ACS Nano http://doi.org/94q (2015)

The central component of a solar cell is the absorber layer, and the more photons that can hit this layer, the more power the cell will generate. However, regardless of its intrinsic absorption ability, the efficiency of a solar panel will deteriorate over time due to the accumulation of dust and dirt on its surface. Kun-Yu Lai, Jr-Hau He and colleagues from KAUST and the National Central University in Taiwan have now developed high-efficiency silicon solar cells that offer excellent self-cleaning capabilities.

The researchers enhanced the performance and lifetime of the cells by covering the devices with nanostructured packaging glass. In particular, hierarchical nanostructures were created on the surface of the glass by combining large honeycomb nanowalls with ultrathin nanorods. The dimensions of these structures were specifically selected to maximize the overall light absorption efficiency: the nanorods serve to reduce the surface reflectance and facilitate light penetration into the cell; the honeycomb structures enhance photon absorption by acting as effective scattering centres. Furthermore, due to its extreme hydrophobicity, the nanostructured packaging glass efficiently repels dust particles, preventing drops in efficiency over time.