Fast A‐Site Cation Cross‐Exchange at Room Temperature: Single‐to Double‐ and Triple‐Cation Halide Perovskite Nanocrystals

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Otero‐Martínez, Clara 
Schrenker, Nadine J 
Ye, Junzhi 
Ji, Kangyu 

jats:titleAbstract</jats:title>jats:pWe report here fast A‐site cation cross‐exchange between APbXjats:sub3</jats:sub> perovskite nanocrystals (NCs) made of different A‐cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A‐cation cross‐exchange proceeds as fast as the halide (X=Cl, Br, or I) exchange with the help of free A‐oleate complexes present in the freshly prepared colloidal perovskite NC solutions. This enabled the preparation of double (MACs, MAFA, CsFA)‐ and triple (MACsFA)‐cation perovskite NCs with an optical band gap that is finely tunable by their A‐site composition. The optical spectroscopy together with structural analysis using XRD and atomically resolved high‐angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) and integrated differential phase contrast (iDPC) STEM indicates the homogeneous distribution of different cations in the mixed perovskite NC lattice. Unlike halide ions, the A‐cations do not phase‐segregate under light illumination.</jats:p>


Funder: Royal Society; Id:

34 Chemical Sciences, 3406 Physical Chemistry
Journal Title
Angewandte Chemie
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European Research Council (756962)
Engineering and Physical Sciences Research Council (EP/R023980/1)