Regensburg 2019 – wissenschaftliches Programm
HL 45.6: Poster
Donnerstag, 4. April 2019, 18:30–21:00, Poster E
Reversible changes of the bandgap energy in multiple-cation mixed-halide perovskite solar cells under illumination and bias investigated by optical spectroscopy — •Eva Wirth1, Fabian Ruf1, Meltem F. Aygüler2, Jonas Hanisch3, Pablo Docampo4, Erik Ahlswede3, Heinz Kalt1 und Michael Hetterich1,5 — 1Institute of Applied Physics, Karlsruhe Institute of Technology (KIT), Karlsruhe, Germany — 2Dept. of Chemistry and CeNS, LMU Munich, München, Germany — 3Zentrum für Sonnenenergie- und Wasserstoff-Forschung Baden-Württemberg (ZSW), Stuttgart, Germany — 4Physics Dept., School of Electrical and Electronic Engineering, Newcastle University, Newcastle upon Tyne, United Kingdom — 5Light Technology Institute, KIT, Karlsruhe, Germany
Perovskite solar cells (PSC) provide a wide-range bandgap tunability (by intermixing of different ions) enabling the fabrication of tandem cells. But the stability of mixed PSC is still problematic. We investigate compositional instabilities and resulting shifts of the bandgap energy of these compounds non-destructively using electroreflectance spectroscopy. Thereby the relative change of the reflectance ΔR/R is analyzed. Under illumination as well as varying relative humidity and applied voltage, shifts of the bandgap are observed. The latter are caused by segregation effects in the Br–I system, which are partly reversible. We compare PSC with different absorber materials in order to reveal the influence of different architectures. To study the halide segregation in more detail, we apply TOF-SIMS measurements.