Room temperature optoelectronic devices operating with spin crossover nanoparticles

Abstract

Molecular systems can exhibit multi-stimuli switching of their properties, with spin crossover materials having unique magnetic transition triggered by temperature and light, among others. Light-induced room temperature operation is however...

Photo‐Thermal Switching of Individual Plasmonically Activated Spin Crossover Nanoparticle Imaged by Ultrafast Transmission Electron Microscopy

“…In this study, we focus our attention on triazole-based SCO nanoparticles which are widely studied for implementation in devices. [5,8,13] They are built from a 1D coordination polymer made of Fe(II) metal ionic switchable sites linked together by bridging triazole ligands to form linear chains separated by counter-anions. [47] The [Fe(Htrz) 2 trz](BF 4 ) is probably the most studied compound since large hysteresis loops can be observed above room temperature [48,49] and at the nanoscale.…”

“…In the crystals, this local volume change at the metal site propagates through the whole material by intermolecular interactions, producing up to around 10% expansion or contraction of the whole crystal, [4] thus making them of interest as actuators [5][6][7] but also in electronic devices [8][9][10] or in nanothermometry. [11] The ultrafast spin state switching deserves investigations on the impact of the mechanical changes at the nanoscale especially in opto-electronic [12,13] or memristance [14][15][16] devices involving SCO. Indeed, this volume change is likely to create internal strains and therefore alter the SCO through structural fatigability, [17][18][19] even if mechanical resilience [20] has been evidenced.…”

“…[26][27][28][29][30][31][32][33][34][35] This can be applied to generate room temperature opto-electronic devices. [13] The efficiency and speed of such photothermal effect can be highly improved by reducing the size of the particles [32,36] and incorporating nanoheaters into the SCO particles, like gold nanoparticles that produce heat when excited in their surface plasmon resonance (SPR) band. [37] Indeed, the absorption coefficient of plasmonic nanoparticles is much higher than of the SCO compound.…”

Dynamics of Spin Crossover Molecular Complexes

“…The main experimental bottleneck to the study of voltage driven spin state switching is the low-conductivity (even insulating) and high impedance of most SCO complexes and hence of the related molecular devices [ 8 ]. Indirect measurements using graphene electrical detectors, shown for LIESST [ 132 ] and thermal transition [ 133 ] of SCO thin films or nanoparticles, can possibly take advantage of the RF graphene electronics circuit. These hybrid devices open the door to probing electronic properties of SCO devices down the ns time range, as well as making possible high-frequency operation of such switching organic devices.…”

Inverse spin crossover in fluorinated Fe(1,10-phenanthroline)$_2$(NCS)$_2$ adsorbed on Cu (001) surface

“…5 However, recently the principle of electrical detection of the light-induced spin transition in SCO/graphene heterostructures was demonstrated 6 and even room temperature optoelectronic device operating with spin crossover nanoparticles. 7 The SCO molecules are composed essentially of a transition element ion complex, like iron (II), surrounded by ligands. When the ligands take an octahedral or tetrahedral conformation around the metallic element, they generate a field called "ligand field ∆" operating on the d orbitals of the metallic ion.…”