TY  - GEN
A1  - Faßl, Paul
Y1  - 2019///
TI  - Exploration of Properties, Stability and
Reproducibility of Perovskite Solar Cells
N2  - The first part of this thesis was aimed at understanding the role of microstructure in
the material degradation rate of polycrystalline methylammonium lead iodide perovskite
(MAPbI3) films under controlled exposure to oxygen and simulated sunlight. It was ascertained
that MAPbI3 films consisting of small and irregularly ordered crystal grains degrade
much more rapidly when compared to films consisting of large, regularly ordered
grains. Microstructural analysis revealed that the degradation rate varies widely across a
film and commences at the grain boundaries, which suggests that degradation in MAPbI3
films stems from a spatially varying density of defects. The second part of this thesis aimed
at understanding reproducibility issues by exploring the effect of fractional variations in
the precursor solution stoichiometry, which is used for MAPbI3 film fabrication. Despite
only minor changes in microstructure, such variations showed a strong effect on the surface
composition and energetics of MAPbI3 films, as well as the photovoltaic parameters and
stability of solar cell devices. Steady-state and time-resolved photoluminescence measurements under various atmospheres revealed strong heterogeneities in the material properties depending on the exact stoichiometry. Taken together, these results reveal the low tolerance
of perovskite materials towards oxygen exposure, as well as towards small variations in precursor stoichiometry, and partly explain the discrepancies and irreproducibility commonly encountered in perovskite research.
ID  - heidok25787
AV  - public
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/25787/
KW  - perovskite
KW  -  solar cells
KW  -  semiconductors
KW  -  degradation
KW  -  stability
KW  -  oxygen
KW  -  stoichiometry
KW  -  reproducibility
ER  -