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@ARTICLE{Siekmann:894638,
      author       = {Siekmann, Johanna and Ravishankar, Sandheep and Kirchartz,
                      Thomas},
      title        = {{A}pparent {D}efect {D}ensities in {H}alide {P}erovskite
                      {T}hin {F}ilms and {S}ingle {C}rystals},
      journal      = {ACS energy letters},
      volume       = {6},
      number       = {9},
      issn         = {2380-8195},
      address      = {Washington, DC},
      publisher    = {American Chemical Society},
      reportid     = {FZJ-2021-03334},
      pages        = {3244 - 3251},
      year         = {2021},
      abstract     = {Non-radiative recombination via defects is a major loss
                      mechanism for nearly all photovoltaic technologies. (1)
                      Despite their frequently quoted “defect tolerance”,
                      (2,3) halide perovskites are no exception to this rule,
                      given that it remains difficult to exceed luminescence
                      quantum efficiencies of a few percent at photovoltaic
                      working conditions in devices. (4−6) Given the importance
                      of non-radiative recombination, the experimental detection
                      of the culprits, i.e., the most recombination-active
                      defects, is of substantial importance for controlled
                      optimization of devices but also for long-term strategic
                      decisions. One such strategic decision is the assessment of
                      possible performance benefits associated with going from
                      polycrystalline thin films to single crystals (7,8) as
                      active elements in perovskite solar cells. A substantial
                      amount of experimental data (9−17) indicates that
                      polycrystalline thin films of lead halide perovskites
                      typically have defect densities on the order of 1015–1016
                      cm–3, while single crystals are typically reported
                      (9,14,18−20) to have bulk defect densities of 1012 cm–3
                      or lower. These findings support an intuitive rationale,
                      namely that single crystals have orders of magnitude lower
                      defect densities than thin films that should contain a
                      certain density of defects at their grain boundaries. This
                      narrative has even inspired paper titles such as the one
                      from Brenes et al., (21) who write about “Metal Halide
                      Perovskite Polycrystalline Films Exhibiting Properties of
                      Single Crystals” while reporting exceptionally long
                      charge-carrier lifetimes in perovskite thin films.},
      cin          = {IEK-5},
      ddc          = {333.7},
      cid          = {I:(DE-Juel1)IEK-5-20101013},
      pnm          = {1215 - Simulations, Theory, Optics, and Analytics (STOA)
                      (POF4-121)},
      pid          = {G:(DE-HGF)POF4-1215},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000696180500026},
      doi          = {10.1021/acsenergylett.1c01449},
      url          = {https://juser.fz-juelich.de/record/894638},
}