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Engineering Chemically Exfoliated Large‐Area Two‐Dimensional MoS 2 Nanolayers with Porphyrins for Improved Light Harvesting
Author(s) -
Zhang Hanyu,
Choi Jungwook,
Ramani Arjun,
Voiry Damien,
Natoli Sean N.,
Chhowalla Manish,
McMillin David R.,
Choi Jong Hyun
Publication year - 2016
Publication title -
chemphyschem
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.016
H-Index - 140
eISSN - 1439-7641
pISSN - 1439-4235
DOI - 10.1002/cphc.201600511
Subject(s) - photocurrent , porphyrin , materials science , molybdenum disulfide , crystallite , photochemistry , tetraphenylporphyrin , zinc , nanotechnology , optoelectronics , chemistry , metallurgy
Molybdenum disulfide (MoS 2 ) is a promising candidate for electronic and optoelectronic applications. However, its application in light harvesting has been limited in part due to crystal defects, often related to small crystallite sizes, which diminish charge separation and transfer. Here we demonstrate a surface‐engineering strategy for 2D MoS 2 to improve its photoelectrochemical properties. Chemically exfoliated large‐area MoS 2 thin films were interfaced with eight molecules from three porphyrin families: zinc(II)‐, gallium(III)‐, iron(III)‐centered, and metal‐free protoporphyrin IX (ZnPP, GaPP, FePP, H 2 PP); metal‐free and zinc(II) tetra‐( N ‐methyl‐4‐pyridyl)porphyrin (H 2 T4, ZnT4); and metal‐free and zinc(II) tetraphenylporphyrin (H 2 TPP, ZnTPP). We found that the photocurrents from MoS 2 films under visible‐light illumination are strongly dependent on the interfacial molecules and that the photocurrent enhancement is closely correlated with the highest occupied molecular orbital (HOMO) levels of the porphyrins, which suppress the recombination of electron–hole pairs in the photoexcited MoS 2 films. A maximum tenfold increase was observed for MoS 2 functionalized with ZnPP compared with pristine MoS 2 films, whereas ZnT4‐functionalized MoS 2 demonstrated small increases in photocurrent. The application of bias voltage on MoS 2 films can further promote photocurrent enhancements and control current directions. Our results suggest a facile route to render 2D MoS 2 films useful for potential high‐performance light‐harvesting applications.