Thermoresponsive nanoparticles + plasmonic nanoparticles = photoresponsive heterodimers: facile synthesis and sunlight-induced reversible clustering.

Magnetic nanoparticles functionalized with thermoresponsive polymers become photoresponsive when attached to plasmonic nanoparticles to form heterodimers. Under solar illumination, the plasmonic particles absorb sunlight and induce localized heating, causing collapse of the thermoresponsive polymer chain and clustering of the dimers that facilitate magnetic separation.