Carrier dynamics of CdS/MoS2 heterostructure nanocrystal films affected by annealing effect

2D transition metal dichalcogenides (TMDCs) nanocrystals and related semiconductor–metal heterostructures are promising new materials for efficient opto-electrical conversion because of their unique physical and chemical properties. The design and optimization of such materials require the understanding of exciton and charge carrier dynamics. The illumination-dependent carrier dynamics of CdS/MoS 2 heterostructure nanocrystals (CdS/MoS 2 HNCs) film is investigated by employing the voltage-current test, in which the CdS nanocrystals (NCs) film is used as a reference. The photocurrent performance of carriers in the CdS/MoS 2 HNCs is 70 times higher than that in CdS NC film, owing to the excellent interfacial hole transfer from the CdS component to the monolayer MoS 2 in CdS/MoS 2 HNCs, which effectively reduces the bulk and surface charger recombination. It means that the remaining electron in CdS component after hole transfer plays an important role in the final photocurrent performance. The annealing effect also plays a positive role in the photocurrent performance of nanocrystal film for CdS/MoS 2 HNC and CdS NC film. In addition, the transient absorption test is also used to exclude the possibility of interfacial electron transfer. The final results suggest that the construction of nano-heterojunction can affect the carrier dynamics of nanomaterials and enhance light responsiveness, which is conductive to the design and application of photovoltaic devices in the future.