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Nikita Konstantinov

Bio: Nikita Konstantinov is an academic researcher from University of Strasbourg. The author has contributed to research in topics: Graphene & Spin crossover. The author has an hindex of 2, co-authored 3 publications receiving 19 citations.

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Journal ArticleDOI
TL;DR: In this article, a hybrid device constructed from a spin crossover (SCO) thin film of a Fe[HB(3,5-(Me)2Pz)3]2 molecular material evaporated over a graphene sensing layer is demonstrated.
Abstract: Magneto-opto-electronic properties are shown for a hybrid device constructed from a spin crossover (SCO) thin film of a Fe[HB(3,5-(Me)2Pz)3]2 molecular material evaporated over a graphene sensing layer. The principle of electrical detection of the light-induced spin transition in SCO/graphene heterostructures is demonstrated. The switchable spin state of the molecular film is translated into a change of conductance of the graphene channel. The low temperature write/erase process of the conductive remnant states is implemented using two distinct excitation wavelengths, in the red (light-induced spin state trapping, LIESST) region for stabilizing the metastable paramagnetic state, and in the near infrared (reverse-LIESST) region for retrieving the stable diamagnetic state. The bistability of the system is confirmed over a significant temperature window through light-induced thermal hysteresis (LITH). This opens new avenues to study the light-induced spin transition mechanisms exploring the coupling mechanisms between SCO systems and 2D materials, providing electrical readings of the molecules/2D substrate interfaces. These results demonstrate how the electronic states of insulating molecular switches can be stored, read and manipulated by multiple stimuli, while transducing them into low impedance signals, thanks to two-dimensional detectors, revealing the full potential of mixed-dimensional heterostructures for molecular electronics and spintronics.

33 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show how a graphene underlayer reveals the light-induced heating that triggers a spin transition, paving the way for using these molecules for room temperature optoelectronic applications.
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 elusive, as optical changes between metastable spin states require cryogenic temperatures. Furthermore, electrical detection is hampered by the intrinsic low conductivity properties of these materials. We show here how a graphene underlayer reveals the light-induced heating that triggers a spin transition, paving the way for using these molecules for room temperature optoelectronic applications.

17 citations


Cited by
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Journal Article
TL;DR: It is demonstrated that a combination of scanning tunnelling microscopy measurements and ab initio calculations allows discriminating unambiguously between both states by local vibrational spectroscopy, which opens a way to molecular scale control of two-dimensional spin cross-over layers.
Abstract: Spin cross-over molecules show the unique ability to switch between two spin states when submitted to external stimuli such as temperature, light or voltage. If controlled at the molecular scale, such switches would be of great interest for the development of genuine molecular devices in spintronics, sensing and for nanomechanics. Unfortunately, up to now, little is known on the behaviour of spin cross-over molecules organized in two dimensions and their ability to show cooperative transformation. Here we demonstrate that a combination of scanning tunnelling microscopy measurements and ab initio calculations allows discriminating unambiguously between both states by local vibrational spectroscopy. We also show that a single layer of spin cross-over molecules in contact with a metallic surface displays light-induced collective processes between two ordered mixed spin-state phases with two distinct timescale dynamics. These results open a way to molecular scale control of two-dimensional spin cross-over layers.

82 citations

Journal ArticleDOI
TL;DR: In this paper, spin crossover nanoparticles were covalently grafted onto functionalized layers of semiconducting MoS2 to form a hybrid heterostructure and the spin crossover caused a substantial and reversible change of the electrical and optical properties of the heterostructures.
Abstract: In the past few years, the effect of strain on the optical and electronic properties of MoS2 layers has attracted particular attention as it can improve the performance of optoelectronic and spintronic devices. Although several approaches have been explored, strain is typically externally applied on the two-dimensional material. In this work, we describe the preparation of a reversible ‘self-strainable’ system in which the strain is generated at the molecular level by one component of a MoS2-based composite material. Spin-crossover nanoparticles were covalently grafted onto functionalized layers of semiconducting MoS2 to form a hybrid heterostructure. Their ability to switch between two spin states on applying an external stimulus (light irradiation or temperature change) serves to generate strain over the MoS2 layer. A volume change accompanies this spin crossover, and the created strain induces a substantial and reversible change of the electrical and optical properties of the heterostructure. Spin-crossover nanoparticles have been covalently grafted onto a semiconducting MoS2 layer to form a self-strainable heterostructure. Under light or thermal stimulus, the nanoparticles switch between their high- and low-spin states, in which they have different volumes. This generates a reversible strain over the MoS2 layer and, in turn, alters the electrical and optical properties of the heterostructure.

