Modeling UV–Vis spectra of low dimensional materials usingelectrostatic embedding: The case of CdSe

Davide Luise, Liam Wilbraham, Frédéric Labat, Ilaria Ciofini

DOI: 10.1002/jcc.26534

ABSTRACT:We present a generalization of a self-consistent electrostatic embedding approach

(SC-Ewald) devised to investigate the photophysical properties of 3D periodic mate-

rials, to systems in one- or two-dimensional (2D) reduced periodicity. In this

approach, calculations are carried out on a small finite molecular cluster extracted

from a periodic model, while the crystalline environment is accounted for by an array

of point charges which are fitted to reproduce the exact electrostatic potential

(at ground or the excited state) of the infinite periodic system. Periodic density func-

tional theory (DFT) calculations are combined with time dependent DFT calculations

to simulate absorption and emission properties of the extended system under investi-

gation. We apply this method to compute the UV–Vis. spectra of bulk and quantum-

confined 0D quantum dots and 2D extended nanoplatelets of CdSe, due to their

relevance as sensitizers in solar cells technologies. The influence of the size and

shape of the finite cluster model chosen in the excited state calculations was also

investigated and revealed that, although the long-range electrostatics of the environ-

ment are important for the calculation of the UV–Vis, a subtle balance between

short- and long-range effects exists. These encouraging results demonstrate that this

self-consistent electrostatic embedding approach, when applied in different dimen-

sions, can successfully model the photophysical properties of diverse material classes,

making it an attractive low-cost alternative to far more computationally demanding

electronic structure methods for excited state calculations