Trilayer-cubic core-shell structure of PbS/EuS nanocrystals revealed by the combination of the synchrotron small-angle X-ray scattering method and energy-dispersive X-ray spectroscopy

• Published in: Dalton transactions : an international journal of inorganic chemistry 2013-12, Vol.42 (45), p.16216-16221
• Main Authors: Masunaga, Hiroyasu, Ogawa, Hiroki, Nakashima, Takuya, Kawai, Tsuyoshi, Hikima, Takaaki, Takata, Masaki, Sasaki, Sono
• Format: Article
• Language: English
• Subjects: Atomic structure; Europium - chemistry; Lead - chemistry; Nanocrystals; Nanoparticles - chemistry; Nanoparticles - ultrastructure; SAXS; Scattering, Small Angle; Shells; Small angle X ray scattering; Spectrometry, X-Ray Emission; Spectroscopy; Sulfides - chemistry; Synchrotrons; X-Ray Diffraction; X-rays
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c3dt51710a

Multilayer nanostructure analysis has been carried out for core-shell PbS/EuS nanocrystals by the combination of the synchrotron small-angle X-ray scattering (SAXS) method and energy-dispersive X-ray spectroscopy (EDS). SAXS patterns of a dilute hexane solution of the PbS/EuS nanocrystals were measured at a high signal-to-noise ratio by using synchrotron radiation. Initial structure models used for SAXS data analyses were obtained from EDS images of the particle where Eu and O atoms are localized only in the shell part of a quasi-cubic particle and, on the other hand, Pb and S atoms in the core. By simulating the intensity of SAXS using multilayer-cubic models with various core-shell electron density distributions, it was found that the particle structure was explained approximately as a trilayer-cubic model having the PbS core and the EuS/Eu 2 O 3 shell. The diagonal length of the cubic particle was ca. 9.4 nm and the estimated thicknesses of EuS and Eu 2 O 3 layers in the shell were ca. 1.9 and 2.9 nm at maximum, respectively. Detailed information on a PbS/EuS/Eu 2 O 3 hetero-nanostructure was obtained by combining SAXS and EDS-TEM data analyses.