Jieun Lee

Single-photon emitters play an essential role in quantum technologies, including quantum computing and quantum communications. Atomic defects in hexagonal boron nitride ( h-BN) have recently emerged as new room-temperature single-photon emitters in solid-state systems, but the development of scalable and tunable h-BN single-photon emitters requires external methods that can control the emission energy of individual defects. Here, by fabricating van der Waals heterostructures of h-BN and graphene

Ferromagnetism in two-dimensional materials presents a promising platform for the development of ultrathin spintronic devices with advanced functionalities. Recently discovered ferromagnetic van der Waals crystals such as CrI3, readily isolated two-dimensional crystals, are highly tunable through external fields or structural modifications. However, there remains a challenge because of material instability under air exposure. Here, we report the observation of an air-stable and layer-dependent f

Color centers in two-dimensional hexagonal boron nitride (h-BN) have recently emerged as stable and bright single-photon emitters (SPEs) operating at room temperature. In this study, we combine theory and experiment to show that vacancy-based SPEs selectively form at nanoscale wrinkles in h-BN with its optical dipole preferentially aligned to the wrinkle direction. By using density functional theory calculations, we find that the wrinkle's curvature plays a crucial role in localizing vacancy-bas

A flexible and free standing conjugated microporous polymer (CMP) membrane was prepared using a polyvinylpyrrolidone (PVP) electrospun membrane as a template. The PVP nanofibers of the template membrane were coated with a thin layer of the CMP through the in situ Sonogashira-Hagihara coupling reaction of 1,3,5-triethynylbenzene and 1,4-diiodobenzene. The PVP nanofibers were removed by the solvent extraction to produce the CMP membrane, which retained the entangled fibrous structure of the templa

Silver grid printed on ITO film through EHD jet printing as a transparent conducting electrode improves electrochromic performances of soft ECDs.

Abstract Colour centres of hexagonal boron nitride ( h -BN) have been discovered as promising and practical single photon sources due to their high brightness and narrow spectral linewidth at room-temperature. In order to realize h -BN based photonic quantum communications, the ability to electrically activate the single photon fluorescence using an external electric field is crucial. In this work, we show the electrical switching of the photoluminescence from h -BN quantum emitters, enabled by

The electronic structures of perovskite ${\text{SrMn}}_{1\ensuremath{-}x}{\text{Mo}}_{x}{\text{O}}_{3}$ $(0\ensuremath{\le}x\ensuremath{\le}0.5)$ have been investigated by employing soft x-ray absorption spectroscopy (XAS). $\text{Mn}\text{ }2p$ XAS shows the systematic change in the valence states of Mn ions in ${\text{SrMn}}_{1\ensuremath{-}x}{\text{Mo}}_{x}{\text{O}}_{3}$ due to the substitution of hexavalent ${\text{Mo}}^{6+}(4{d}^{0})$ ions. With increasing $x$, the valence states and the s