@article{AmthorWeissenseelFischeretal.2014,
  author    = {Amthor, Matthias and Weißenseel, Sebastian and Fischer, Julian and Kamp, Martin and Schneider, Christian and H{\"o}fling, Sven},
  title     = {Electro-optical switching between polariton and cavity lasing in an InGaAs quantum well microcavity},
  doi       = {10.1364/OE.22.031146},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-111130},
  year      = {2014},
  abstract  = {We report on the condensation of microcavity exciton polaritons under optical excitation in a microcavity with four embedded InGaAs quantum wells. The polariton laser is characterized by a distinct nonlinearity in the input-output-characteristics, which is accompanied by a drop of the emission linewidth indicating temporal coherence and a characteristic persisting emission blueshift with increased particle density. The temporal coherence of the device at threshold is underlined by a characteristic drop of the second order coherence function to a value close to 1. Furthermore an external electric field is used to switch between polariton regime, polariton condensate and photon lasing.},
  language  = {en}
}
@article{WeissenseelGottschollBoennighausenetal.2021,
  author    = {Weissenseel, Sebastian and Gottscholl, Andreas and B{\"o}nnighausen, Rebecca and Dyakonov, Vladimir and Sperlich, Andreas},
  title     = {Long-lived spin-polarized intermolecular exciplex states in thermally activated delayed fluorescence-based organic light-emitting diodes},
  series = {Science Advances},
  volume    = {7},
  journal   = {Science Advances},
  number    = {47},
  doi       = {10.1126/sciadv.abj9961},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-265508},
  year      = {2021},
  abstract  = {Spin-spin interactions in organic light-emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) are pivotal because radiative recombination is largely determined by triplet-to-singlet conversion, also called reverse intersystem crossing (RISC). To explore the underlying process, we apply a spin-resonance spectral hole-burning technique to probe electroluminescence. We find that the triplet exciplex states in OLEDs are highly spin-polarized and show that these states can be decoupled from the heterogeneous nuclear environment as a source of spin dephasing and can even be coherently manipulated on a spin-spin relaxation time scale T-2* of 30 ns. Crucially, we obtain the characteristic triplet exciplex spin-lattice relaxation time T-1 in the range of 50 mu s, which far exceeds the RISC time. We conclude that slow spin relaxation rather than RISC is an efficiency-limiting step for intermolecular donor:acceptor systems. Finding TADF emitters with faster spin relaxation will benefit this type of TADF OLEDs.},
  language  = {en}
}
@phdthesis{Weissenseel2022,
  author    = {Weißenseel, Sebastian G{\"u}nter},
  title     = {Spin-Spin Interactions and their Impact on Organic Light-Emitting Devices},
  doi       = {10.25972/OPUS-25745},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-257458},
  school      = {Universit{\"a}t W{\"u}rzburg},
  year      = {2022},
  abstract  = {This work investigates the correlations between spin states and the light emission properties of organic light-emitting diodes (OLEDs), which are based on the principle of thermally activated delayed fluorescence. The spin-spin interactions responsible for this mechanism are investigated in this work using methods based on spin-sensitive electron paramagnetic resonance (EPR). In particular, this method has been applied to electrically driven OLEDs. The magnetic resonance has been detected by electroluminescence, giving this method its name: electroluminescence detected magnetic resonance (ELDMR). Initial investigations on a novel deep blue TADF emitter were performed. Furthermore, the ELDMR method was used in this work to directly detect the spin states in the OLED. These measurements were further underlined by time-resolved experiments such as transient electro- and photoluminescence.},
  subject      = {Elektronenspinresonanz},
  language  = {en}
}
@article{BunzmannKrugmannWeissenseeletal.2021,
  author    = {Bunzmann, Nikolai and Krugmann, Benjamin and Weissenseel, Sebastian and Kudriashova, Liudmila and Ivaniuk, Khrystyna and Stakhira, Pavlo and Cherpak, Vladyslav and Chapran, Marian and Grybauskaite-Kaminskiene, Gintare and Grazulevicius, Juozas Vidas and Dyakonov, Vladimir and Sperlich, Andreas},
  title     = {Spin- and Voltage-Dependent Emission from Intra- and Intermolecular TADF OLEDs},
  series = {Advanced Electronic Materials},
  volume    = {7},
  journal   = {Advanced Electronic Materials},
  number    = {3},
  doi       = {10.1002/aelm.202000702},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-224434},
  year      = {2021},
  abstract  = {Organic light emitting diodes (OLEDs) based on thermally activated delayed fluorescence (TADF) utilize molecular systems with a small energy splitting between singlet and triplet states. This can either be realized in intramolecular charge transfer states of molecules with near-orthogonal donor and acceptor moieties or in intermolecular exciplex states formed between a suitable combination of individual donor and acceptor materials. Here, 4,4′-(9H,9′H-[3,3′-bicarbazole]-9,9′-diyl)bis(3-(trifluoromethyl) benzonitrile) (pCNBCzoCF\(_{3}\)) is investigated, which shows intramolecular TADF but can also form exciplex states in combination with 4,4′,4′′-tris[phenyl(m-tolyl)amino]triphenylamine (m-MTDATA). Orange emitting exciplex-based OLEDs additionally generate a sky-blue emission from the intramolecular emitter with an intensity that can be voltage-controlled. Electroluminescence detected magnetic resonance (ELDMR) is applied to study the thermally activated spin-dependent triplet to singlet up-conversion in operating devices. Thereby, intermediate excited states involved in OLED operation can be investigated and the corresponding activation energy for both, intra- and intermolecular based TADF can be derived. Furthermore, a lower estimate is given for the extent of the triplet wavefunction to be ≥ 1.2 nm. Photoluminescence detected magnetic resonance (PLDMR) reveals the population of molecular triplets in optically excited thin films. Overall, the findings allow to draw a comprehensive picture of the spin-dependent emission from intra- and intermolecular TADF OLEDs.},
  language  = {en}
}