MXene on Spin State Switching of Spin Crossover Molecular Thin Films*

Spin crossover (SCO) molecules are transition metal coordination complexes that exhibit a bistability between a low spin and a high spin state, and they can be switched between these two states via an external stimulus, such as light, temperature, pressure and electric field. Their unique properties make them intriguing candidates for next-generation molecular-based electronic devices. In the case of very thin SCO molecular films, the functionality of the deposited molecules can be significantly affected by the substrate-molecule interaction. While some non-metallic substrates appear to be promising for use in SCO molecular-based devices, metallic substrates including gold and copper tend to suppress changes in the spin state of the deposited SCO molecules near the interface. In this work, we study how the behavior of SCO molecules, specifically [Fe(H₂B(pz)₂)₂(bipy)], are affected when they are in the vicinity of a thin layer of  MXene class of 2D materials Ti₃C₂. In particular, Ti₃C₂ MXene exhibits metallic electrical conductivity. Various techniques were utilized to analyze the quality of fabricated Ti₃C₂ thin films and electronic transport measurements show that the conductance of the [Fe(H₂B(pz)₂)₂(bipy)] SCO molecules is enhanced.