title: Highly Emissive Divalent-Ion-Doped Colloidal CsPb1-xMxBr3Perovskite Nanocrystals through Cation Exchange.
abstract: Colloidal CsPbX3(X = Br, Cl, and I) perovskite nanocrystals (NCs) have emerged as promising phosphors and solar cell materials due to their remarkable optoelectronic properties. These properties can be tailored by not only controlling the size and shape of the NCs but also postsynthetic composition tuning through topotactic anion exchange. In contrast, property control by cation exchange is still underdeveloped for colloidal CsPbX3NCs. Here, we present a method that allows partial cation exchange in colloidal CsPbBr3NCs, whereby Pb2+is exchanged for several isovalent cations, resulting in doped CsPb1-xMxBr3NCs (M= Sn2+, Cd2+, and Zn2+; 0 < x ≤ 0.1), with preservation of the original NC shape. The size of the parent NCs is also preserved in the product NCs, apart from a small (few %) contraction of the unit cells upon incorporation of the guest cations. The partial Pb2+for M2+exchange leads to a blue-shift of the optical spectra, while maintaining the high photoluminescence quantum yields (>50%), sharp absorption features, and narrow emission of the parent CsPbBr3NCs. The blue-shift in the optical spectra is attributed to the lattice contraction that accompanies the Pb2+for M2+cation exchange and is observed to scale linearly with the lattice contraction. This work opens up new possibilities to engineer the properties of halide perovskite NCs, which to date are demonstrated to be the only known system where cation and anion exchange reactions can be sequentially combined while preserving the original NC shape, resulting in compositionally diverse perovskite NCs.
authors.affiliation: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508 TA Utrecht, The Netherlands.
authors.forename: Ward
authors.initials: W
authors.lastname: van der Stam
authors.affiliation: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508 TA Utrecht, The Netherlands.
authors.forename: Jaco J
authors.initials: JJ
authors.lastname: Geuchies
authors.affiliation: EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Thomas
authors.initials: T
authors.lastname: Altantzis
authors.affiliation: EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Karel H W
authors.initials: KH
authors.lastname: van den Bos
authors.affiliation: Electron Microscopy Utrecht, Utrecht University , 3584 CH Utrecht, The Netherlands.
authors.forename: Johannes D
authors.initials: JD
authors.lastname: Meeldijk
authors.affiliation: EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Sandra
authors.initials: S
authors.lastname: Van Aert
authors.affiliation: EMAT, University of Antwerp , Groenenborgerlaan 171, B-2020 Antwerp, Belgium.
authors.forename: Sara
authors.identifier: 0000-0002-4249-8017
authors.initials: S
authors.lastname: Bals
authors.affiliation: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508 TA Utrecht, The Netherlands.
authors.forename: Daniel
authors.identifier: 0000-0002-3535-8366
authors.initials: D
authors.lastname: Vanmaekelbergh
authors.affiliation: Condensed Matter and Interfaces, Debye Institute for Nanomaterials Science, Utrecht University , P.O. Box 80000, 3508 TA Utrecht, The Netherlands.
authors.forename: Celso
authors.identifier: 0000-0002-4403-3627
authors.initials: C
authors.lastname: de Mello Donega