Broadband Spectroscopic Thermoacoustic Characterization of Single-Walled Carbon Nanotubes

Figure 1

(a) Photograph of the 2.7–3.1 GHz tunable microwave source. (b) Photograph of the 7–9 GHz tunable microwave source (traveling wave tube oscillator). The amplified microwave output was connected to a waveguide (WR-90 for 7–9 GHz), which was secured to the bottom of the imaging tank. (c) Photograph of imaging tank and single-element focused US transducer. Highlighted region: photograph of sample consisting of solutions of (1) semiconducting SWNTs, (2) metallic SWNTs, and (3) a baseline of deionized water. All solutions were imaged in 3 mm diameter polyolefin tubes. The solution of semiconducting SWNTs is darker than the solution of metallic SWNTs partly due to the higher nanoparticle concentration (300 ppm versus 100 ppm).

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