38 citations

Journal ArticleDOI
TL;DR: In this paper, the authors introduce emerging 2DMs, various classes of macro-molecules, and molecular switches and discuss their relevant properties, and discuss the use of molecules and assemblies thereof to boost the performance of 2D transistors for CMOS applications and to impart diverse functionalities in beyond-CMOS devices.
Abstract: Two-dimensional materials (2DMs) have attracted tremendous research interest over the last two decades. Their unique optical, electronic, thermal, and mechanical properties make 2DMs key building blocks for the fabrication of novel complementary metal-oxide-semiconductor (CMOS) and beyond-CMOS devices. Major advances in device functionality and performance have been made by the covalent or noncovalent functionalization of 2DMs with molecules: while the molecular coating of metal electrodes and dielectrics allows for more efficient charge injection and transport through the 2DMs, the combination of dynamic molecular systems, capable to respond to external stimuli, with 2DMs makes it possible to generate hybrid systems possessing new properties by realizing stimuli-responsive functional devices and thereby enabling functional diversification in More-than-Moore technologies. In this review, we first introduce emerging 2DMs, various classes of (macro)molecules, and molecular switches and discuss their relevant properties. We then turn to 2DM/molecule hybrid systems and the various physical and chemical strategies used to synthesize them. Next, we discuss the use of molecules and assemblies thereof to boost the performance of 2D transistors for CMOS applications and to impart diverse functionalities in beyond-CMOS devices. Finally, we present the challenges, opportunities, and long-term perspectives in this technologically promising field.

25 citations

Journal ArticleDOI
TL;DR: In this article, the authors discuss the progress and challenges facing the fabrication of molecular multiferroic devices, which could be considered competitive to silicon, and discuss the potential for low-cost molecular solid-state memory because the essential molecular thin films are easily fabricated.
Abstract: Nonvolatile, molecular multiferroic devices have now been demonstrated, but it is worth giving some consideration to the issue of whether such devices could be a competitive alternative for solid-state nonvolatile memory. For the Fe (II) spin crossover complex [Fe{H2B(pz)2}2(bipy)], where pz = tris(pyrazol-1-yl)-borohydride and bipy = 2,2′-bipyridine, voltage-controlled isothermal changes in the electronic structure and spin state have been demonstrated and are accompanied by changes in conductance. Higher conductance is seen with [Fe{H2B(pz)2}2(bipy)] in the high spin state, while lower conductance occurs for the low spin state. Plausibly, there is the potential here for low-cost molecular solid-state memory because the essential molecular thin films are easily fabricated. However, successful device fabrication does not mean a device that has a practical value. Here, we discuss the progress and challenges yet facing the fabrication of molecular multiferroic devices, which could be considered competitive to silicon.

19 citations

Journal ArticleDOI
TL;DR: In this paper, the authors show how a graphene underlayer reveals the light-induced heating that triggers a spin transition, paving the way for using these molecules for room temperature optoelectronic applications.
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 elusive, as optical changes between metastable spin states require cryogenic temperatures. Furthermore, electrical detection is hampered by the intrinsic low conductivity properties of these materials. We show here how a graphene underlayer reveals the light-induced heating that triggers a spin transition, paving the way for using these molecules for room temperature optoelectronic applications.

17 citations