CdSe/bis(Dithiocarbamate) Linker Multilayered Hybrid Films: a Photo-Physical and Quantum Chemical Overview

Photo-voltaic processes are the key ingredient for the conversion of solar energy in green electric power. Hybrid systems obtained by the integration of semiconductor nano-particles and organic conjugated molecules are promising materials for solar cell applications . These materials combine the properties of both organic and inorganic semiconductors, but they have the advantage of being more flexible than the usually employed inorganic semiconductors and more resistant against oxidative degradation than the organic ones. In the present work we explore hybrid materials where a commercial ethylene-1,2-bis(dithiocarbamate) (EDTC) (Chart 1) was reacted with (hexadecylamine/stearate)-capped CdSe nanocrystals (NCs) to form multilayers on ITO glass via layer-by-layer alternation. The materials were investigated by UV-vis and FTIR spectroscopy, photoluminescence and photoconductivity. The photoconductivity of the multilayered films obtained with such linker is strongly enhanced, compared with analogous films produced with adipate (CAC4CA) anions of comparable length and structure, attaining values 10 times higher. Despite the demonstration of superior photoconduction performances of the films, the role played by the bis(dithiocarbamate) remain elusive . Pump-Probe investigations supported by Density Fuctional Theory (DFT) calculations helped us to describe the role played by the bis(dithiocarbamate) group on the photoconductive behavior of the films.