers. The newly found cell efficiency implies that perovskite cells can produce 216 watts of electrical power per square meter. This result was achieved by a new nanostructured material conjured by Dr. Jun Peng, a co-researcher on the project.

“An efficient solar cell must be able to produce both high voltage and high current. It can be difficult to achieve both at the same time, but the nanostructured layer in our cells makes this possible,” commented Dr. Peng.

The Commonwealth Scientific assessed the results of this endeavor and Industrial Research Organization (CSIRO) Photovoltaic Performance Lab and the project was executed with funds from the Australian Renewable Energy Agency.

Meanwhile, nearly a month ago, researchers at the French Centre de Nanosciences et de Nanotechnologies (C2N) collaborated with researchers at Fraunhofer Institute for Solar Energy Systems (ISE) and others to efficiently capture the sunlight in a solar cell on an ultrathin absorbing layer made of 205 nm-thick gallium arsenide (GaAs) on a nanostructured back mirror. This new process of fabrication achieved an efficiency of nearly 20%.

Recently Mercom also reported on Rice University scientists designing arrays of aligned single-wall the carbon nanotubes to channel mid-infrared radiation and significantly raise the efficiency of solar energy systems. According to the research, the carbon nanotube can be just the device to make solar panels that lose energy through heat far more efficiently.

Image credit: ANU