Stanford Advisors

All Publications

  • Effect of Adventitious Carbon on Pit Formation of Monolayer MoS2. Advanced materials (Deerfield Beach, Fla.) Park, S., Siahrostami, S., Park, J., Mostaghimi, A. H., Kim, T. R., Vallez, L., Gill, T. M., Park, W., Goodson, K. E., Sinclair, R., Zheng, X. 2020: e2003020


    Forming pits on molybdenum disulfide (MoS2 ) monolayers is desirable for (opto)electrical, catalytic, and biological applications. Thermal oxidation is a potentially scalable method to generate pits on monolayer MoS2 , and pits are assumed to preferentially form around undercoordinated sites, such as sulfur vacancies. However, studies on thermal oxidation of MoS2 monolayers have not considered the effect of adventitious carbon (C) that is ubiquitous and interacts with oxygen at elevated temperatures. Herein, the effect of adventitious C on the pit formation on MoS2 monolayers during thermal oxidation is studied. The in situ environmental transmission electron microscopy measurements herein show that pit formation is preferentially initiated at the interface between adventitious C nanoparticles and MoS2 , rather than only sulfur vacancies. Density functional theory (DFT) calculations reveal that the C/MoS2 interface favors the sequential adsorption of oxygen atoms with facile kinetics. These results illustrate the important role of adventitious C on pit formation on monolayer MoS2 .

    View details for DOI 10.1002/adma.202003020

    View details for PubMedID 32743836

  • Profitable Production of Stable Electrical Power Using Wind-battery Hybrid Power Systems: A Case Study from Mt. Taegi, South Korea INTERNATIONAL JOURNAL OF PRECISION ENGINEERING AND MANUFACTURING-GREEN TECHNOLOGY Park, S., Hang, G., Koo, J., Choi, H., Shim, J. 2019; 6 (5): 919–30
  • Rapid Flame-Annealed CuFe2O4 as Efficient Photocathode for Photoelectrochemical Hydrogen Production ACS SUSTAINABLE CHEMISTRY & ENGINEERING Park, S., Baek, J., Zhang, L., Lee, J., Stone, K. H., Cho, I., Guo, J., Jung, H., Zheng, X. 2019; 7 (6): 5867–74
  • Selective and Efficient Gd-Doped BiVO4 Photoanode for Two-Electron Water Oxidation to H2O2 ACS ENERGY LETTERS Baek, J., Gill, T., Abroshan, H., Park, S., Shi, X., Norskoy, J., Jung, H., Siahrostami, S., Zheng, X. 2019; 4 (3): 720–28
  • Enhancing Catalytic Activity of MoS2 Basal Plane S-Vacancy by Co Cluster Addition ACS ENERGY LETTERS Park, S., Park, J., Abroshan, H., Zhang, L., Kim, J., Zhang, J., Guo, J., Siahrostami, S., Zheng, X. 2018; 3 (11): 2685–93
  • Wafer-recyclable, environment-friendly transfer printing for large-scale thin-film nanoelectronics PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Wie, D., Zhang, Y., Kim, M., Kim, B., Park, S., Kim, Y., Irazoqui, P. P., Zheng, X., Xu, B., Lee, C. 2018; 115 (31): E7236–E7244


    Transfer printing of thin-film nanoelectronics from their fabrication wafer commonly requires chemical etching on the sacrifice of wafer but is also limited by defects with a low yield. Here, we introduce a wafer-recyclable, environment-friendly transfer printing process that enables the wafer-scale separation of high-performance thin-film nanoelectronics from their fabrication wafer in a defect-free manner that enables multiple reuses of the wafer. The interfacial delamination is enabled through a controllable cracking phenomenon in a water environment at room temperature. The physically liberated thin-film nanoelectronics can be then pasted onto arbitrary places of interest, thereby endowing the particular surface with desirable add-on electronic features. Systematic experimental, theoretical, and computational studies reveal the underlying mechanics mechanism and guide manufacturability for the transfer printing process in terms of scalability, controllability, and reproducibility.

    View details for PubMedID 30012591

  • Ultrafast Flame Annealing of TiO2 Paste for Fabricating Dye-Sensitized and Perovskite Solar Cells with Enhanced Efficiency SMALL Kim, J., Chai, S., Cho, Y., Cai, L., Kim, S., Park, S., Park, J., Zheng, X. 2017; 13 (42)
  • Electrochemical generation of sulfur vacancies in the basal plane of MoS2 for hydrogen evolution NATURE COMMUNICATIONS Tsai, C., Li, H., Park, S., Park, J., Han, H. S., Norskov, J. K., Zheng, X., Abild-Pedersen, F. 2017; 8


    Recently, sulfur (S)-vacancies created on the basal plane of 2H-molybdenum disulfide (MoS2) using argon plasma exposure exhibited higher intrinsic activity for the electrochemical hydrogen evolution reaction than the edge sites and metallic 1T-phase of MoS2 catalysts. However, a more industrially viable alternative to the argon plasma desulfurization process is needed. In this work, we introduce a scalable route towards generating S-vacancies on the MoS2 basal plane using electrochemical desulfurization. Even though sulfur atoms on the basal plane are known to be stable and inert, we find that they can be electrochemically reduced under accessible applied potentials. This can be done on various 2H-MoS2 nanostructures. By changing the applied desulfurization potential, the extent of desulfurization and the resulting activity can be varied. The resulting active sites are stable under extended desulfurization durations and show consistent HER activity.

    View details for DOI 10.1038/ncomms15113

    View details for Web of Science ID 000399985300001

  • Molybdenum disulfide catalyzed tungsten oxide for on-chip acetone sensing APPLIED PHYSICS LETTERS Li, H., Ahn, S. H., Park, S., Cai, L., Zhao, J., He, J., Zhou, M., Park, J., Zheng, X. 2016; 109 (13)

    View details for DOI 10.1063/1.4962946

    View details for Web of Science ID 000384747900042