Reduced Dielectric Screening and Enhanced Energy Transfer in Single- and Few-Layer MoS[subscript 2]

We report highly efficient nonradiative energy transfer from cadmium selenide (CdSe) quantum dots to monolayer and few-layer molybdenum disulfide (MoS[subscript 2]). The quenching of the donor quantum dot photoluminescence increases as the MoS[subscript 2] flake thickness decreases with the highest efficiency (>95%) observed for monolayer MoS[subscript 2]. This counterintuitive result arises from reduced dielectric screening in thin layer semiconductors having unusually large permittivity and a strong in-plane transition dipole moment, as found in MoS[subscript 2]. Excitonic energy transfer between a zero-dimensional emitter and a two-dimensional absorber is fundamentally interesting and enables a wide range of applications including broadband optical down-conversion, optical detection, photovoltaic sensitization, and color shifting in light-emitting devices.United States. Dept. of Energy. Office of Basic Energy Sciences (Award DE-SC0001088