TY - JOUR
T1 - First principle study of capping energies and electronic states in stoichiometric and nonstoichiometric PbSe nanoclusters
AU - Grassi, Fabio
AU - Argeri, Mario
AU - Marchese, Leonardo
AU - Cossi, Maurizio
PY - 2013/12/12
Y1 - 2013/12/12
N2 - A large variety of PbSe nanoclusters have been modeled at the DFT level, to study their structure, their affinity for different ligands and their electronic properties, also depending on surface passivation. The clusters are extracted from the bulk rock salt structure with cubic, prism, truncated cubic, cuboctahedral and octahedral shape and they are fully relaxed, before computing the addition energies of methylamine and formate anions in different positions, to model the process of surface passivation. Then the density of states of all the clusters is computed, to study in particular the band gap and the behavior of the so-called intragap states, which affect the photophysical properties of the nanoparticles, also acting as trap states for charge carriers. We confirm the strong relationship between nanocluster off-stoichiometry and intragap states: such states can be localized on the surface, in the bulk or delocalized over the nanoparticle, according to the source of off-stoichiometry. The ability of different ligands to eliminate the intragap states are tested and discussed, also proposing nonstandard capping molecules.
AB - A large variety of PbSe nanoclusters have been modeled at the DFT level, to study their structure, their affinity for different ligands and their electronic properties, also depending on surface passivation. The clusters are extracted from the bulk rock salt structure with cubic, prism, truncated cubic, cuboctahedral and octahedral shape and they are fully relaxed, before computing the addition energies of methylamine and formate anions in different positions, to model the process of surface passivation. Then the density of states of all the clusters is computed, to study in particular the band gap and the behavior of the so-called intragap states, which affect the photophysical properties of the nanoparticles, also acting as trap states for charge carriers. We confirm the strong relationship between nanocluster off-stoichiometry and intragap states: such states can be localized on the surface, in the bulk or delocalized over the nanoparticle, according to the source of off-stoichiometry. The ability of different ligands to eliminate the intragap states are tested and discussed, also proposing nonstandard capping molecules.
UR - http://www.scopus.com/inward/record.url?scp=84890541521&partnerID=8YFLogxK
U2 - 10.1021/jp4102465
DO - 10.1021/jp4102465
M3 - Article
SN - 1932-7447
VL - 117
SP - 26396
EP - 26404
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 49
ER -