10.1137/18M1207272
Friesecke, Gero
Gero
Friesecke
Kniely, Michael
Michael
Kniely0000-0001-5645-4333
New optimal control problems in density functional theory motivated by photovoltaics
SIAM
2019
2019-08-04T21:59:21Z
2019-11-14T08:43:38Z
journal_article
/record/6762
/record/6762.json
15403459
1808.04200
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.