Partner: L. Pezzi


Recent publications
1.Pierini F., Guglielmelli A., Urbanek O., Nakielski P., Pezzi L., Buda R., Lanzi M., Kowalewski T.A., De Sio L., Thermoplasmonic‐activated hydrogel based dynamic light attenuator, Advanced Optical Materials, ISSN: 2195-1071, DOI: 10.1002/adom.202000324, Vol.8, No.12, pp.2000324-1-7, 2020
Abstract:

This work describes the morphological, optical, and thermo‐optical properties of a temperature‐sensitive hydrogel poly(N‐isopropylacrylamide‐co‐N‐isopropylmethacrylamide) [P(NIPAm‐co‐NIPMAm]) film containing a specific amount of gold nanorods (GNRs). The light‐induced thermoplasmonic heating of GNRs is used to control the optical scattering of an initially transparent hydrogel film. A hydrated P(NIPAm‐co‐NIPMAm) film is optically clear at room temperature. When heated to temperatures over 37 °C via light irradiation with a resonant source (λ = 810 nm) to the GNRs, a reversible phase transition from a swollen hydrated state to a shrunken dehydrated state occurs. This phenomenon causes a drastic and reversible change in the optical transparency from a clear to an opaque state. A significant red shift (≈30 nm) of the longitudinal band can also be seen due to an increased average refractive index surrounding the GNRs. This change is in agreement with an ad hoc theoretical model which uses a modified Gans theory for ellipsoidal nanoparticles. Morphological analysis of the composite film shows the presence of well‐isolated and randomly dispersed GNRs. Thermo‐optical experiments demonstrate an all‐optically controlled light attenuator (65% contrast ratio) which can be easily integrated in several modern optical applications such as smart windows and light‐responsive optical attenuators.

Keywords:

active plasmonics, gold nanorods, hydrogels, optical attenuators, optical transparency, plasmonic nanoparticles, polymers

Affiliations:
Pierini F.-IPPT PAN
Guglielmelli A.-University of Calabria (IT)
Urbanek O.-IPPT PAN
Nakielski P.-IPPT PAN
Pezzi L.-other affiliation
Buda R.-Institute of Physical Chemistry, Polish Academy of Sciences (PL)
Lanzi M.-University of Bologna (IT)
Kowalewski T.A.-IPPT PAN
De Sio L.-Sapienza University of Rome (IT)