This figure shows the composition of the new perovskite solar cell with silicon nanoparticles, and two scanning electron microscope images of it. Image: ITMO University.
This figure shows the composition of the new perovskite solar cell with silicon nanoparticles, and two scanning electron microscope images of it. Image: ITMO University.

An international research group has improved the efficiency of perovskite solar cells by adding silicon nanoparticles that possess better light absorption properties. Such nanoparticles can trap light of a broad range of wavelengths near the active layer of the solar cell, while not absorbing light themselves or interacting with other elements of the solar cell, thus maintaining its stability. The advance is reported in a paper in Advanced Optical Materials.

Perovskite solar cells have become very popular over the past few years, as perovskites are inexpensive, efficient and easy to use in solar cells. The only problem is that the thickness of the perovskite layer should not exceed several hundred nanometers, even though a thin perovskite layer absorbs fewer incident photons from the Sun.

For this reason, scientists have been looking to find a way to enhance the light harvesting properties of the absorbing perovskite layer without increasing its thickness. One approach involves adding metal nanoparticles, which offer better light absorption abilities due to surface plasmon excitation. Unfortunately, metal nanoparticles also have significant drawbacks; in particular, they tend to absorb some of the solar energy, causing them to heat up and damage the solar cell. Now, scientists from ITMO University in Russia, together with colleagues from St. Petersburg State University in Russia and universities in Italy and the US, propose using silicon nanoparticles to solve these problems.

"Dielectric particles don't absorb light, so they don't heat up," explained Aleksandra Furasova, a postgraduate student at ITMO's Faculty of Physics and Engineering. "They are chemically inert and don't affect the stability of the battery. Besides, being highly resonant, such particles can absorb more light of a wide range of wavelengths. Due to special layout characteristics, they don't damage the structure of the cells. These advantages allowed us to enhance the cells efficiency up to almost 19%. So far, this is the best known result for this particular perovskite material with incorporated nanoparticles."

According to the scientists, this is the first study to use silicon nanoparticles for enhancing the light harvesting properties of the absorbing upper layer in a perovskite solar cell. The silicon nanoparticles have already surpassed plasmonic ones, but the scientists hope that a deeper study of the interaction between the nanoparticles and light, as well as their application in perovskite solar cells, will lead to even better results.

"In our research, we used MAPbI3 perovskite, which allowed us to study in detail how resonant silicon nanoparticles affect perovskite solar cells, " said Sergey Makarov, head of ITMO's Laboratory of Hybrid Nanophotonics and Optoelectronics. "Now we can further try to use such particles for other types of perovskites with increased efficiency and stability. Apart from that, the nanoparticles themselves can be modified in order to enhance their optical and transport properties. It is important to note that silicon nanoparticles are very inexpensive and easy to produce. Therefore, this method can be easily incorporated in the process of solar cell production."

This story is adapted from material from ITMO University, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier. Link to original source.