A paste made out of titanium dioxide and resonant silicon nanoparticles enabled researchers from Russia and Italy to achieve 21.1% power conversion efficiency for halide (MAPbl3) perovskite solar cells under a project supported by a grant from the Russian Science Foundation.
The ITMO School of Physics and Engineering in Russia and Tor Vergata University of Rome, Italy used the nanoparticle paste with Mie-resonant particles, as an additional layer in perovskite solar cell production, just after the perovskite layer to ensure it is closer to the light source and work as antennae. They observed Mie-resonant particles in the paste were able to control the amount of light absorbed, thereby increasing photocurrent generation to achieve the efficiency level.
They used silicon for their production process to increase light absorption, instead of expensive process of improving the charge collection which would have required use of complex composition and rare metals, driving up its cost.
"We can obtain silicon from sand, so there is almost an endless supply of this material," explained ITMO's School of Physics and Engineering Professor Sergey Makarov. "It would've been a strange solution to simply introduce silicon into the perovskite structure, but it could be introduced as a nanoparticle. Such particles serve as nanoantennae – they catch light and it resonates inside them."
The team figured that while the cost of perovskite solar cell with this production process can increase by only 0.3%, the nanoparticle paste can be used with solar cells of any composition and configuration. It can also be deployed for production of devices as photodetectors, harvesters and optoelectronics.
According to the researchers, the trick is to have exact calculations accounting for electrophysical and optical properties of all layers and nanoparticles for the paste to work as desired.
Their work has found its place in the scientific journal called Nano Energy titled Mie-resonant mesoporous electron transport layer for highly efficient perovskite solar cells.