Tuning the Optical and Electrical Properties of Polymer‐Based Nanocomposites by Plasmon‐Induced Electromagnetic Field

Abstract

For nanocomposites composed of plasmonic nanocrystal and polymers, the plasmon‐induced electromagnetic field (EF) around the plasmonic nanocrystals can be used to change the dielectric environment around them, resulting in the optical and electrical properties of nanocomposites being adjustable. The electrical conductivities of ligand coated on plasmonic nanocrystal and polymer matrix play important roles in controlling the “local” and “overall” dielectric environment of nanocomposites under plasmon‐induced EF. The changes in the dielectric environment of nanocomposites are caused by the rearrangement of molecular chains of ligand and/or polymer matrix around the plasmonic nanocrystals. The optical properties of nanocomposites depend on the “local” and “overall” dielectric environment of nanocomposites, which show a significant change in the plasmon resonance wavelength (blueshift ≈10 nm) under plasmon‐induced EF. However, the electrical properties of nanocomposites depend only on the “overall” dielectric environment of the nanocomposite under plasmon‐induced EF. Nanocomposites are constructed in the conducting polymer matrix resulting in three orders of magnitude increase (from 4 × 10–14 to 10–10 s cm−1) in the electrical conductivity of nanocomposites under plasmon‐induced EF. Such plasmonic nanocrystal‐polymer nanocomposites with highly sensitive optical and electrical properties under external stimuli have potential applications in “electromagnetic field” or “photonic” sensors.

Silver nanocube dimer nanojunctions as plasmon-enhanced Raman sensors

“…Change the ligand coated on the bottom AgNC array by surface modification. For surface modification of HS-poly-p-TPA on the bottom AgNC array, dropping 1 mM of HS-poly-p-TPA (which was synthesized in a previous report 35 ) in toluene solution on PVP-coated AgNC arrays on a Si/glass substrate and incubated 8-10 min. And then AgNC arrays were washed with toluene.…”

“…Changing the dielectric environment by tuning the plasmon-induced electromagnetic field can be attributed to the configurational rearrangement of conducting polymers along the plasmon-induced electromagnetic field. 35 This suggested that the spacing between nanocrystals in the dimer nanojunction can theoretically be tuned by changing the configuration of the conducting polymer under the plasmon-induced electromagnetic field, which should tune the sensing performance of the dimer nanojunctions. Since there are no related reports discussing the effect of conducting polymer rearrangement under the plasmon-induced electromagnetic field on the sensing performance of plasmonic dimer nanojunctions, this makes the strategy of changing the sensing performance through molecular rearrangement worth exploring.…”