@article{6762,
  abstract     = {We present and study novel optimal control problems motivated by the search for photovoltaic materials with high power-conversion efficiency. The material must perform the first step: convert light (photons) into electronic excitations. We formulate various desirable properties of the excitations as mathematical control goals at the Kohn-Sham-DFT level
of theory, with the control being given by the nuclear charge distribution. We prove that nuclear distributions exist which give rise to optimal HOMO-LUMO excitations, and present illustrative numerical simulations for 1D finite nanocrystals. We observe pronounced goal-dependent features such as large electron-hole separation, and a hierarchy of length scales: internal HOMO and LUMO wavelengths < atomic spacings < (irregular) fluctuations of the doping profiles < system size.},
  author       = {Friesecke, Gero and Kniely, Michael},
  issn         = {15403467},
  journal      = {Multiscale Modeling and Simulation},
  number       = {3},
  pages        = {926--947},
  publisher    = {SIAM},
  title        = {{New optimal control problems in density functional theory motivated by photovoltaics}},
  doi          = {10.1137/18M1207272},
  volume       = {17},
  year         = {2019},
}