Energy transfer in van der Waal stacked MoS₂ – Graphene Quantum Dots with Ab-initio validation

Graphene based van der Waals (vdW) heterostructures can facilitate enticing charge transfer dynamics in between the layers with emission of excitonic quasi-particles. In this work, an attempt has been made to probe such van der Waal (vdW) heterostructures between few layer MoS₂ sheet embedded quantum dot (QD) and amine-functionalized graphene quantum dot (GQD) to explore the energy transfer mechanism. Our findings reveal interesting non-radiative Forster type energy transfer with quenching of functional GQD PL after GQD/MoS₂ hetero interface formation and validates the existing charge transfer shown that is analogous between a 0D and 2D system. This non-radiative type energy transfer characteristics from GQD into MoS₂ layer through vdW interaction has been confirmed by with a combination of photoluminescence and time decay analyses with ab-initio calculation affirms the same observation with shifting of Fermi level in density of states towards conduction band in van der Waals distance separation limit. This result encourage exploration of optical properties in other QD/2D based heterostructures for understanding the charge transfer mechanism and luminescence quenching for future optoelectronic device and optical sensing applications.

[1] Roy et al. Nanoscale 2018, 10, 16822.