@article{BaumannTvingstedtHeiberetal.2014,
  author    = {Baumann, A. and Tvingstedt, K. and Heiber, M. C. and V{\"a}th, S. and Momblona, C. and Bolink, H. J. and Dyakonov, V.},
  title     = {Persistent photovoltage in methylammonium lead iodide perovskite solar cells},
  series = {APL Materials},
  volume    = {2},
  journal   = {APL Materials},
  number    = {8},
  doi       = {10.1063/1.4885255},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119397},
  pages     = {081501},
  year      = {2014},
  abstract  = {We herein perform open circuit voltage decay (OCVD) measurements on methylammonium lead iodide (CH3NH3PbI3) perovskite solar cells to increase the understanding of the charge carrier recombination dynamics in this emerging technology. Optically pulsed OCVD measurements are conducted on CH3NH3PbI3 solar cells and compared to results from another type of thin-film photovoltaics, namely, the two reference polymer-fullerene bulk heterojunction solar cell devices based on P3HT:PC60BM and PTB7:PC70BM blends. We observe two very different time domains of the voltage transient in the perovskite solar cell with a first drop on a short time scale that is similar to the decay in the studied organic solar cells. However, 65\%-70\% of the maximum photovoltage persists on much longer timescales in the perovskite solar cell than in the organic devices. In addition, we find that the recombination dynamics in all time regimes are dependent on the starting illumination intensity, which is also not observed in the organic devices. We then discuss the potential origins of these unique behaviors.},
  language  = {en}
}
@article{TvingstedtMalinkiewiczBaumannetal.2014,
  author    = {Tvingstedt, Kristofer and Malinkiewicz, Olga and Baumann, Andreas and Deibel, Carsten and Snaith, Henry J. and Dyakonov, Vladimir and Bolink, Henk J.},
  title     = {Radiative efficiency of lead iodide based perovskite solar cells},
  series = {Scientific Reports},
  volume    = {4},
  journal   = {Scientific Reports},
  doi       = {10.1038/srep06071},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-119360},
  pages     = {6071},
  year      = {2014},
  abstract  = {The maximum efficiency of any solar cell can be evaluated in terms of its corresponding ability to emit light. We herein determine the important figure of merit of radiative efficiency for Methylammonium Lead Iodide perovskite solar cells and, to put in context, relate it to an organic photovoltaic (OPV) model device. We evaluate the reciprocity relation between electroluminescence and photovoltaic quantum efficiency and conclude that the emission from the perovskite devices is dominated by a sharp band-to-band transition that has a radiative efficiency much higher than that of an average OPV device. As a consequence, the perovskite have the benefit of retaining an open circuit voltage ~0.14 V closer to its radiative limit than the OPV cell. Additionally, and in contrast to OPVs, we show that the photoluminescence of the perovskite solar cell is substantially quenched under short circuit conditions in accordance with how an ideal photovoltaic cell should operate.},
  language  = {en}
}