2, UARK, Fayetteville, Arkansas, United States
An optical phenomena based on the incident light absorption and transduction to the detectable thermal signal by plasmonic bimetallic Ag and Au nanocages (Ag@AuNCs) has been researched on free standing films. The photothermal response in the visible range (532 nm) is distinguishable. Specifically increasing the laser power to 100 mW led to visual burning of the free standing film (temperature increased greater than >150 °C). the molar concentration of the plasmonic Ag@AuNCs in polymer films is a primary factor that affects the photothermal dynamic response along with Ag@AuNCs distribution. This is supposed to result from the Ag@AuNCs assembled in a layer that leads to electromagnetic field enhancement. The unusual observation in polymer films is that the UV-visible spectra (extinction efficiency) and photothermal response (Tmax) do not rely on the content of the polymer and show a comparable (by value in magnitude) photothermal response at a different polymer composition at the same Ag@AuNCs concentration.
This work was supported in part by NSF ECCS-1006927, NSF CBET 1134222 and the University of Arkansas Foundation. UV-visible spectroscopy was supported by NSF EEC-1138248. The Arkansas Bio Nano Materials Characterization Facility is supported in part by the NSF. I thank Jeremy R. Dunklin, Samir V. Jenkins, Jingyi Chen and D. Keith Roper