Metallic nanoparticles as intermediate reflectors in tandem solar cells

Tandem thin film solar cells made of amorphous and microcrystalline silicon offer the potential for high conversion efficiencies at low costs. However, their finite thickness imposed by intrinsic materials properties hinders the complete absorption of light and requires smart photon management. We reveal a genuine strategy to use metallic nanoparticles, appropriately tailored to provide a spectrally selective reflection, as an intermediate reflector. It enhances foremost light absorption in the top cell. We show that the current density for an optimized cell can be 1.16 times larger when compared to a cell without a spectrally selective intermediate reflector. (C) 2009 American Institute of Physics. [doi:10.1063/1.3232230]