TY  - JOUR
A1  - Cappel, Ute B.
A1  - Svanstrom, Sebastian
A1  - Lanzilotto, Valeria
A1  - Johansson, Fredrik O. L.
A1  - Aitola, Kerttu
A1  - Philippe, Bertrand
A1  - Giangrisostomi, Erika
A1  - Ovsyannikov, Ruslan
A1  - Leitner, Torsten
A1  - Föhlisch, Alexander
A1  - Svensson, Svante
A1  - Martensson, Nils
A1  - Boschloo, Gerrit
A1  - Lindblad, Andreas
A1  - Rensmo, Hakan
T1  - Partially Reversible Photoinduced Chemical Changes in a Mixed-Ion Perovskite Material for Solar Cells
JF  - ACS applied materials & interfaces
N2  - Metal halide perovskites have emerged as materials of high interest for solar energy-to-electricity conversion, and in particular, the use of mixed-ion structures has led to high power conversion efficiencies and improved stability. For this reason, it is important to develop means to obtain atomic level understanding of the photoinduced behavior of these materials including processes such as photoinduced phase separation and ion migration. In this paper, we implement a new methodology combining visible laser illumination of a mixed-ion perovskite ((FAP-bI(3))(0.85)(MAPbBr(3))(0.15)) with the element specificity and chemical sensitivity of core-level photoelectron spectroscopy. By carrying out measurements at a synchrotron beamline optimized for low X-ray fluxes, we are able to avoid sample changes due to X-ray illumination and are therefore able to monitor what sample changes are induced by visible illumination only. We find that laser illumination causes partially reversible chemistry in the surface region, including enrichment of bromide at the surface, which could be related to a phase separation into bromide- and iodide-rich phases. We also observe a partially reversible formation of metallic lead in the perovskite structure. These processes occur on the time scale of minutes during illumination. The presented methodology has a large potential for understanding light-induced chemistry in photoactive materials and could specifically be extended to systematically study the impact of morphology and composition on the photostability of metal halide perovskites.
KW  - photoelectron spectroscopy
KW  - laser illumination
KW  - lead halide perovskite
KW  - ion migration
KW  - phase separation
KW  - stability
Y1  - 2017
U6  - https://doi.org/10.1021/acsami.7b10643
SN  - 1944-8244
VL  - 9
SP  - 34970
EP  - 34978
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - JOUR
A1  - Zehbe, Kerstin
A1  - Kollosche, Matthias
A1  - Lardong, Sebastian
A1  - Kelling, Alexandra
A1  - Schilde, Uwe
A1  - Taubert, Andreas
T1  - Ionogels Based on Poly(methyl methacrylate) and Metal-Containing Ionic Liquids: Correlation between Structure and Mechanical and Electrical Properties
JF  - International journal of molecular sciences
N2  - Ionogels (IGs) based on poly(methyl methacrylate) (PMMA) and the metal-containing ionic liquids (ILs) bis-1-butyl-3-methlimidazolium tetrachloridocuprate(II), tetrachloride cobaltate(II), and tetrachlorido manganate(II) have been synthesized and their mechanical and electrical properties have been correlated with their microstructure. Unlike many previous examples, the current IGs show a decreasing stability in stress-strain experiments on increasing IL fractions. The conductivities of the current IGs are lower than those observed in similar examples in the literature. Both effects are caused by a two-phase structure with micrometer-sized IL-rich domains homogeneously dispersed an IL-deficient continuous PMMA phase. This study demonstrates that the IL-polymer miscibility and the morphology of the IGs are key parameters to control the (macroscopic) properties of IGs.
KW  - microstructure
KW  - ionogels
KW  - ionic liquids
KW  - phase separation
KW  - mechanical properties
KW  - ionic conductivity
Y1  - 2016
U6  - https://doi.org/10.3390/ijms17030391
SN  - 1422-0067
VL  - 17
PB  - MDPI
CY  - Basel
ER  -