Correlated Roles of Temperature and Dimensionality for Multiple Exciton Generation and Electronic Structures in Quantum Dot Superlattices

Abstract

Quantum dot superlattices (QDSLs), which are one-, two-, and three-dimensional periodic superlattices composed of QDs, induce dimensionality dependent quantum resonance among component QDs and thus represent a new type of condensed matter exhibiting novel energy, exciton, and carrier dynamics. We focused on the two important parameters, dimensionality and temperature, and identified their correlated roles to determine the electronic and photoexcited properties intrinsic to each QDSL at each dimensionality and temperature. We computationally demonstrated that the multiple exciton generation is significantly accelerated at higher temperature especially in the higher-dimensional QDSLs, indicating their great advantage especially at ambient temperature compared to an isolated zero-dimensional QD. Both dimensionality and temperature can be crucial and correlated parameters for independent tailoring of the properties of the QDSLs without changing the size, shape, and compositions of component QDs. The physical insights and advantage of the QDSLs we found here will lead to designing efficient and space-saving optoelectronic and photovoltaic devices that work at ambient temperature.