Solid-state superionic stamping with silver iodide-silver metaphosphate glass

Low temperature conductivity and ion dynamics in silver iodide-silver metaphosphate glasses

Silver iodide-silver metaphosphate glasses xAgI·(1 - x)AgPO₃ (x = 0.3, 0.4, and 0.5) have been prepared using the usual melt quenching method. Differential scanning calorimetry has been used to determine the glass transition temperature of the samples. Impedance spectroscopy spanning wide temperature (20 K to 200 K) and frequency (10^-1 Hz to 10⁶ Hz) ranges has been employed to investigate the ion dynamics. At high temperatures, below the glass transition temperature and down to around 120 K, the dynamics show the usual behavior of dc and dispersed conductivity due to the random and correlated motion of the ions. The dc conductivity of the glasses varies dramatically and it increases with the AgI content as expected. At the lowest temperatures investigated, however, the conductivity of the glasses was indistinguishable. Hence, the low temperature dynamics are identical irrespective of the amount of AgI and the structure of the glass. In addition, a nearly constant loss behavior, independent of the temperature and composition, was attained at the lowest temperatures.

Optical and electrical characterizations of multifunctional silver phosphate glass and polymer-based optical fibers

In recent years, the fabrication of multifunctional fibers has expanded for multiple applications that require the transmission of both light and electricity. Fibers featuring these two properties are usually composed either of a single material that supports the different characteristics or of a combination of different materials. In this work, we fabricated (i) novel single-core step-index optical fibers made of electrically conductive AgI-AgPO₃-WO₃ glass and (ii) novel multimaterial fibers with different designs made of AgI-AgPO₃-WO₃ glass and optically transparent polycarbonate and poly (methyl methacrylate) polymers. The multifunctional fibers produced show light transmission over a wide range of wavelengths from 500 to 1000 nm for the single-core fibers and from 400 to 1000 nm for the multimaterial fibers. Furthermore, these fibers showed excellent electrical conductivity with values ranging between 10^-3 and 10^-1 S·cm^-1 at room temperature within the range of AC frequencies from 1 Hz to 1 MHz. Multimodal taper-tipped fibre microprobes were then fabricated and were characterized. This advanced design could provide promising tools for in vivo electrophysiological experiments that require light delivery through an optical core in addition to neuronal activity recording.

Electrochemical direct writing and erasing of silver nanostructures on phosphate glass using atomic force microscopy

This paper reports a liquid-free, mask-less electrochemical direct-write lithographic technique using an atomic force microscopy (AFM) probe for writing silver nanostructures in minutes on an optically transparent substrate. Under ambient conditions, silver is locally and controllably extracted to the surface of superionic (AgI)_0.25 (AgPO₃)_0.75 glass by bringing a conductive AFM probe tip in contact with it, biasing the probe with a negative voltage, and regulating the resulting current. The growth mechanism of the resulting nanostructure is explored by extracting silver with a stationary AFM tip on the surface of the silver. A moving tip was then used to produce continuous lines, solid films and discrete dots of silver by implementing continuous and pulsed current writing approaches. The line dimensions depend on writing speed and current flowing in the electrochemical circuit, while the size and spacing of the dots depend on the parameters (magnitude, duration and frequency) of the current pulses and the writing speed of the AFM tip. Line-widths in the ∼100 nm range are demonstrated. Our investigation also shows that a threshold potential must be overcome to be able to draw and reduce silver ions on the glass surface. When polarity between the electrodes is reversed, the patterned silver ionizes back into the glass, thus offering the capability to erase and rewrite Ag patterns on the glass surface.