skip to main content
US FlagAn official website of the United States government
dot gov icon
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
https lock icon
Secure .gov websites use HTTPS
A lock ( lock ) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.


Search for: All records

Creators/Authors contains: "Hurt, Robert"

Note: When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external site maintained by the publisher. Some full text articles may not yet be available without a charge during the embargo (administrative interval).
What is a DOI Number?

Some links on this page may take you to non-federal websites. Their policies may differ from this site.

  1. Solid state lithium metal batteries using garnet solid electrolytes such as LLZTO promise substantial improvements in energy density and safety. However, practical implementation is hindered by lithium dendrite penetration at high current densities. Recent work shows that internal electrochemically induced mechanical stresses are large enough to propagate lithium dendrites and subsequently fracture solid electrolytes. This study builds on this understanding and demonstrates that stress‐driven dendrite propagation can be controlled via deflection at weakly bonded internal interfaces. This approach, based on a fracture‐mechanics analysis of multilayered composites, is investigated with a variety of interlayer materials that are embedded into LLZTO. The viability and effectiveness of dendrite deflection are most clearly evident with reduced graphene oxide where the critical current density increased from 0.6 to 3.8 mA / cm2. In this material, both the weak interface with LLZTO and the mixed ionic–electronic conducting nature of the interlayer appear to contribute to the improved performance. Additional insight into the mechanics of multilayered electrolytes is also obtained with finite element modeling. The overall results present a promising proof‐of‐concept demonstration along with important generalized design guidelines for creating multilayered solid electrolyte architectures that can enable high‐performance solid‐state batteries. 
    more » « less
  2. Wrinkled graphene coatings are engineered to fulfill multiple functions desired for ultrathin gloves that prevent human exposure to chemical toxicants. 
    more » « less
  3. Microfabrication using nano‐ to micron‐sized building blocks holds a great potential for applications in next‐generation electronics, optoelectronics, and advanced materials. However, traditional methods like chemical vapor deposition and molecular beam epitaxy require highly controlled environments and specialized equipment, limiting scalability and precision. To address these challenges, a single‐laser platform is presented for selective tweezing and immobilization of colloids (STIC) that integrates particle manipulation, assembly, and stabilization in one system. STIC utilizes a femtosecond laser at ultra‐low power for precise, contact‐free optical manipulation of colloids without material damage. At higher power, the same laser enables two‐photon polymerization (TPP) to immobilize colloids securely in their intended positions. Using STIC, the assembly of 3D structures from dielectric beads to patterned arrangements of transition metal dichalcogenides (TMDs e.g., MoS2) is demonstrated. Also a TPP‐fabricated handle as an intermediate support is incorporated which significantly enhances the optical tweezing efficiency of TMDs. The single‐laser design eliminates the need for dual‐laser systems, simplifying optical alignment, reducing heat damage, and improving efficiency. Additionally, it is shown that STIC supports direct multiphoton imaging forin situinspection during fabrication. This work establishes a versatile, scalable optical platform for high‐precision microstructure fabrication, offering a pathway to overcome current limitations in micro‐ and nanomanufacturing. 
    more » « less
  4. Bacterial response to two-dimensional nanomaterials is dependent on the type and concentration of the material and the growth stage of the bacteria. 
    more » « less
  5. MoS2nanosheets in metallic 1T-phase enhance the electrical conductivity of fibrin hydrogels and show programmable bioresorption rates and pathways. 
    more » « less
  6. Graphene-based materials are being developed for a variety of wearable technologies to provide advanced functions that include sensing; temperature regulation; chemical, mechanical, or radiative protection; or energy storage. We hypothesized that graphene films may also offer an additional unanticipated function: mosquito bite protection for light, fiber-based fabrics. Here, we investigate the fundamental interactions between graphene-based films and the globally important mosquito species, Aedes aegypti , through a combination of live mosquito experiments, needle penetration force measurements, and mathematical modeling of mechanical puncture phenomena. The results show that graphene or graphene oxide nanosheet films in the dry state are highly effective at suppressing mosquito biting behavior on live human skin. Surprisingly, behavioral assays indicate that the primary mechanism is not mechanical puncture resistance, but rather interference with host chemosensing. This interference is proposed to be a molecular barrier effect that prevents Aedes from detecting skin-associated molecular attractants trapped beneath the graphene films and thus prevents the initiation of biting behavior. The molecular barrier effect can be circumvented by placing water or human sweat as molecular attractants on the top (external) film surface. In this scenario, pristine graphene films continue to protect through puncture resistance—a mechanical barrier effect—while graphene oxide films absorb the water and convert to mechanically soft hydrogels that become nonprotective. 
    more » « less
  7. There is great interest in exploiting van der Waals gaps in layered materials as confinement reaction vessels to template the synthesis of new nanosheet structures. The gallery spaces in multilayer graphene oxide, for example, can intercalate hydrated metal ions that assemble into metal oxide films during thermal oxidation of the sacrificial graphene template. This approach offers limited control of structure, however, and does not typically lead to 2D atomic-scale growth of anisotropic platelet crystals, but rather arrays of simple particles directionally sintered into porous sheets. Here, a new graphene-directed assembly route is demonstrated that yields fully dense, space-filling films of tiled metal oxide platelet crystals with tessellated structures. The method relies on colloidal engineering to produce a printable “metallized graphene ink” with accurate control of metal loading, grain size/porosity, composition, and micro/nanomorphologies, and is capable of achieving higher metal–carbon ratio than is possible by intercalation methods. These tiled structures are sufficiently robust to create free standing papers, complex microtextured films, 3D shapes, and metal oxide replicas of natural biotextures. 
    more » « less