Optical features of ligated semiconducting quantum dots subjected to an electric field

Abstract

AbstractSemiconducting quantum dots (SQDs) are attractive materials for optoelectronic applications due to the size‐tunable band gaps, colloidal stability, and low‐cost solution processability. In this article, we investigate the modulations in the optical features of COOH + NH3 capped tetrahedral‐shape CdSe SQD in response to the external electric field. We base our calculations on an approach which combines the linear combination of atomic orbitals (LCAO) real‐time‐propagation‐time‐dependent density functional theory (rt‐TDDFT) technique (LCAO‐rt‐TDDFT) and transition contribution maps (two‐dimensional visualization of Kohn–Sham single electron–single hole transitions). Among other insights, our study indicates that electric field causes a redistribution of the oscillator strengths, early onset of absorption, and ligand‐derived trap states near the top of the valence band. These theoretical findings explain the origins of the electric field induced optical features of ligated SQDs.