Effect of nanostructuration on the spin crossover transition in crystalline ultrathin films

DOI: 10.1039/C8SC04935A

Authors: Victor Rubio-Gimenez (Universitat de València) , Carlos Bartual-Murgui (Universitat de València) , Marta Galbiati (Universitat de València) , Alejandro Núñez-López (Universitat de València) , Javier Castells-Gil (Universitat de València) , Benoit Quinard (CNRS, Thales, University Paris Sud, Université Paris-Saclay) , Pierre Seneor (CNRS, Thales, University Paris Sud, Université Paris-Saclay) , Edwige Otero (Synchrotron SOLEIL) , Philippe Ohresser (Synchrotron SOLEIL) , Andrés Cantarero (Universitat de València) , Eugenio Coronado (Universitat de València) , José Antonio Real (Universitat de València) , Richard Mattana (CNRS, Thales, University Paris Sud, Université Paris-Saclay) , Sergio Tatay (Universitat de València) , Carlos Martí-Gastaldo (Universitat de València)
Co-authored by industrial partner: No

Type: Journal Paper
Journal: Chemical Science , VOL 346

State: Published (Approved)
Published: February 2019
Diamond Proposal Number(s): 14495

Abstract: Mastering the nanostructuration of molecular materials onto solid surfaces and understanding how this process affects their properties are of utmost importance for their integration into solid-state electronic devices. This is even more important for spin crossover (SCO) systems, in which the spin transition is extremely sensitive to size reduction effects. These bi-stable materials have great potential for the development of nanotechnological applications provided their intrinsic properties can be successfully implemented in nanometric films, amenable to the fabrication of functional nanodevices. Here we report the fabrication of crystalline ultrathin films (<1–43 nm) of two-dimensional Hofmann-type coordination polymers by using an improved layer-by-layer strategy and a close examination of their SCO properties at the nanoscale. X-ray absorption spectroscopy data in combination with extensive atomic force microscopy analysis reveal critical dependence of the SCO transition on the number of layers and the microstructure of the films. This originates from the formation of segregated nanocrystals in early stages of the growth process that coalesce into a continuous film with an increasing number of growth cycles for an overall behaviour reminiscent of the bulk. As a result, the completeness of the high spin/low spin transition is dramatically hindered for films of less than 15 layers revealing serious limitations to the ultimate thickness that might be representative of the performance of the bulk when processing SCO materials as ultrathin films. This unprecedented exploration of the particularities of the growth of SCO thin films at the nanoscale should encourage researchers to put a spotlight on these issues when contemplating their integration into devices.

Subject Areas: Materials, Chemistry, Physics


Instruments: I07-Surface & interface diffraction

Other Facilities: Soleil; ALBA

Added On: 22/03/2019 15:55

Documents:
jlkjlj98.pdf

Discipline Tags:

Surfaces Physics Electronics Chemistry Materials Science Chemical Engineering interfaces and thin films Engineering & Technology Nanoscience/Nanotechnology

Technical Tags:

Diffraction Grazing Incidence X-ray Diffraction (GIXD)