Excitation Energy Transfer in Nanohybrid System of Organic Molecule and Inorganic Transition Metal Dichalcogenides Nanoflake

TL;DR

This study theoretically investigates excitation energy transfer from a para-sexiphenyl molecule to a MoS₂ nanoflake, revealing that transfer efficiency depends on nanoflake size, molecular position, and distance, with energy transfer being the dominant process.

Contribution

It provides a detailed theoretical analysis of EET in an organic-inorganic nanohybrid, highlighting the dependence on nanoflake size and molecular positioning, which was not previously characterized.

Findings

Energy transfer is the dominant process in the system.

Transfer efficiency varies with nanoflake size and molecular position.

EET rates are calculated using Fermi's golden rule considering Coulomb coupling.

Abstract

Excitation energy transfer (EET) in an organic/inorganic nanohybrid system, composed of a single \textit{para}-sexiphenyl (6P) molecule physisorbed on a finite-sized MoS$_2$ nanoflake, is investigated theoretically. % The electronic structure of the MoS$_2$ nanoflake is described by using an 11-band tight-binding model, in which edge states are passivated with H atoms to restore a well-defined bandgap. % Within a configuration-interaction scheme, excitonic states are constructed and, for computational efficiency, approximated by uncorrelated electron-hole pairs in the relevant high-energy window. % The EET rates are evaluated via Fermi's golden rule, incorporating Coulomb coupling, thermal broadening, and spectral overlap between the molecular excitation and the MoS$_2$ nanoflake's electron-hole pairs. % Our results reveal that energy transfer from the molecule to the nanoflake is the dominant process, and its efficiency depends strongly on the size of the MoS$_2$ nanoflake, as well as the molecule's vertical distance and lateral position relative to the nanoflake.