Local Enhancement of Exciton Emission of Monolayer MoS2 by Copper Phthalocyanine Nanoparticles

Monolayer transition-metal dichalcogenides (1L-TMDs) provide ideal platforms to study light emission using two-dimensionally confined excitons. Recent studies have shown that the exciton emissions of 1L-TMDs can be conveniently modulated by developing heterostructures with zero-dimensional nanoparticles (NPs) or quantum dots. In this study, we synthesized organic semiconducting copper phthalocyanine (CuPc) NPs with sizes in the range of 30-70 nm by a re-precipitation method and decorated the chemical vapor deposition-grown 1L-MoS2 with these NPs. This hybrid system exhibited a 6 times larger local photoluminescence (PL) at the positions of the CuPc NPs compared with the pristine 1L-MoS2 sample. The PL enhancement and spectral modification of the 1L-MoS2 decorated with CuPc NPs were attributed to the p-doping effect of the CuPc NPs, confirmed by spectral analysis and field-effect transistor measurements.