Suspensions of Semiconducting Nanoparticles in Nafion for Transient Spectroscopy and Terahertz Photoconductivity Measurements

The characterization of emerging materials is crucial for the experimentally driven design of next-generation technologies. We describe a cost- and time-effective method for suspending nanoparticles and other photoactive materials in Nafion for transient spectroscopy and time-resolved terahertz (THz) photoconductivity measurements. Nafion is an ideal suspension matrix because it has high transparency throughout the UV/vis/near-IR and THz regions of the spectrum. Suspensions of nanoparticles in Nafion require only small amounts of sample (<5 mg) and can be prepared and deposited in ∼1 h. The suspension is well-suited for transient THz measurements, which can be used to determine the photoconductivity spectrum of the embedded nanoparticles. In this work, we used silicon nanoparticles as a model material to demonstrate the efficacy of Nafion suspensions for transient THz spectroscopy. This methodology can be used for rapid and cost-effective measurements of emerging materials such as solar materials, electrocatalysts, and nanomaterials.