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

• DOI: 10.1002/anie.202205617
• Publication Date: 2022-06-24T11:01:58Z
• Authors: Clara Otero‐Martínez; Muhammad Imran; Nadine J. Schrenker; Junzhi Ye; Kangyu Ji; Akshay Rao; Samuel D. Stranks; Robert L. Z. Hoye; Sara Bals; Liberato Manna; Jorge Pérez‐Juste; Lakshminarayana P...
• Keywords: Formamidinium

We report here fast A-site cation cross-exchange between APbX3 perovskite nanocrystals (NCs) made of different A-cations (Cs (cesium), FA (formamidinium), and MA (methylammonium)) at room temperature. Surprisingly, the A-cation proceeds as halide (X=Cl, Br, or I) exchange with help free A-oleate complexes present in freshly prepared colloidal NC solutions. This enabled preparation double (MACs, MAFA, CsFA)- triple (MACsFA)-cation NCs an optical band gap that is finely tunable by their composition. The spectroscopy together structural analysis using XRD atomically resolved high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) integrated differential phase contrast (iDPC) STEM indicates homogeneous distribution cations mixed lattice. Unlike ions, do not phase-segregate under light illumination.