An official website of the United States government
Abstract Subwavelength optical resonators with spatiotemporal control of light are essential to the miniaturization of optical devices. In this work, chemically synthesized transition metal dichalcogenide (TMDC) nanowires are exploited as a new type of dielectric nanoresonators to simultaneously support pronounced excitonic and Mie resonances. Strong light–matter couplings and tunable exciton polaritons in individual nanowires are demonstrated. In addition, the excitonic responses can be reversibly modulated with excellent reproducibility, offering the potential for developing tunable optical nanodevices. Being in the mobile colloidal state with highly tunable optical properties, the TMDC nanoresonators will find promising applications in integrated active optical devices, including all‐optical switches and sensors.
more »
« less
Near‐Field Nanoimaging of Colloidal Transition Metal Dichalcogenide Waveguides
Abstract Bulk transition metal dichalcogenide (TMDC) nanostructures are regarded as promising material candidates for integrated photonics due to their high refractive index at the near‐infrared wavelengths. In this work, colloidal TMDC waveguides with tailorable dimensions are prepared by a scalable synthetic approach. The optical waveguiding properties of colloidal nanowires are studied by the near‐field nanoimaging technique. In addition to dependence on thickness and wavelength, the excitonic responses and resultant waveguide modes in TMDC nanowires can be modulated by the environmental temperature. With the high‐throughput production and tunable optical properties, colloidal TMDC nanowires highlight the potential for active optical components and integrated photonic devices.
more »
« less
- PAR ID:
- 10508808
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Functional Materials
- Volume:
- 34
- Issue:
- 21
- ISSN:
- 1616-301X
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Unlike noble metals, refractory plasmonic materials can maintain resilient and attractive optical properties even at comparatively extreme temperatures and high current densities. One refractory plasmonic material of interest is TiN, which exhibits an extremely high melting temperature of about 3000 K and noble-metal-like optical properties in the visible and near-infrared regime. Using lithographically fabricated TiN nanowires and leveraging their ability to host plasmon modes, we have examined plasmonic photothermal heating and photothermoelectric response whose anisotropy and magnitude depend on the width of the nanowires. The photothermoelectric response is consistent with changes in the Seebeck coefficient where the wire fans out to wider contact pads. Upon electrically biasing the structures, Joule heating of the TiN wires can produce detectable thermal emission within the visible and near-IR range, with emission intensity growing rapidly with increasing bias. This emission is consistent with local temperatures exceeding 2000 K, as expected from a finite element model of the Joule heating.more » « less
-
Abstract Transition metal dichalcogenide (TMDCs) alloys could have a wide range of physical and chemical properties, ranging from charge density waves to superconductivity and electrochemical activities. While many exciting behaviors of unary TMDCs have been demonstrated, the vast compositional space of TMDC alloys has remained largely unexplored due to the lack of understanding regarding their stability when accommodating different cations or chalcogens in a single‐phase. Here, a theory‐guided synthesis approach is reported to achieve unexplored quasi‐binary TMDC alloys through computationally predicted stability maps. Equilibrium temperature–composition phase diagrams using first‐principles calculations are generated to identify the stability of 25 quasi‐binary TMDC alloys, including some involving non‐isovalent cations and are verified experimentally through the synthesis of a subset of 12 predicted alloys using a scalable chemical vapor transport method. It is demonstrated that the synthesized alloys can be exfoliated into 2D structures, and some of them exhibit: i) outstanding thermal stability tested up to 1230 K, ii) exceptionally high electrochemical activity for the CO2reduction reaction in a kinetically limited regime with near zero overpotential for CO formation, iii) excellent energy efficiency in a high rate Li–air battery, and iv) high break‐down current density for interconnect applications. This framework can be extended to accelerate the discovery of other TMDC alloys for various applications.more » « less
-
Abstract The highly intricate structures of biological systems make the precise probing of biological behaviors at the cellular‐level particularly difficult. As an advanced toolset capable of exploring diverse biointerfaces, high‐aspect‐ratio nanowires stand out with their unique mechanical, optical, and electrical properties. Specifically, semiconductor nanowires show much promise in their tunability and feasibility for synthesis and fabrication. Thus far, semiconductor nanowires have shown favorable results in deciphering biological communications and translating this cellular language through the nanowire‐based biointerfaces. In this perspective, the synthesis and fabrication methods for different kinds of nanowires and nanowire‐based structures are first surveyed. Next, several cellular‐level nanowire‐enabled applications in biophysical dynamics probing, physiological or biochemical sensing, and biological activity modulation are highlighted. Then, the progress of functionalized nanowires in drug delivery and bioenergy production is reviewed. Finally, the current limitations of nanowires and an outlook into the next generation of nanowire‐based devices at the biointerfaces are concluded.more » « less
-
Layered metal-halide perovskites, or two-dimensional perovskites, can be synthesized in solution, and their optical and electronic properties can be tuned by changing their composition. We report a molecular templating method that restricted crystal growth along all crystallographic directions except for [110] and promoted one-dimensional growth. Our approach is widely applicable to synthesize a range of high-quality layered perovskite nanowires with large aspect ratios and tunable organic-inorganic chemical compositions. These nanowires form exceptionally well-defined and flexible cavities that exhibited a wide range of unusual optical properties beyond those of conventional perovskite nanowires. We observed anisotropic emission polarization, low-loss waveguiding (below 3 decibels per millimeter), and efficient low-threshold light amplification (below 20 microjoules per square centimeter).more » « less
