Light absorption plays a key role in photovoltaic devices, especially in thin-film organic solar cells. Here we study the enhancement of optical absorption in a thin organic layer by embedding it into magnetic metamaterials. In a periodic metal-polymeric-metal sandwiched structure, the absorption of transverse magnetic polarized light has been significantly enhanced. The maximum enhancement is around 7 times, which is attributed to the strong local field enhancement in the organic thin film. Importantly, due to the coexistence of large electric resonance and magnetic resonance in magnetic metamaterials, the enhancement of light absorption has been obtained in a broadband from 350nm to 750nm, which is almost twice of that of the conventional plasmonic device and covers the strongest part of the solar spectrum. Moreover, such absorption enhancement is also valid for a wide range of incident angles. We believe that our finding can lead to a variety of important applications in solar cell technology.
© 2015 Optical Society of AmericaPDF Article