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Anomalous Light-Induced Spin-State Switching for Iron(II) Spin-Crossover Molecules in Direct Contact with Metal Surfaces |
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| Authors: | Dr. Luqiong Zhang Dr. Yongfeng Tong Massine Kelai Dr. Amandine Bellec Dr. Jérôme Lagoute Dr. Cyril Chacon Dr. Yann Girard Dr. Sylvie Rousset Dr. Marie-Laure Boillot Dr. Eric Rivière Prof. Talal Mallah Dr. Edwige Otero Dr. Marie-Anne Arrio Dr. Philippe Sainctavit Prof. Vincent Repain |
| Affiliation: | 1. Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France These authors contributed equally to this work.;2. Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, 75013 Paris, France These authors contributed equally to this work.;3. Université de Paris, Laboratoire Matériaux et Phénomènes Quantiques, CNRS, 75013 Paris, France;4. Institut de Chimie Moléculaire et des Matériaux d'Orsay, Univ Paris Sud, Université Paris-Saclay, CNRS, UMR 8182, 91405 Orsay Cedex, France;5. Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, 91192 Gif sur Yvette, France;6. Institut de Minéralogie, de Physique des Matériaux et, de Cosmochimie, CNRS UMR7590, Sorbonne Université, MNHN, 75252 Paris Cedex 5, France |
| Abstract: | Light-induced spin-state switching is one of the most attractive properties of spin-crossover materials. In bulk, low-spin (LS) to high-spin (HS) conversion via the light-induced excited spin-state trapping (LIESST) effect may be achieved with a visible light, while the HS-to-LS one (reverse-LIESST) requires an excitation in the near-infrared range. Now, it is shown that those phenomena are strongly modified at the interface with a metal. Indeed, an anomalous spin conversion is presented from HS state to LS state under blue light illumination for FeII spin-crossover molecules that are in direct contact with metallic (111) single-crystal surfaces (copper, silver, and gold). To interpret this anomalous spin-state switching, a new mechanism is proposed for the spin conversion based on the light absorption by the substrate that can generate low energy valence photoelectrons promoting molecular vibrational excitations and subsequent spin-state switching at the molecule–metal interface. |
| Keywords: | ferrous ion complexes light conversion monolayer spin-crossover X-ray absorption |