2018~

• 2018

  2D Single?Crystalline Copper Nanoplates as a Conductive Filler for Electronic Ink Applications

  Lee, J. W., Han, J., Lee, D. S., Bae, S., Lee, S. H., Lee, S. K., Moon, B. J., Choi, C. J., Wang, G., & Kim, T. W. (2018), Small, 14(8), 1703312.

  Large-scale 2D single-crystalline copper nanoplates (Cu NPLs) are synthesized by a simple hydrothermal method. The combination of a mild reductant, stabilizer, and shape modifier allows the dimensional control of the Cu nanocrystals from 1D nanowires (NWs) to 2D nanoplates. High-resolution transmission electron microscopy (HR-TEM) reveals that the prepared Cu NPLs have a single-crystalline structure. From the X-ray photoelectron spectroscopy (XPS) analysis, it is found that iodine plays an important role in the modification of the copper nanocrystals through the formation of an adlayer on the basal plane of the nanoplates. Cu NPLs with an average edge length of 10 μm are successfully synthesized, and these Cu NPLs are the largest copper 2D crystals synthesized by a solution-based process so far. The application of the metallic 2D crystals as a semitransparent electrode proves their feasibility as a conductive filler, exhibiting very low sheet resistance compared to Cu NWs and a transmittance near 75%. The efficient charge transport is due to the increased contact area between each Cu NPL, i.e., so-called plane contact (2D electrical contact). In addition, this type of contact enhances the currentcarrying capability of the Cu NPL electrodes, implying that the large-size Cu NPLs are promising conductive fillers for printable electrode applications.

  

• 2020 ~ 2024

  Electromagnetic Functionalization of Wide?Bandgap Dielectric Oxides by Boron Interstitial Doping.

  Park, D. S., Rees, G. J., Wang, H., Rata, D., Morris, A. J., Maznichenko, I. V., Ostanin, S., Bhatnagar, A., Choi, C. J., ... & McConville, C. F. (2018), Advanced Materials, 30(39), 1802025.

  A surge in interest of oxide-based materials is testimony for their potential utility in a wide array of device applications and offers a fascinating landscape for tuning the functional properties through a variety of physical and chemical parameters. In particular, selective electronic/defect doping has been demonstrated to be vital in tailoring novel functionalities, not existing in the bulk host oxides. Here, an extraordinary interstitial doping effect is demonstrated centered around a light element, boron (B). The host matrix is a novel composite system, made from discrete bulk LaAlO3:LaBO3 compounds. The findings show a spontaneous ordering of the interstitial B cations within the host LaAlO3 lattices, and subsequent spin-polarized charge injection into the neighboring cations. This leads to a series of remarkable cation-dominated electrical switching and high-temperature ferromagnetism. Hence, the induced interstitial doping serves to transform a nonmagnetic insulating bulk oxide into a ferromagnetic ionic?electronic conductor. This unique interstitial B doping effect upon its control is proposed to be as a general route for extracting/modifying multifunctional properties in bulk oxides utilized in energy and spin-based applications.