Two-dimensional (2D) materials, like graphene and MoS2, exhibit unique layer-dependent bandgap transition which offers a great opportunity to design hybrid heterostructures through bandgap engineering. As combining with zero-dimensional (0D) quantum dots (QDs), the hybrids can possess greatly improved photoresponsivity via efficient interfacial charge transfer. Here, the kinetics of photoinduced interfaicial charge transfer between MoS2 and PbS/CdS QDs has been revealed by time-resolved photoluminescence (PL) microscopy, showing that the charge transfer rate increases with added number of MoS2 layers and as a result of increased driving force the between conduction band edge of MoS2 and PbS/CdS QDs. The manipulation of bandgap energy can also be achieved by using different size of QDs, given an enhancement of charge transfer rate by increasing the driving force in small QDs. We have evaluated the results with theoretical model of the Marcus theory, which is in good agreement with our observations. Understanding the interfacial charge transfer kinetics between QDs and 2D materials is crucial and useful for improving photon-to-current conversion efficiency in optoelectronics.

Layer-dependent charge transfer kinetics in atomically thin MoS2: PbS/CdS quantum dot hybrids

2019 Spring National Meeting

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