How isolated are the electronic states of the core in core/shell nanoparticles?

TY - JOUR

T1 - How isolated are the electronic states of the core in core/shell nanoparticles?

AU - Xie, Zuoti

AU - Markus, Tal Z.

AU - Gotesman, Gilad

AU - Deutsch, Zvicka

AU - Oron, Dan

AU - Naaman, Ron

PY - 2011/2/22

Y1 - 2011/2/22

N2 - We investigated how isolated are the electronic states of the core in a core-shell (c/s) nanoparticles (NPs) from the surface, when the particles are self-assembled on Au substrates via a dithiol (DT) organic linker. Applying photoemission spectroscopy the electronic states of CdSe core only and CdSe/ZnS c/s NPs were compared. The results indicate that in the c/s NPs the HOMO interacts strongly with electronic states in the Au substrate and is pinned at the same energies, relative to the Fermi level, as the core only NPs. When the capping molecules of the NPs were replaced with thiolated molecules, an interaction between the thiol groups and the electronic states of the NPs was observed that depends on the properties of the NPs studied. Thiols binding to the NPs induce the formation of surface trap states. However, while for the core only CdSe NPs the LUMO states are strongly coupled to the surface traps, independent of their size, this coupling is size dependent in the case of the CdSe/ZnS c/s NPs. For a large core, the LUMO is decoupled from the surface trap states. When the core is small enough, the LUMO is delocalized and interacts with these states.

AB - We investigated how isolated are the electronic states of the core in a core-shell (c/s) nanoparticles (NPs) from the surface, when the particles are self-assembled on Au substrates via a dithiol (DT) organic linker. Applying photoemission spectroscopy the electronic states of CdSe core only and CdSe/ZnS c/s NPs were compared. The results indicate that in the c/s NPs the HOMO interacts strongly with electronic states in the Au substrate and is pinned at the same energies, relative to the Fermi level, as the core only NPs. When the capping molecules of the NPs were replaced with thiolated molecules, an interaction between the thiol groups and the electronic states of the NPs was observed that depends on the properties of the NPs studied. Thiols binding to the NPs induce the formation of surface trap states. However, while for the core only CdSe NPs the LUMO states are strongly coupled to the surface traps, independent of their size, this coupling is size dependent in the case of the CdSe/ZnS c/s NPs. For a large core, the LUMO is decoupled from the surface trap states. When the core is small enough, the LUMO is delocalized and interacts with these states.

KW - core/shell nanoparticles

KW - electronic structures

KW - electronic wave function

KW - photoelectron spectroscopy

KW - surface trap states

UR - http://www.scopus.com/inward/record.url?scp=79951909961&partnerID=8YFLogxK

U2 - 10.1021/nn102002x

DO - 10.1021/nn102002x

M3 - 文章

C2 - 21207972

AN - SCOPUS:79951909961

SN - 1936-0851

VL - 5

SP - 863

EP - 869

JO - ACS Nano

JF - ACS Nano

IS - 2

ER -