Remarkable Energy Transfer Efficiency in Spatially Separated 2D Heterostructure via Establishing Entangled States by Bloch‐Surface Plasmon Polariton

Abstract Establishing quantum mechanically entangled states between spatially separated 2D heterostructure offers a way to tailor novel energy transfer mechanisms at the precision of atomic level. Here, strongly coupled systems formed by monolayer WS 2 , spatially separated monolayer MoS 2 , and Ag nanoholes (Ag‐NHs) with square lattice are investigated by using an ultrafast pump‐probe approach. From transient absorption spectra of the prototypical Ag‐NHs/WS 2 /SiO 2 (10 nm)/MoS 2 heterostructures, a Rabi splitting up to 80 meV is observed, which is almost 2 1/2 times larger than that of each individual component. The result is as expected since Rabi splitting depends on the square root of the layer number involved, thus suggesting that the A exciton of WS 2 and spatially separated B exciton of MoS 2 are entangled by the Bloch‐surface plasmon polariton mode. Additionally, whether the donor or the acceptor is excited, the bleaching signals in the heterostructures all appear instantaneously and exhibit exactly the same dynamic process, further clearly highlighting the presence of quantum mechanically entangled states. From another perspective, such entangled states assist remarkably efficient energy transfer, which is also demonstrated by significantly enhanced fluorescence emission from MoS 2 , with an enhancement factor of 25. This research establishes the scientific foundation for developing related heterostructure optoelectronic devices.