Controllable Interlayer Charge and Energy Transfer in Perovskite Quantum Dots/ Transition Metal Dichalcogenide Heterostructures

Efficient interlayer charge and energy transfer are explored in CsPbBr2I quantum dots/MoS2 heterostructure. When perovskite QDs directly contact MoS2, charge transfer from QDs to MoS2 dominates the nonradiative exciton relaxation in QDs/MoS2 heterostructure. With the layer number of MoS2 reducing to a monolayer, nonradiative exciton relaxation rate increases due to reduced dielectric effect and changed energy band structure of MoS2. Then an hexagonal boron nitride (h-BN) spacer is inserted between QDs and a monolayer MoS2, in which nonradiative exciton relaxation rate is dominated by excitonic energy transfer from QDs to MoS2. With the spacer thickness increasing, nonradiative exciton relaxation rate decays as 1/d(3.03) that is slower than the result 1/d(4) of Forster theory. This is attributed to strong near-field dipole-dipole coupling interaction in QDs/h-BN/MoS2 heterostructure. Controllable interlayer charge and energy transfer potentially enable new avenues for designing optoelectronic devices, as well as for studying fundamental issue of tunable light-matter interaction at nanoscale vision.