Shell effect on the electron and hole reorganization energy of core-shell II-VI nanoclusters

- Core structures change significantly after encapsulation.
- Surface atoms are more ionic than inner atoms.
- Hole reorganization energy is less sensitive to cluster size and shell composition than electron reorganization energy.
- Itemized contributions of electron and hole reorganization energies are related to cluster size and shell composition.

Density functional theory calculations were performed to study the effect of shell encapsulation on the geometrical and electronic properties of pure and hybrid core-shell CdSe nanoclusters. The CdSe cores are distorted by the shells, and the shells exhibit distinct surface activity from the cores, which leads to remarkable changes in their electron transition behaviors. Although the electron and hole reorganization energies, which are related to the formation and recombination of electron-hole pairs, vary in a complicated way, their itemized contributions, potentials of electron extraction, ionization and affinity, and hole extraction (HEP), are dependent on the cluster size, shell composition and/or solvent. Our calculations suggest that the behaviors of charge carriers, free electrons and holes, in the semiconductor core-shell nanoclusters can be modulated by selecting appropriate cluster size and controlling the chemical composition of the shells.

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