Nanoantennas for enhanced light trapping in transparent organic solar   cells
  We propose a light-trapping structure offering a significant enhancement of photovoltaic absorption in transparent organic solar cells operating at infrared while the visible light transmission keeps sufficiently high. The main mechanism of light trapping is related with the excitation of collective oscillations of the metal nanoantenna arrays, characterized by advantageous field distribution in the volume of the solar cell. It allows more than triple increase of infrared photovoltaic absorption. 
Pavel M. Voroshilov, Constantin R. Simovski, and Pavel A. Belov
physics.optics