Geometric optics of gold nanoparticle-polydimethylsiloxane thin film systems

摘要

Interest in optical properties of plasmonic nanoparticles embedded in transparent dielectrics is growing due to potential uses in biomedicine, sustainable energy, and manufacturing. This work evaluates geometric optics in polymer thin films containing mono- or polydisperse gold nanoparticles (AuNP) using a compact linear algebraic sum. Reflection and transmission from polydimethylsiloxane (PDMS) films containing uniformly- or assymetrically-distributed monodisperse or polydisperse AuNPs decreased with AuNP morphological isotropy and particle density. In PDMS, monodisperse AuNPs increased optical attenuation linearly with gold content, while polydisperse AuNPs reduced from hydrogen tetrachloroaurate (TCA) increased optical attenuation in proportion to order-of-magnitude rises in gold content. Polydisperse AuNP concentrated asymmetrically at one film interface exhibited higher attenuation. Cumulative optical responses from AuNP-PDMS films paired with another film or reflective element were within 0.04 units on average from values predicted for transmission, reflection, or attenuation using linear algebra. These results support design of NP-containing dielectric films to integrate into biochemical, microelectromechanical, and optoelectronic devices and systems.