Highly Efficient Coherent Energy Transfer in Molecules near a MoS2 Nanodisk

We investigate the effect of coherence on the energy transfer between a donor and an acceptor molecule located on opposite sides of a ${\mathrm{Mo}\mathrm{S}}_2$ nanodisk. We study the energy-transfer efficiency by considering each molecule as a two-level quantum system using the Lindblad master equation, in the limits of fast (within nanoseconds) and slow (within microseconds) free-space relaxation. We incorporate the influence of the ${\mathrm{Mo}\mathrm{S}}_2$ nanodisk via the electromagnetic Green’s-function approach and take into account the donor dissipation and the acceptor charge-separation rate. We compare the energy-transfer efficiency with and without quantum coherence, for various separation distances and dipole orientations of the donor and acceptor. We find that the presence of the ${\mathrm{Mo}\mathrm{S}}_2$ nanodisk enhances the donor and acceptor relaxation rate, as well as the coherent and the incoherent coupling between them. We also find high energy-transfer efficiency between the donor and acceptor in the presence of strong coherence, primarily at a small separation distance from the ${\mathrm{Mo}\mathrm{S}}_2$ nanodisk. Additionally, we observe ultrafast energy transfer in the presence of coherence, which is largely enhanced in comparison to the incoherent coupling, when the donor and acceptor transition energies are off resonant to the excitonic ${\mathrm{Mo}\mathrm{S}}_2$ resonances. These results are important for nanotechnology applications; in particular, the design of novel light-harvesting devices.