The Interplay Between Surface Plasmon Resonance and Switching Properties in Gold@Spin Crossover Nanocomposites

Rod‐like gold nanoparticles are directly embedded in a 1D‐polymeric spin crossover (SCO) material leading to singular Au@SCO nanohybrid architectures. The resulting architectures are designed to promote a synergetic effect between ultrafast spin‐state photoswitching and photothermal properties of plasmonic nanoparticles. This synergy is evidenced by the strong modulation of the surface plasmon resonance of the gold nanorods through the spin‐state switching of the SCO component and also the strong enhancement of the photoswitching efficiency compared to pure SCO particles. This remarkable synergy results from the large modulation of the dielectric properties of the SCO polymer upon its thermal switching and the enhancement of the heating of these hybrid nanostructures upon excitation of the surface plasmon resonance of the gold nanorods.