1. Space Charge-Limited Current Transport Mechanism in Crossbar Junction Embedding Molecular Spin Crossovers
- Author
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Maria Fittipaldi, Alberto Cini, Enrico Berretti, Matteo Atzori, Patrick Rosa, Lorenzo Poggini, Mathieu Gonidec, Giuseppe Cucinotta, Alessandro Lavacchi, Niccolò Giaconi, Aleksandr I. Chumakov, Rudolf Rüffer, Matteo Mannini, Department of Chemistry 'Ugo Schiff', Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), National Interuniversity Consortium of Materials Science and Technology (INSTM ), Departement of Physics and Astronomy, Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Istituto di Chimica dei Composti Organometallici (ICCOM), Consiglio Nazionale delle Ricerche (CNR), European Synchrotron Radiation Facility (ESRF), and We thank Prof. Gabriele Spina at the University of Florence for his help with Mössbauer data analysis. We thank the European Synchrotron Radiation Facility (Grenoble, France) for provision of synchrotron radiation resources at the Nuclear Resonance beamline ID18 during CH-4909 beamtime. We are grateful to Jean-Philippe Celse at the ESRF for providing assistance in using beamline ID18. This work was supported by Fondazione CR Firenze (through Spin-E project no. 2017.0730 coordinated by M.M. and through the grant for M.F., project no. 2016.1104), the Italian MIUR ('Progetto Dipartimenti di Eccellenza 2018-2022, ref. B96C1700020008' allocated to the Department of Chemistry 'Ugo Schiff'), the French National Research Agency (ANR) Investment for the Future Programme IdEx Bordeaux (ANR-10-IDEX-03-02, grants for M.G. and L.P.), and FEMTOMAT project (ANR-13-BS04-002, P.R.). A.L. and E.B. acknowledge 'Fondazione Cassa di Risparmio di Firenze' and Regione Toscana for the project FELIX (POR FESR 2014-2020, grant no. 6455) for financial support given for the acquisition of the TESCAN GAIA3 electron microscope.
- Subjects
molecular spintronics ,Materials science ,Spin states ,Spin transition ,molecular magnetism ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,spin crossover ,Spin crossover ,Phase (matter) ,General Materials Science ,Thin film ,Spin-½ ,Molecular switch ,Condensed matter physics ,[CHIM.MATE]Chemical Sciences/Material chemistry ,synchrotron Mössbauer spectroscopy ,FIB-STEM ,021001 nanoscience & nanotechnology ,Space charge ,0104 chemical sciences ,hybrid device ,transport measurements ,0210 nano-technology ,Research Article - Abstract
International audience; Spin crossover complexes are among the most studied classes of molecular switches and have attracted considerable attention for their potential technological use as active units in multifunctional devices. A fundamental step toward their practical implementation is the integration in macroscopic devices adopting hybrid vertical architectures. First, the physical properties of technological interest shown by these materials in the bulk phase have to be retained once they are deposited on a solid surface. Herein, we describe the study of a hybrid molecular inorganic junction embedding the spin crossover complex [Fe(qnal)2] (qnal = quinoline-naphthaldehyde) as an active switchable thin film sandwiched within energy-optimized metallic electrodes. In these junctions, developed and characterized with the support of state of the art techniques including synchrotron Mössbauer source (SMS) spectroscopy and focused-ion beam scanning transmission electron microscopy, we observed that the spin state conversion of the Fe(II)-based spin crossover film is associated with a transition from a space charge-limited current (SCLC) transport mechanism with shallow traps to a SCLC mechanism characterized by the presence of an exponential distribution of traps concomitant with the spin transition temperature.
- Published
- 2020