Plasmonic Terahertz Devices and Sensors Based on Carbon Electronics

Abstract

Tunable terahertz (THz) photonic devices are imperative in a wide range of applications ranging from THz signal modulation to molecular sensing. One of the currently prevailing methods is based on arrays of metallic or dielectric resonators integrated with functional materials in response to an external stimulus, in which for the purpose of sensing the external stimuli may introduce inadvertent undesirable effects into the target samples to be measured. Here we developed an alternative approach by postprocessing nanothickness macro-assembled graphene (nMAG) films with widely tunable THz conductivity, enabling versatile solid-state THz devices and sensors, showing multifunctional nMAG-based applications. The THz conductivities of free-standing nMAGs showed a broad range from 1.2 × 103 S/m in reduced graphene oxide before annealing to 4.0 × 106 S/m in a nMAG film annealed at 2800 °C. We fabricated nMAG/dielectric/metal and nMAG/dielectric/nMAG THz Salisbury absorbers with broad reflectance ranging from 0% to 80%. The highly conductive nMAG films enabled THz metasurfaces for sensing applications. Taking advantage of the resonant field enhancement arising from the plasmonic metasurface structures and the strong interactions between analyte molecules and nMAG films, we successfully detected diphenylamine with a limit of detection of 4.2 pg. Those wafer-scale nMAG films present promising potential in high-performance THz electronics, photonics, and sensors.

Calcium‐Based Metal‐Organic Framework: Detection and Idiosyncratic Removal of Copper by Nano‐Particle Deposition

“…Similarly, in the case of N 1s, [52,53] the peak at 398.78 eV corresponds to the C=N bond, and in the case of the O 1s spectrum, the peaks at 531.48 eV and 533.08 eV correspond to the C−O and C=O bond, [54] respectively. Moreover, from the deconvolution spectrum of Ca 2p, two peaks at 350.98 eV [55] and 347.48 eV could be attributed to 2p 1/2 and 2p 3/2, respectively [56] . The band at 1644 cm −1 , 1618 cm −1 , and 1297 cm −1 in the FTIR spectrum of CaMOF@LSB (Figure S7) can be attributed to C=O of the carbonyl functional group, C=N of the imine group and C−O bond, respectively.…”