TY - JOUR

T1 - Mapping the Atomistic Structure of Graded Core/Shell Colloidal Nanocrystals

AU - Yarema, Maksym

AU - Xing, Yunhua

AU - Lechner, Rainer T.

AU - Ludescher, Lukas

AU - Dordevic, Nikola

AU - Lin, Weyde M.M.

AU - Yarema, Olesya

AU - Wood, Vanessa

PY - 2017/9/15

Y1 - 2017/9/15

N2 - Engineering the compositional gradient for core/shell semiconductor nanocrystals improves their optical properties. To date, however, the structure of graded core/shell nanocrystal emitters has only been qualitatively described. In this paper, we demonstrate an approach to quantify nanocrystal structure, selecting graded Ag-In-Se/ZnSe core/shell nanocrystals as a proof-of-concept material. A combination of multi-energy small-angle X-ray scattering and electron microscopy techniques enables us to establish the radial distribution of ZnSe with sub-nanometer resolution. Using ab initio shape-retrieval analysis of X-ray scattering spectra, we further determine the average shape of nanocrystals. These results allow us to generate three-dimensional, atomistic reconstructions of graded core/shell nanocrystals. We use these reconstructions to calculate solid-state Zn diffusion in the Ag-In-Se nanocrystals and the lattice mismatch between nanocrystal monolayers. Finally, we apply these findings to propose design rules for optimal shell structure and record-luminescent core/shell nanocrystals.

AB - Engineering the compositional gradient for core/shell semiconductor nanocrystals improves their optical properties. To date, however, the structure of graded core/shell nanocrystal emitters has only been qualitatively described. In this paper, we demonstrate an approach to quantify nanocrystal structure, selecting graded Ag-In-Se/ZnSe core/shell nanocrystals as a proof-of-concept material. A combination of multi-energy small-angle X-ray scattering and electron microscopy techniques enables us to establish the radial distribution of ZnSe with sub-nanometer resolution. Using ab initio shape-retrieval analysis of X-ray scattering spectra, we further determine the average shape of nanocrystals. These results allow us to generate three-dimensional, atomistic reconstructions of graded core/shell nanocrystals. We use these reconstructions to calculate solid-state Zn diffusion in the Ag-In-Se nanocrystals and the lattice mismatch between nanocrystal monolayers. Finally, we apply these findings to propose design rules for optimal shell structure and record-luminescent core/shell nanocrystals.

UR - http://www.scopus.com/inward/record.url?scp=85029506586&partnerID=8YFLogxK

U2 - 10.1038/s41598-017-11996-2

DO - 10.1038/s41598-017-11996-2

M3 - Article

AN - SCOPUS:85029506586

VL - 7.2017

JO - Scientific reports (London : Nature Publishing Group)

JF - Scientific reports (London : Nature Publishing Group)

SN - 2045-2322

IS - 1

M1 - 11718

ER -