@article{KimLiessStolteetal.2021,
  author    = {Kim, Jin Hong and Liess, Andreas and Stolte, Matthias and Krause, Ana-Maria and Stepanenko, Vladimir and Zhong, Chuwei and Bialas, David and Spano, Frank and W{\"u}rthner, Frank},
  title     = {An Efficient Narrowband Near-Infrared at 1040 nm Organic Photodetector Realized by Intermolecular Charge Transfer Mediated Coupling Based on a Squaraine Dye},
  series = {Advanced Materials},
  volume    = {33},
  journal   = {Advanced Materials},
  number    = {26},
  doi       = {10.1002/adma.202100582},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-256374},
  year      = {2021},
  abstract  = {A highly sensitive short-wave infrared (SWIR, λ > 1000 nm) organic photodiode (OPD) is described based on a well-organized nanocrystalline bulk-heterojunction (BHJ) active layer composed of a dicyanovinyl-functionalized squaraine dye (SQ-H) donor material in combination with PC\(_{61}\)BM. Through thermal annealing, dipolar SQ-H chromophores self-assemble in a nanoscale structure with intermolecular charge transfer mediated coupling, resulting in a redshifted and narrow absorption band at 1040 nm as well as enhanced charge carrier mobility. The optimized OPD exhibits an external quantum efficiency (EQE) of 12.3\% and a full-width at half-maximum of only 85 nm (815 cm\(^{-1}\)) at 1050 nm under 0 V, which is the first efficient SWIR OPD based on J-type aggregates. Photoplethysmography application for heart-rate monitoring is successfully demonstrated on flexible substrates without applying reverse bias, indicating the potential of OPDs based on short-range coupled dye aggregates for low-power operating wearable applications.},
  language  = {en}
}
@article{KimSchembriBialasetal.2022,
  author    = {Kim, Jin Hong and Schembri, Tim and Bialas, David and Stolte, Matthias and W{\"u}rthner, Frank},
  title     = {Slip-Stacked J-Aggregate Materials for Organic Solar Cells and Photodetectors},
  series = {Advanced Materials},
  volume    = {34},
  journal   = {Advanced Materials},
  number    = {22},
  doi       = {10.1002/adma.202104678},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-276537},
  year      = {2022},
  abstract  = {Dye-dye interactions affect the optical and electronic properties in organic semiconductor films of light harvesting and detecting optoelectronic applications. This review elaborates how to tailor these properties of organic semiconductors for organic solar cells (OSCs) and organic photodiodes (OPDs). While these devices rely on similar materials, the demands for their optical properties are rather different, the former requiring a broad absorption spectrum spanning from the UV over visible up to the near-infrared region and the latter an ultra-narrow absorption spectrum at a specific, targeted wavelength. In order to design organic semiconductors satisfying these demands, fundamental insights on the relationship of optical properties are provided depending on molecular packing arrangement and the resultant electronic coupling thereof. Based on recent advancements in the theoretical understanding of intermolecular interactions between slip-stacked dyes, distinguishing classical J-aggregates with predominant long-range Coulomb coupling from charge transfer (CT)-mediated or -coupled J-aggregates, whose red-shifts are primarily governed by short-range orbital interactions, is suggested. Within this framework, the relationship between aggregate structure and functional properties of representative classes of dye aggregates is analyzed for the most advanced OSCs and wavelength-selective OPDs, providing important insights into the rational design of thin-film optoelectronic materials.},
  language  = {en}
}