Hybrid silicon–carbon nanostructures for broadband optical absorption

摘要

Proper design of nanomaterials for broadband light absorption is a key factor for improving the conversion efficiency of solar cells. Here we present a hybrid design of silicon–carbon nanostructures with silicon clusters coated by carbon cages, i.e., Si_m@C_2n for potential solar cell application. The optical properties of these hybrid nanostructures were calculated based on time dependent density function theory (TDDFT). The results show that the optical spectra of Si_m@C_2n are very different from those of pure Si_m and C_2n clusters. While the absorption spectra of pure carbon cages and Si_m clusters exhibit peaks in the UV region, those of the Si_m@C_2n nanostructures exhibit a significant red shift. Superposition of the optical spectra of various Si_m@C_2n nanostructures forms a broad-band absorption, which extends to the visible light and infrared regions. The broadband adsorption of the assembled Si_m@C_2n nanoclusters may provide a new approach for the design of high efficiency solar cell nanomaterials.