title: Hexagonal transition-metal chalcogenide nanoflakes with pronounced lateral quantum confinement.
abstract: Transition-metal chalcogenide (TMC) nanoflakes of composition MX2 (where M=Ti, Zr and Hf; X=S and Se) crystallize preferentially in equilateral hexagons and exhibit a pronounced lateral quantum confinement. The hexagonal shape of octahedral (1T) TMC nanoflakes is the result of charge localization at the edges/vertices and the resulting Coulomb repulsion. Independent of their size, all nanoflakes have the Mn X2n-2 stoichiometry and thus an unoxidized metal center which results in dopant states. These states become relevant for small nanoflakes and lead to metallic character, but for larger nanoflakes (>6 nm) the 2D monolayer properties dominate. Finally, coordination of Lewis bases at the nanoflake edges has no significant effect on the electronic structure of these species confirming the viability of colloidal synthetic approaches.
authors.affiliation: School of Engineering and Science, Jacobs University Bremen, Campus Ring 1, 28759 Bremen (Germany). p.miro@jacobs-university.de.
authors.forename: Pere
authors.initials: P
authors.lastname: Miró
authors.forename: Jae Hyo
authors.initials: JH
authors.lastname: Han
authors.forename: Jinwoo
authors.initials: J
authors.lastname: Cheon
authors.forename: Thomas
authors.initials: T
authors.lastname: Heine
keywords: 2D materials; density functional theory; nanoflakes; quantum confinement; transition-metal chalcogenide