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Phase transitions in spin-crossover thin films probed by graphene transport measurements : towards smart heterostructures - Julien Dugay

Université de Valencia, Espagne

Future multifunctional hybrid devices might combine switchable molecules and 2D material-based devices.1 Spin-crossover (SCO) compounds are of particular interest in this context since they exhibit bistability and memory effects at room temperature while responding to numerous external stimuli.2–5

Atomically thin 2D materials such as graphene attract a lot of attention for their fascinating electrical, optical, and mechanical properties, but also for their reliability for room-temperature operations.6 Here, we demonstrate that thermally induced spin-state switching of SCO nanoparticle thin films can be monitored through the electrical transport properties of graphene lying underneath the films7. Model calculations indicate that the charge carrier scattering mechanism in graphene is sensitive to the spin-state dependence of the relative dielectric constants of the SCO nanoparticles.

This graphene sensor approach could be applied to a wide class of (molecular) systems with tunable electronic polarizabilities. More broadly, I will present how this concept will be extended to engineer changes in the electronic structure of conducting and semiconducting TMCs (MoS2, TaS2, NbSe2) by exploiting the structural and electronic changes of various SCO systems : (hybrid) SCO nanoparticles (Au@SCO ; SiO2@SCO), sublimable thermal/light- induced SCO molecular layers and Multi-layered SCO frameworks (containing pores able to select certain molecules that strongly affect the SCO).

1. Coronado, E., Galán-Mascarós, J. R., Gómez-García, C. J. & Laukhin, V.. Nature 408, 447–449 (2000)

2. Bousseksou, A., Molnár, G., Salmon, L. & Nicolazzi, W. Chem. Soc. Rev. 40, 3313–3335 (2011)

3. Dugay, J. et al. Adv. Mater. 27, 1288–1293 (2015)

4. Holovchenko, A., Dugay, J. et al. Adv. Mater. 28, 7228–7233 (2016)

5. Lefter, C. et al. Magnetochemistry 2, 18 (2016)

6. Geim, A. K. & Grigorieva, I. V. Van der Waals heterostructures. Nature 499, 419–425 (2013)

7. Dugay, J. et al. Nano Lett. 17, 186–193, (2017)


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