Weiling Dong

Dartmouth College · Thayer School of Engineering

GeSn on Si has attracted much research interest due to its tunable direct bandgap for mid‐infrared applications. Recently, short‐range order (SRO) in GeSn alloys has been theoretically predicted, which profoundly impacts the band structure. However, characterizing SRO in GeSn is challenging. Guided by physics‐informed Poisson statistical analyses o...

GeSn on Si has attracted much research interest due to its tunable direct bandgap for mid-infrared applications. Recently, short-range order (SRO) in GeSn alloys has been theoretically predicted, which profoundly impacts the band structure. However, characterizing SRO in GeSn is challenging. Guided by physics-informed Poisson statistical analyses o...

Materials that exhibit large and rapid switching of their optical properties in the visible spectrum hold the key to color-changing devices. Antimony trisulfide (Sb 2 S 3 ) is a chalcogenide material that exhibits large refractive index changes of ~1 between crystalline and amorphous states. However, little is known about its ability to endure mult...

The objective of this paper is to understand the origin of the unusually large optical gap in amorphous chalcogenide phase change materials. The optical contrast between the crystalline and amorphous forms of phase‐change materials (PCM) is so marked as to make it ideal for data storage. Various explanations for this gap have been given, including,...

Hyperbolic metamaterials (HMMs) have emerged as a burgeoning field of research over the past few years as their dispersion can be easily engineered in different spectral regions using various material combinations. Even though HMMs have comparatively low optical loss due to a single resonance, the noble‐metal‐based HMMs are limited by their strong...

This work investigates the diffusion of metal atoms into phase change chalcogenides, which is problematic because it can destroy resonances in photonic devices. Interfaces between \(\hbox {Ge}_2\hbox {Sb}_2\hbox {Te}_5\) and metal layers were studied using X-ray reflectivity and reflectometry of metal–\(\hbox {Ge}_2\hbox {Sb}_2\hbox {Te}_5\) layere...

We demonstrate a facile method to fabricate Ag-Sb2S3 nanoporous plasmonic absorbers on plastic, crystalline, and glassy substrates. Our lithography-free method exploits the immiscibility of Ag and Sb2S3 to control the surface morphology of the absorbing structure. We experimentally and theoretically show that the nanoporous structure exhibits a hig...

The development of various plasmonic nanoporous materials have attracted much interest in different areas of research including bioengineering and biosensing because of their large surface area and versatile porous structure. Here, we introduce a novel technique for fabricating silver-stibnite nanoporous plasmonic films. Unlike conventional techniq...

This work investigates the problematic diffusion of metal atoms into phase change chalcogenides, which can destroy resonances in photonic devices. Interfaces between Ge2Sb2Te5 and metal layers were studied using X-ray reflectivity (XRR) and reflectometry of metal-Ge2Sb2Te5 layered stacks. The diffusion of metal atoms influences the crystallisation...

Light strongly interacts with structures that are of a similar scale to its wavelength; typically nanoscale features for light in the visible spectrum. However, the optical response of these nanostructures is usually fixed during the fabrication. Phase change materials offer a way to tune the properties of these structures in nanoseconds. Until now...

The objective of this paper is to demonstrate that Ag readily diffuses into Sb 2 S 3 and that electric fields can control the diffusion. Ag diffusion influences the crystallization temperature and electrical properties of Sb 2 S 3 . We studied the interface between Ag and Sb 2 S 3 using X-ray reflectivity and show that the Ag cations can be control...

The intense light–matter interaction of plasmonic metasurfaces provides an appealing platform for optical sensing. To date, most metasurface sensors are not spectrally tuned. Moreover, they operate in a total reflection mode, which complicates the optical setup. Transmissive tunable filters are therefore desirable. A mid‐infrared (M‐IR) tunable met...

The inherent narrowband surface plasmon resonance of metallic nanostructures was once thought to limit bandwidth of absorptance, yet recent demonstrations show that it can be harnessed using mechanisms like multiple resonances, impedance matching and slow-light modes to create broadband absorptance. However, in the visible region, realisation of ab...

Oxygen-doped germanium telluride phase change materials are proposed for high temperature applications. Up to 8 at.% oxygen is readily incorporated into GeTe, causing an increased crystallisation temperature and activation energy. The rhombohedral structure of the GeTe crystal is preserved in the oxygen doped films. For higher oxygen concentrations...

While Li–S batteries are poised to be the next generation high-density energy storage devices, low sulfur utilization and slow rate performance have limited their practical applications. Here, we report the synthesis of monodispersed S8 nanoparticles (NPs) with different diameter and the nanosize dependent kinetic characteristics of the correspondi...

The solid electrolyte interphase (SEI) that forms on electrodes largely defines the performances of lithium ion batteries (LIBs), such as cycling performance, shelf life, and safety. Additives in the electrolyte can modify the properties of the SEI and thus efficiently improve the performances of LIBs. However, the effects of additives on the mecha...

We report a sulfur-amine chemistry-based method to prepare multi-walled carbon nanotube-sulfur (MWNT-S) composites in a highly efficient and quantitative manner. The resulting MWNT-S composites exhibit excellent cycling stability at up to 400 cycles, with high sulfur loading. Developing this method also increases the number of research routes that...

We report the synthesis of ultrafine S nanoparticles with diameter 10 ~ 20 nm via a membrane-assisted precipitation technique. The S nanoparticles were then coated with conducting poly (3,4-ethylenedioxythiophene) (PEDOT) to form S/PEDOT core/shell nanoparticles. The ultrasmall size of S nanoparticles facilitates the electrical conduction and impro...

Ultrafine Sulfur Nanoparticles in Conducting Polymer Shell as Cathode Materials for High Performance Lithium/Sulfur Batteries

Si/poly(3,4-ethylenedioxythiophene) (PEDOT) core/shell nanowire arrays have been prepared by chemical etching of Si nanowires followed by vapor-phase polymerization of PEDOT as hybrid photoanodes for photoelectrochemical water-splitting. The PEDOT layer is employed as a multi-functional coating to prevent photocorrosion of Si nanowires, collect pho...