Efficient light trapping in ultrathin-crystalline-silicon solar cells using TiO2 nanosphere arrays

Ultrathin-crystalline-silicon solar cell is important for its low cost and flexibility, but its efficiency is low. Light trapping technology is a useful way to improve the efficiency. In this paper, we design a TiO₂ nanosphere arrays on the top of the ultrathin-crystalline-silicon solar cells with 2-μm-thickness to achieve advanced light trapping property. The finite element method is used to study the optical properties of the sphere nanostructure on the ultrathin-crystalline-silicon solar cells. The light trapping ability is systematically studied by COMSOL multiphysics. The results show that the sphere nanostructure can highly increase the light absorption of the ultrathin-crystalline-silicon in the wavelengths from 300 to 1200 nm. The average absorption rate increases by 58.63% compared to 2-μm-thick crystalline silicon.