Strong interlayer photoresponses in monolayer (ML) semiconductor stacks, such as substantial light absorption and charge separation across interlayer band alignments, suggest potentials for two-dimensional photovoltaics (PVs). Here, we report an interlayer PV conversion in a type-I ML heterojunction by ultrafast interlayer transfer of photoexcited hot carriers in the broad spectral ranges. Specifically, low-energy photoexcitation on a stack of a narrow-band-gap (Eg) Bi2Te3 few-layer and a large-Eg MoS2 ML permits interlayer transfer of transient hot carriers from the Bi2Te3 layer to the excitonic states of the neighboring MoS2 ML within a time scale of ∼70 fs, producing interlayer charge separation. Thereby we achieve substantial conversion efficiency from a MoS2 ML with visible to infrared light illumination.
Bibliographical noteFunding Information:
This work was supported by the Institute for Basic Science (IBS), Korea, under the Project Code number IBS-R014-A1-2017-a00. S.C., S.S. and H.C. were supported by the National Research Foundation of Korea (NRF) through the government of Korea (MSIP) (Grant No. NRF-2015R1A2A1A10052520 NRF-2016R1A4A1012929).
© 2017 American Chemical Society.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Atomic and Molecular Physics, and Optics
- Electrical and Electronic Engineering