Basal-Plane Ligand Functionalization on Semiconducting 2H-MoS2Monolayers.
Molybdenum disulfide (MoS2) is a two-dimensional material promising for electronic, optical, and catalytic applications. To fully harness its potential, functionalization is essential to controlling its properties. However, MoS2functionalization has been mostly limited to either 1T-phase MoS2or the edges of 2H-phase MoS2, and the chemistry of covalent functionalization on the basal plane of 2H-MoS2is poorly understood. Here, we report a facile approach to covalently functionalize chemical vapor deposition (CVD) grown 2H-MoS2monolayers (MLs), as well as mechanically exfoliated MoS2, via thiol conjugation at sulfur vacancies on the basal plane. Thorough characterization confirmed the functionalization by thiol molecules on MoS2MLs, and we experimentally proved that sulfur vacancies in MoS2MLs play a key role in the functionalization of basal planes. By the controlling of the amount of sulfur vacancies via sulfur annealing, the degree of MoS2functionalization was effectively tuned. Because thiol conjugation partially repairs or passivates sulfur vacancies, enhanced photoluminescence response and decreased active sites for hydrogen evolution catalysis were observed for functionalized MoS2. Moreover, such functionalization can be utilized for making MoS2-based heterostructures, an example of which was demonstrated using a dithiol molecule to link MoS2layers and PbSe quantum dots. These results provide new understanding and insights on the surface chemistry of MoS2and open up more opportunities for MoS2MLs with well-controlled properties and broader applications.
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Qi
Q
Ding
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Kyle J
KJ
Czech
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Yuzhou
Y
Zhao
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Jianyuan
J
Zhai
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Robert J
http://orcid.org/0000-0003-3821-9625
RJ
Hamers
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
John C
JC
Wright
Department of Chemistry, University of Wisconsin-Madison , 1101 University Avenue, Madison, Wisconsin 53706, United States.
Song
http://orcid.org/0000-0001-8693-7010
S
Jin
MoS2; basal plane; ligand functionalization; monolayer; sulfur vacancy