First-principles investigations of the geometric structures and electronic properties of pristine and Ag/Au-doped Janus MoSSe/C60 and WSSe/C60 heterostructures

Based on first-principles investigations, the interactions of C60 molecules with pristine and Ag/Au-doped Janus MoSSe and WSSe are explored. The results reveal that the adsorption energies of Ag or Au adsorbed on the S-side and Se-side of Janus MoSSe are very close. The adsorption energies of Ag/Au-doped Janus MoSSe/C60 heterostructures are more negative than those of Ag/Au-doped MoS2 (or MoSe2)/C60. Moreover, in the Ag/Au-doped Janus MoSSe/C60 system, the adsorption energy on the S side is more negative than that on the Se side, indicating that the former one has a stronger interaction. Unlike Janus MoSSe, C60 and Janus MoSSe/C60, Ag-doped Janus MoSSe/C60 heterojunction has a negative Poisson ratio. With the analysis of the strain effect on the adsorption energy of MoSSe-Ag-C60-S-side system, it is found that strain is more beneficial to the adsorption process. With different adsorption sides of Ag-doped Janus MoSSe/C60, Janus MoSSe exhibits opposite behaviors during charge transfer progress. Similar behaviors also occur in Au-doped Janus WSSe/C60 system. Band structures demonstrate that the pristine Janus MoSSe (or WSSe)/C60 heterostructures possess semiconductor properties, while Ag/Au-doped Janus MoSSe (or WSSe)/C60 heterostructures exhibit metallic behaviors. These perspectives can provide mechanical, electronic and engineering applications of nanodevices in the future.