Transparent, near-infrared organic photovoltaic solar cells for window and energy-scavenging applications

We fabricate near-infrared absorbing organic photovoltaics that are highly transparent to visible light. By optimizing near-infrared optical-interference, we demonstrate power efficiencies of 1.3 +/- 0.1% with simultaneous average visible transmission of > 65%. Subsequent incorporation of near-infrared distributed-Bragg-reflector mirrors leads to an increase in the efficiency to 1.7 +/- 0.1%, approaching the 2.4 +/- 0.2% efficiency of the opaque cell, while maintaining high visible-transparency of > 55%. Finally, we demonstrate that a series-integrated array of these transparent cells is capable of powering electronic devices under near-ambient lighting. This architecture suggests strategies for high-efficiency power-generating windows and highlights an application uniquely benefiting from excitonic electronics. (C) 2011 American Institute of Physics. [doi:10.1063/1.3567516]