title: Core-shell interaction and its impact on the optical absorption of pure and doped core-shell CdSe/ZnSe nanoclusters.
abstract: The structural, electronic, and optical properties of core-shell nanoclusters, (CdSe)(x)@(CdSe)(y) and their Zn-substituted complexes of x = 2-4 and y = 16-28, were studied with density functional theory calculations. The substitution was applied in the cores, the shells, and/or the whole clusters. All these clusters are characterized by their core-shell structures in which the core-shell interaction was found different from those in core or in shell, as reflected by their bondlengths, volumes, and binding energies. Moreover, the core and shell combine together to compose a new cluster with electronic and optical properties different from those of separated individuals, as reflected by their HOMO-LUMO gaps and optical absorptions. With the substitution of Cd by Zn, the structural, electronic, and optical properties of clusters change regularly. The binding energy increases with Zn content, attributed to the strong Zn-Se bonding. For the same core/shell, the structure with a CdSe shell/core has a narrower gap than that with a ZnSe shell/core. The optical absorption spectra also change accordingly with Zn substitution. The peaks blueshift with increasing Zn concentration, accompanying with shape variations in case large number of Cd atoms are substituted. Our calculations reveal the core-shell interaction and its influence on the electronic and optical properties of the core-shell clusters, suggesting a composition-structure-property relationship for the design of core-shell CdSe and ZnSe nanoclusters.
authors.affiliation: Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China.
authors.forename: Xinqin
authors.initials: X
authors.lastname: Wang
authors.affiliation: Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China.
authors.forename: Yingqi
authors.initials: Y
authors.lastname: Cui
authors.affiliation: College of Chemistry and Environment Protection Engineering, Southwest University for Nationalities, Chengdu 610041, People's Republic of China.
authors.forename: Shengping
authors.initials: S
authors.lastname: Yu
authors.affiliation: Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: Institute of Atomic and Molecular Physics, Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610065, People's Republic of China.
authors.forename: Mingli
authors.initials: M
authors.lastname: Yang