Magnetic field induced cooperativity tuning in a Fe(II)-based hybrid spin crossover network grown on 2D surfaces

Hybrid nanostructures which are made of 2D architecture have potential applicability in many fields. While spin crossover (SCO) materials have bistability in spin states, their application is limited due to structural delicacy. Combining the flatness of 2D template and unique spin state transition property of SCO, we prepared a hybrid nanocomposite that can detect molecular spin transition at elevated temperatures. We choose chemically synthesized reduced graphene oxide (rGO) due to its plethora of available functional groups on the surface to bind SCO nanoparticle networks. Triazole ligand-based (Trz) Fe(II) SCO network is used due to its versatility. By tuning the coverage area of SCO nanoparticle’s network, 4 to 15 nm thickness variation is observed. The hybrid’s magnetic characterization reveals a field induced excited spin state transition with large thermal hysteresis (~ 40K) at high temperature. Due to interfacial substrate interaction, interchain coupling has enhanced, and ferromagnetic ordering is found in the heterostructure. Graphical abstract [Fe(Htrz) 2 (trz)]BF 4 -based nanoparticle network grown on rGO surface Inset shows spin state transition with large hysteretic behavior.