TY - UNPB

T1 - Microcrystals as amplifiers to learn about the facet- and point de-fect-dependent lability and stabilization of hybrid perovskite semi-conductors against humidity and light

AU - Bahnmüller, Ulrich

AU - Krysiak, Yasar

AU - Locmelis, Sonja

AU - Polarz, Sebastian

N1 - Funding Information: This research was funded by the Deutsche Forschungsgemeinschaft (DFG), SPP2196 (Perovskite semiconductors: From fundamental properties to devices). Acknowledgments: The authors thank the LNQE research center for access to the TEM. The authors thank Armin Feldhoff for access to the SEM. We acknowledge the use of the equipment and the expert support usage and data analysis provided by cfMATCH.

PY - 2022/4/27

Y1 - 2022/4/27

N2 - Shape-controlled methyl ammonium lead bromide microcrystals are used to unravel the facet-selective differences in the reac-tivity of hybrid perovskite semiconductors against chemical and physical triggers. The microstructure of thin films made of hybrid perovskitesis highly dynamic because it is prone to small deviations in external conditions, e.g. the presence of traces of water. During operation in photo-voltaics, even the exposure to light or the infusion of heat can induce unpredictable changes. Because such films consist of irregular microcrys-talline domains fused together, it is very hard to study the mentioned processes directly. The investigation of isolated microcrystals as modelscan solve this problem. Herein, two types of well-defined CH3NH3PbBr3 microcrystals are compared to each other, one with cubic shapeterminated by (100) facets, the other with rhombododecahedral shape and exclusively (110) facets. Those microcrystals amplify the sensitiv-ity of hybrid perovskites against humidity, against irradiation or to heat. The surfaces of the cubic particles are thermodynamically more sta-ble, but their reactivity is much higher. Although chemically equivalent, rhombodocecahedral microcrystals are much more stable. However,it is demonstrated that cubic microcrystals are significantly less labile, when a small fraction of CH3NH3+ is substituted by Cs+.

AB - Shape-controlled methyl ammonium lead bromide microcrystals are used to unravel the facet-selective differences in the reac-tivity of hybrid perovskite semiconductors against chemical and physical triggers. The microstructure of thin films made of hybrid perovskitesis highly dynamic because it is prone to small deviations in external conditions, e.g. the presence of traces of water. During operation in photo-voltaics, even the exposure to light or the infusion of heat can induce unpredictable changes. Because such films consist of irregular microcrys-talline domains fused together, it is very hard to study the mentioned processes directly. The investigation of isolated microcrystals as modelscan solve this problem. Herein, two types of well-defined CH3NH3PbBr3 microcrystals are compared to each other, one with cubic shapeterminated by (100) facets, the other with rhombododecahedral shape and exclusively (110) facets. Those microcrystals amplify the sensitiv-ity of hybrid perovskites against humidity, against irradiation or to heat. The surfaces of the cubic particles are thermodynamically more sta-ble, but their reactivity is much higher. Although chemically equivalent, rhombodocecahedral microcrystals are much more stable. However,it is demonstrated that cubic microcrystals are significantly less labile, when a small fraction of CH3NH3+ is substituted by Cs+.

U2 - 10.26434/chemrxiv-2022-gq8vj

DO - 10.26434/chemrxiv-2022-gq8vj

M3 - Working paper/Discussion paper

BT - Microcrystals as amplifiers to learn about the facet- and point de-fect-dependent lability and stabilization of hybrid perovskite semi-conductors against humidity and light

ER -