Flexible and Optically Transparent Polymer Embedded Nano/Micro Scale Spin Crossover Fe(II) Complex Patterns/Arrays

Abstract

A novel highly soluble spin-crossover (SCO) [FeII( L )2](BF4)2 complex ( I ) was prepared, where L = 4,4″-dioctylated 2′,6′-bispyrazolylpyrine. Complex I shows reversible temperature dependent SCO behavior with a T 1/2 centered around 270 K. Exploiting the high solubility and hence superior processability of complex I nano/micro scale arrays and square patterns were fabricated on a glass substrate. Additionally, for the first time, for the possible flexible technological applications, the SCO arrays (area: 2 mm2) were successfully embedded within an optically transparent thin polystyrene film and studied using Raman spectroscopy/imaging technique. Variable temperature Raman spectroscopy studies further confirmed the SCO behavior of complex I .

Spatio-temporal Investigations of the Incomplete Spin Transition in a Single Crystal of [Fe(2-pytrz)2{Pt(CN)4}]·3H2O: Experiment and Theory

“…where, we have kept the general expression of f ( r), given in Equation (5). Considering that the order parameter varies with the local velocity, as n HS ( r, t) = n HS ( r, t 0 ) +ṅ HS × t, we can estimate the rate of variation of F at t 0 , as follows…”

“…Multi-functional molecular materials with intrinsic physical properties at the molecular scale constitute serious candidates for their use as nano-memories, nano-switches or nano-probes due to many advantages, like their easy processability and their low cost. In this context, spin crossover (SCO) materials, based on iron (II) complexes, have been recognized as prime candidates, in particular due to their variety of nano-structuration possibilities [1][2][3][4][5] allowing their integration into devices for a various set of currently considered applications, e.g., as display and memory devices [6][7][8][9] , sensing of temperature [10][11][12], probes of contact pressure or shocks [13], as well as actuators [14][15][16]. From the thermodynamic point of view, the SCO phenomenon is an entropic-driven mechanism involving the switching between two different electronic states, namely a diamagnetic low-spin (LS) state and a paramagnetic high-spin (HS) state, as a response to the application of an external stimulus.…”

Evidence of Photo-Thermal Effects on the First-Order Thermo-Induced Spin Transition of [{Fe(NCSe)(py)2}2(m-bpypz)] Spin-Crossover Material

“…These materials [3][4][5] are recognized for their serious applications thanks to their reversible switching properties using temperature, pressure variations [6,7], light [8][9][10][11][12][13][14][15][16], magnetic [17,18] and electric [19][20][21] fields, etc. It is important to notice that iron(II)-based spin-crossover (SCO) materials have been recognized as well adapted candidates for nano-structuration potentialities [22][23][24][25][26], allowing their integration into devices for various applications, such as display and memory devices [27][28][29][30], multimodal sensing [31][32][33], probes of contact pressure or shocks [7], as well as actuators [34][35][36].…”

Solvent-triggered relaxative spin state switching of [Fe(HB(pz)3)2] in a closed nano-confinement of NH2-MIL-101(Al)

“…31 , 32 Production of functional, individually 5 addressable, SCO units 3,33 as small as possible is an important problem actively researched in the area of SCO nanomaterials. 34 , 35 Various methods for the synthesis of SCO nanoparticles 36,37,38 and thin films 39,40 including nanopatterned 41 growth were successfully implemented, also as prototypical 10 functional elements for nanodevices. 42 One of the traditional problems in nanostructuration refer to the loss of abruptness in thermal-and pressure-induced SCO, which is associated with reduction of cooperative effects, i.e., the reduced efficiency of elastic interactions in the solid-state, propagating the effect of 15 structural changes during the spin transition.…”