Kaust: discovery of a process to improve the efficiency of solar panels by 27%

Photovoltaic energy is clean energy since it does not cause greenhouse gas emissions. As it is also a renewable energy, its adoption is encouraged across the world. Some countries, Japan among others, even impose the use of this type of energy.

Although it is now possible to produce a colossal amount of electricity to power thousands of homes from a photovoltaic infrastructure, the yield is far from optimal. It is for this reason that scientists from King Abdullah University of Science and Technology (KAUST) in Saudi Arabia conducted research aimed at tuning the structure of perovskite/silicon tandem solar cells.

Improving Tandem Solar Cells

In fact, unlike single-junction silicon solar cells, tandem solar cells use two different materials to capture light in a single module. This can have an advantage since the hardware in this case is theoretically able to generate much more power.

To verify this hypothesis, KAUST researchers implemented new materials capable of extracting an electrical charge from the silicon side. They also ensured that the amount of light reaching the perovskite layer increased.

“Silicon-based tandem solar cells have been identified as the ultimate long-term technology to further improve the energy conversion efficiency of solar panels (…) We are therefore focusing on this technology,” Stefaan said. De Wolf, an electrical engineer who led the research.

New contact materials

“Overall, we allowed more light to be captured in the tandem solar cell and we converted the absorbed sunlight into energy more efficiently with our new contact materials,” added Erkan Aydin, reports Theengineer.co.uk.

According to the explanations of this expert who participated in the study, when semiconductors such as silicon and perovskites absorb light, "the electrons are collected at the level of the 'n-type contacts' on one side of the material , and the positively charged holes are collected at the “p-type contacts” on the opposite side”.

It should be noted that the “p” side, that is to say positive, is generally facing upwards in single-junction thin-film perovskite solar cells; a provision that has recently allowed them to exceed a return of 25%.

Power conversion efficiency greater than 27%

KAUST scientists have relied on this recent exploit to improve the concept. Their research aimed to overcome the obstacles preventing tandem perovskite/silicon solar cells from generating more power. To do this, the team used spiro-TTB.

It is a transparent contact material. The performance of the layers on the negative side has also been improved by using a contact material based on niobium oxide.

“Overall, we allowed more light to be captured in the tandem solar cell and we converted the absorbed sunlight into energy more efficiently with our new contact materials,” Aydin said. . Their research is said to have resulted in a power conversion efficiency of over 27%. Solar panels adopting this concept will therefore be more efficient in terms of energy yield. Unfortunately, we do not know if the technology is ready for commercialization yet.