@article{CeymanRosspeintnerSchrecketal.2016,
  author    = {Ceyman, Harald and Rosspeintner, Arnulf and Schreck, Maximilian H. and M{\"u}tzel, Carina and Stoy, Andreas and Vauthey, Eric and Lambert, Christoph},
  title     = {Cooperative enhancement versus additivity of two-photon-absorption cross sections in linear and branched squaraine superchromophores},
  series = {Physical Chemistry Chemical Physics},
  volume    = {18},
  journal   = {Physical Chemistry Chemical Physics},
  number    = {24},
  doi       = {10.1039/c6cp02312f},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-188299},
  pages     = {16404-16413},
  year      = {2016},
  abstract  = {The linear and nonlinear optical properties of a series of oligomeric squaraine dyes were investigated by one-photon absorption spectroscopy (1PA) and two-photon absorption (2PA) induced fluorescence spectroscopy. The superchromophores are based on two indolenine squaraine dyes with transoid (SQA) and cisoid configuration (SQB). Using these monomers, linear dimers and trimers as well as star-shaped trimers and hexamers with benzene or triphenylamine cores were synthesised and investigated. The red-shifted and intensified 1PA spectra of all superchromophores could well be explained by exciton coupling theory. In the linear chromophore arrangements we also found superradiance of fluorescence but not in the branched systems. Furthermore, the 2PA showed enhanced cross sections for the linear oligomers but only additivity for the branched systems. This emphasizes that the enhancement of the 2PA cross section in the linear arrangements is probably caused by orbital interactions of higher excited configurations.},
  language  = {en}
}
@article{HarkinBrochSchrecketal.2016,
  author    = {Harkin, David J. and Broch, Katharina and Schreck, Maximilian and Ceyman, Harald and Stoy, Andreas and Yong, Chaw-Keong and Nikolka, Mark and McCulloch, Ian and Stingelin, Natalie and Lambert, Christoph and Sirringhaus, Henning},
  title     = {Decoupling charge transport and electroluminescence in a high mobility polymer semiconductor},
  series = {Advanced Materials},
  volume    = {28},
  journal   = {Advanced Materials},
  number    = {30},
  doi       = {10.1002/adma.201600851},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-187670},
  pages     = {6378-6285},
  year      = {2016},
  abstract  = {Fluorescence enhancement of a high-mobility polymer semiconductor is achieved via energy transfer to a higher fluorescence quantum yield squaraine dye molecule on 50 ps timescales. In organic light-emitting diodes, an order of magnitude enhancement of the external quantum efficiency is observed without reduction in the charge-carrier mobility resulting in radiances of up to 5 W str\(^{-1}\) m\(^{-2}\) at 800 nm.},
  language  = {en}
}