Education & Certifications

  • Postdoc, Stanford University, Materials Science & Engineering (2015)
  • Ph.D, Seoul National University, Chemical and Biological Engineering (2010)
  • B.S., Seoul National University, Chemical Engineering (2003)

All Publications

  • Vertical Heterostructure of Two-Dimensional MoS2 and WSe2 with Vertically Aligned Layers NANO LETTERS Yu, J. H., Lee, H. R., Hong, S. S., Kong, D., Lee, H., Wang, H., Xiong, F., Wang, S., Cui, Y. 2015; 15 (2): 1031-1035


    Two-dimensional (2D) layered materials consist of covalently bonded 2D atomic layers stacked by van der Waals interactions. Such anisotropic bonding nature gives rise to the orientation-dependent functionalities of the 2D layered materials. Different from most studies of 2D materials with their atomic layers parallel to substrate, we have recently developed layer vertically aligned 2D material nanofilms. Built on these developments, here, we demonstrate the synthesis of vertical heterostructure of n-type MoS2 and p-type WSe2 with vertically aligned atomic layers. Thin film of MoS2/WSe2 vertical structure was successfully synthesized without significant alloy formation. The heterostructure synthesis is scalable to a large area over 1 cm(2). We demonstrated the pn junction diode behavior of the heterostructure device. This novel device geometry opens up exciting opportunities for a variety of electronic and optoelectronic devices, complementary to the recent interesting vertical heterostructures with horizontal atomic layers.

    View details for DOI 10.1021/nl503897h

    View details for Web of Science ID 000349578000035

  • Two-dimensional layered transition metal disulphides for effective encapsulation of high-capacity lithium sulphide cathodes NATURE COMMUNICATIONS Seh, Z. W., Yu, J. H., Li, W., Hsu, P., Wang, H., Sun, Y., Yao, H., Zhang, Q., Cui, Y. 2014; 5

    View details for DOI 10.1038/ncomms6017

    View details for Web of Science ID 000342985900004

  • High-resolution three-photon biomedical imaging using doped ZnS nanocrystals NATURE MATERIALS Yu, J. H., Kwon, S., Petrasek, Z., Park, O. K., Jun, S. W., Shin, K., Choi, M., Il Park, Y., Park, K., Na, H. B., Lee, N., Lee, D. W., Kim, J. H., Schwille, P., Hyeon, T. 2013; 12 (4): 359-366

    View details for DOI 10.1038/NMAT3565

    View details for Web of Science ID 000317164900026

  • Giant Zeeman splitting in nucleation-controlled doped CdSe:Mn2+ quantum nanoribbons NATURE MATERIALS Yu, J. H., Liu, X., Kweon, K. E., Joo, J., Park, J., Ko, K., Lee, D., Shen, S., Tivakornsasithorn, K., Son, J. S., Park, J., Kim, Y., Hwang, G. S., Dobrowolska, M., Furdyna, J. K., Hyeon, T. 2010; 9 (1): 47-53


    Doping of semiconductor nanocrystals by transition-metal ions has attracted tremendous attention owing to their nanoscale spintronic applications. Such doping is, however, difficult to achieve in low-dimensional strongly quantum confined nanostructures by conventional growth procedures. Here we demonstrate that the incorporation of manganese ions up to 10% into CdSe quantum nanoribbons can be readily achieved by a nucleation-controlled doping process. The cation-exchange reaction of (CdSe)(13) clusters with Mn(2+) ions governs the Mn(2+) incorporation during the nucleation stage. This highly efficient Mn(2+) doping of the CdSe quantum nanoribbons results in giant exciton Zeeman splitting with an effective g-factor of approximately 600, the largest value seen so far in diluted magnetic semiconductor nanocrystals. Furthermore, the sign of the s-d exchange is inverted to negative owing to the exceptionally strong quantum confinement in our nanoribbons. The nucleation-controlled doping strategy demonstrated here thus opens the possibility of doping various strongly quantum confined nanocrystals for diverse applications.

    View details for DOI 10.1038/NMAT2572

    View details for Web of Science ID 000272854800018

    View details for PubMedID 19915554

  • Magnetic fluorescent delivery vehicle using uniform mesoporous silica spheres embedded with monodisperse magnetic and semiconductor nanocrystals JOURNAL OF THE AMERICAN CHEMICAL SOCIETY Kim, J., Lee, J. E., Lee, J., Yu, J. H., Kim, B. C., An, K., Hwang, Y., Shin, C. H., Park, J. G., Kim, J., Hyeon, T. 2006; 128 (3): 688-689


    We synthesized uniform pore-sized mesoporous silica spheres embedded with magnetite nanocrystal and quantum dots. The magnetic separation, luminescent detection, and controlled release of drugs were demonstrated using the uniform mesoporous silica spheres embedded with monodisperse nanocrystals.

    View details for Web of Science ID 000234815000010

    View details for PubMedID 16417336