Publication

Advanced Multifunctional Nanocomposite Lab

Selected Representative Publications

  • 2023
  • Giant thermal rectification efficiency by geometrically enhanced asymmetric non-linear radiation
  • Seongkyun Kim , Taeyeop Kim , Jaehyun Sung , Yongjun Kim , Dongwoo Lee and Seunghyun Baik Materials Horizons
  • Thermal rectification is an asymmetric heat transport phenomenon where thermal conductance changes depending on the temperature gradient direction. The experimentally reported efficiency of thermal rectification materials and devices, which are applicable for a wide range of temperatures, is relatively low. Here we report a giant thermal rectification efficiency of 218% by maximizing asymmetry in …
  • 2022
  • Invariable resistance of conductive nanocomposite over 30% strain
  • C. MUHAMMED AJMAL, SEOKJAE CHA, WONJOON KIM, K. P. FASEELA, HEEJUN YANG, AND SEUNGHYUN BAIK Science Advances
  • The dependence of the electrical resistance on materials’ geometry determines the performance of conductive nanocomposites. Here, we report the invariable resistance of a conductive nanocomposite over 30% strain. This is enabled by the in situ–generated hierarchically structured silver nanosatellite particles, realizing a short interparticle distance (4.37 nm) in a stretchable silicone rubber matr…
Enhanced crystallinity of CH3NH3PbI3 by the pre-coordination of PbI2–DMSO powders for highly reproducible and efficient planar heterojunction perovskite solar cells
Author
Jiyong Lee and Seunghyun Baik
Journal
RSC Advances
Vol
8
Page
1005-1013
Year
2018
Solution processable CH3NH3PbI3 has received considerable attention for highly-efficient perovskite solar cells. However, the different solubility of PbI2 and CH3NH3I is problematic, initiating active solvent engineering research using dimethyl sulfoxide (DMSO). Here we investigated the pre-coordination of PbI2–DMSO powders for planar heterojunction perovskite solar cells fabricated by a low-temperature process (≤100 °C). Pre-coordination was carried out by simple mechanical mixing using a mortar and pestle. The composition of PbI2–DMSOx (x = 0, 1, or 2) in the powder mixture was investigated by gradually increasing mechanical mixing time, and a dominant composition of PbI2–DMSO1 was obtained after a 10 min mixing process. The pre-coordinated PbI2–DMSO powders were then blended with CH3NH3I in DMF to make the CH3NH3PbI3 film by toluene-assisted spin-coating and heat treatment. Compared with the one-step blending of CH3NH3I, PbI2, and DMSO in DMF, the pre-coordination method resulted in better dissolution of PbI2, larger grain size, and pinhole-free morphology. Consequently, absorption, fluorescence, carrier lifetime, and charge extraction were enhanced. The average open-circuit voltage (1.046 V), short-circuit current (22.9 mA cm−2), fill factor (73.5%), and power conversion efficiency (17.6%) were increased by 2–12% with decreased standard deviations (13–50%), compared with the one-step blending method. The best efficiency was 18.2%. The simple mechanical pre-coordination of PbI2–DMSO powders was very effective in enhancing the crystallinity of CH3NH3PbI3 and photovoltaic performance.