Publications by authors named "Yejung Lee"

Physical vapor deposition (PVD) is widely utilized for the production of organic semiconductor devices due to its ability to form thin layers with exceptional properties. Although the layers in the device usually consist of two or more components, there is limited understanding about the fundamental characteristics of such multicomponent vapor-deposited glasses. Here, spectroscopic ellipsometry was employed to characterize the densities, thermal stabilities, and optical properties of covapor deposited NPD and TPD glasses across the entire range of composition.

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Article Synopsis
  • The study investigates the stability of binary organic semiconductor glasses created through physical vapor deposition (PVD), specifically using a 50:50 mixture of TPD and m-MTDATA.
  • Results show that these binary glasses exhibit remarkable thermodynamic and kinetic stability when deposited at specific substrate temperatures (0.78-0.90 times the glass transition temperature).
  • The findings suggest that the mechanisms governing stability in single-component glasses also apply to codeposited mixtures, which could help in the development of improved organic electronic devices.
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Article Synopsis
  • The study focuses on the synthesis of single-phase spinel CoRhO nanotubes and their application for the oxygen evolution reaction (OER).
  • The authors highlight the significantly enhanced catalytic performance of these nanotubes compared to other materials used for OER.
  • The findings suggest that the unique structural properties of the CoRhO nanotubes contribute to their effectiveness as a catalyst in electrochemical reactions.
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We report the effective crystal growth for a unique single phase of spinel cobalt rhodium oxide (Co2RhO4) nanotubes via the electrospinning process combined with the thermal annealing process. In the spinel structure of the electrospun Co2RhO4 nanotubes, Co3+ cations and Rh3+ cations randomly occupy the octahedral sites, while the remaining half of the Co2+ cations occupy the centres of the tetrahedral sites as proved by microscopic and spectroscopic observations. Furthermore, electrospun spinel Co2RhO4 nanotubes exhibit excellent catalytic performances with the least positive onset potential, greatest current density, and low Tafel slope which are even better than those of the commercial Ir/C electrocatalyst for the oxygen evolution reaction (OER) in alkaline solution.

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