Investigation of the film growth and physical properties of thin molecular layers of the spin crossover compound Fe(HB(tz)3)2 / Alin,Ciprian Bas  

Public ISBD Titre : Investigation of the film growth and physical properties of thin molecular layers of the spin crossover compound Fe(HB(tz)3)2 Type de document : texte imprimé Auteurs : Alin,Ciprian Bas, Auteur ; Gabor Molnar, Directeur de la recherche ; Christophe Thibault, Directeur de la recherche Langues : Anglais (eng) Tags : SPIN CROSSOVER  THIN FILMS  LUMINESCENCE  ATOMIC FORCE MICROSCOPY Résumé : "The recent progress in the nanoscale synthesis and organization of molecular spin crossover (SCO) materials allowed the elaboration of a variety of molecular nano-objects (nanoparticles, thin films, nanopatterns, nanoscale assemblies, etc.) exhibiting SCO properties. These new nanometer-sized materials offer the appealing possibility to exploit their switchable properties at the nanometric scale and open the way for the integration and implementation of SCO in various applications (sensors, actuators, information processing and storage devices). Despite the considerable progress accomplished, numerous challenges remain to be addressed. Notably, it appears crucial to enlarge considerably the portfolio of SCO complexes displaying robust, near room temperature switching properties. Turning these compounds into high quality nanomaterials calls also for rigorous material science studies along with fundamental understanding of the role of surface/interface properties on the desired functionality. Of particular importance would be to clarify if the robustness of the SCO phenomenon can meet the stringent requirements for 'real world' applications. In this context, this thesis work describes the growth and physical properties of nanometric thin films of the SCO compound Fe(HB(tz)3)2 (tz = 1,2,4-triazol-1-yl). Notably we describe the vacuum deposition of this compound by thermal evaporation and we show that a straightforward solvent vapor annealing process allows for obtaining high quality, nanometric thin films exhibiting SCO near room temperature. We reveal also an unprecedented and unexpected reversibility of the SCO in these films over numerous switching cycles (> million) as well as its thermal, environmental and processing stability. This exceptional stability of the SCO allowed us (1) to carry out a careful investigation of finite size effects for different film thicknesses as well as (2) to implement quantitative atomic force microscopy imaging of the films with particular emphasis on the analysis of mechanical properties (Young's modulus, loss tangent, etc.). In view of high spatial resolution near-field optical studies, we also developed hybrid luminescent - SCO films consisting of a combination of Fe(HB(tz)3)2 and Ir(ppy)3 (ppy = 2-phenylpyridine) molecules and demonstrated the luminescence modulation by the SCO." Document : Thèse de Doctorat Etablissement_delivrance : Université Toulouse 3 Ecole_doctorale : Sciences de la Matière (SdM) (Toulouse) Domaine : Physique En ligne : https://theses.hal.science/tel-02535306 Investigation of the film growth and physical properties of thin molecular layers of the spin crossover compound Fe(HB(tz)3)2 [texte imprimé] / Alin,Ciprian Bas, Auteur ; Gabor Molnar, Directeur de la recherche ; Christophe Thibault, Directeur de la recherche . - [s.d.]. Langues : Anglais (eng) Tags : SPIN CROSSOVER  THIN FILMS  LUMINESCENCE  ATOMIC FORCE MICROSCOPY Résumé : "The recent progress in the nanoscale synthesis and organization of molecular spin crossover (SCO) materials allowed the elaboration of a variety of molecular nano-objects (nanoparticles, thin films, nanopatterns, nanoscale assemblies, etc.) exhibiting SCO properties. These new nanometer-sized materials offer the appealing possibility to exploit their switchable properties at the nanometric scale and open the way for the integration and implementation of SCO in various applications (sensors, actuators, information processing and storage devices). Despite the considerable progress accomplished, numerous challenges remain to be addressed. Notably, it appears crucial to enlarge considerably the portfolio of SCO complexes displaying robust, near room temperature switching properties. Turning these compounds into high quality nanomaterials calls also for rigorous material science studies along with fundamental understanding of the role of surface/interface properties on the desired functionality. Of particular importance would be to clarify if the robustness of the SCO phenomenon can meet the stringent requirements for 'real world' applications. In this context, this thesis work describes the growth and physical properties of nanometric thin films of the SCO compound Fe(HB(tz)3)2 (tz = 1,2,4-triazol-1-yl). Notably we describe the vacuum deposition of this compound by thermal evaporation and we show that a straightforward solvent vapor annealing process allows for obtaining high quality, nanometric thin films exhibiting SCO near room temperature. We reveal also an unprecedented and unexpected reversibility of the SCO in these films over numerous switching cycles (> million) as well as its thermal, environmental and processing stability. This exceptional stability of the SCO allowed us (1) to carry out a careful investigation of finite size effects for different film thicknesses as well as (2) to implement quantitative atomic force microscopy imaging of the films with particular emphasis on the analysis of mechanical properties (Young's modulus, loss tangent, etc.). In view of high spatial resolution near-field optical studies, we also developed hybrid luminescent - SCO films consisting of a combination of Fe(HB(tz)3)2 and Ir(ppy)3 (ppy = 2-phenylpyridine) molecules and demonstrated the luminescence modulation by the SCO." Document : Thèse de Doctorat Etablissement_delivrance : Université Toulouse 3 Ecole_doctorale : Sciences de la Matière (SdM) (Toulouse) Domaine : Physique En ligne : https://theses.hal.science/tel-02535306

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