@article{AlbrechtSchaeferLangeetal.2012,
  author    = {Albrecht, Steve and Schaefer, Sebastian and Lange, Ilja and Yilmaz, Seyfullah and Dumsch, Ines and Allard, Sybille and Scherf, Ullrich and Hertwig, Andreas and Neher, Dieter},
  title     = {Light management in PCPDTBT:PC70BM solar cells: A comparison of standard and inverted device structures},
  series = {Organic electronics : physics, materials and applications},
  volume    = {13},
  journal   = {Organic electronics : physics, materials and applications},
  number    = {4},
  publisher = {Elsevier},
  address   = {Amsterdam},
  issn      = {1566-1199},
  doi       = {10.1016/j.orgel.2011.12.019},
  pages     = {615 -- 622},
  year      = {2012},
  abstract  = {We compare standard and inverted bulk heterojunction solar cells composed of PCPDTBT:PC70BM blends. Inverted devices comprising 100 nm thick active layers exhibited short circuit currents of 15 mA/cm(2), 10\% larger than in corresponding standard devices. Modeling of the optical field distribution in the different device stacks proved that this enhancement originates from an increased absorption of incident light in the active layer. Internal quantum efficiencies (IQEs) were obtained from the direct comparison of experimentally derived and modeled currents for different layer thicknesses, yielding IQEs of similar to 70\% for a layer thickness of 100 nm. Simulations predict a significant increase of the light harvesting efficiency upon increasing the layer thickness to 270 nm. However, a continuous deterioration of the photovoltaic properties with layer thickness was measured for both device architectures, attributed to incomplete charge extraction. On the other hand, our optical modeling suggests that inverted devices based on PCPDTBT should be able to deliver high power conversion efficiencies (PCEs) of more than 7\% provided that recombination losses can be reduced.},
  language  = {en}
}
@article{SchickHerzogBojahretal.2014,
  author    = {Schick, Daniel and Herzog, Marc and Bojahr, Andre and Leitenberger, Wolfram and Hertwig, Andreas and Shayduk, Roman and Bargheer, Matias},
  title     = {Ultrafast lattice response of photoexcited thin films studied by X-ray diffraction},
  series = {Structural dynamics},
  volume    = {1},
  journal   = {Structural dynamics},
  number    = {6},
  publisher = {American Institute of Physics},
  address   = {Melville},
  issn      = {2329-7778},
  doi       = {10.1063/1.4901228},
  pages     = {13},
  year      = {2014},
  abstract  = {Using ultrafast X-ray diffraction, we study the coherent picosecond lattice dynamics of photoexcited thin films in the two limiting cases, where the photoinduced stress profile decays on a length scale larger and smaller than the film thickness. We solve a unifying analytical model of the strain propagation for acoustic impedance-matched opaque films on a semi-infinite transparent substrate, showing that the lattice dynamics essentially depend on two parameters: One for the spatial profile and one for the amplitude of the strain. We illustrate the results by comparison with high-quality ultrafast X-ray diffraction data of SrRuO3 films on SrTiO3 substrates. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.},
  language  = {en}
}