Optical Tamm states enhanced broad-band absorption of organic solar cells

We present a design concept of thin-film organic solar cells using a photonic crystal as the electrode. Through the excitation of optical Tamm states (OTSs), the proposed photonic crystal based organic solar cells (PC-OSCs) exhibit a broad-band absorption enhancement owing to the abnormal refractive index variation of the active layer. The overall absorptivity can be increased by similar to 35% compared with that of the optimized conventional planar OSC. Remarkably, our easily manufactured planar PC-OSC exhibits almost the same overall absorptivity as the optimized conventional corrugated OSC. The excellent performance comes from the achievement of OTS for both transverse-magnetic and transverse-electric polarized enhanced absorption. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.4770316]