A Free‐Standing Molecular Spin–Charge Converter for Ubiquitous Magnetic‐Energy Harvesting and Sensing

Abstract

Magnetic-energy harvesting in a centimeter-sized free-standing (BEDT-TTF)C charge-transfer single crystal is demonstrated. The crystal shows sensitive magnetic-, thermal-, and mechanical-sensing ability, with an excellent piezoresistance coefficient of -5.1 × 10 Pa . The self-powered sensing performance, together with its solution processability and flexibility, endow it with the capability of driving a new generation of noncontact magnetic-energy harvesting and sensing technologies.

Organic Donor‐Acceptor Cocrystals for Multiferroic Applications

“…[19][20] The Ren group has done lots of explorations on the C 60 -based organic CT multiferroics. [29][30][31][32][33][34]77,82] A segregated-stack cocrystal with a long-range ordered CT network based on the electron donor TTF and acceptor C 60 was observed to display an unusual multitude of external stimulicontrolled ferroic properties, due to the modulation of chargespin composite orders (Figure 3a, b). [34] The density of singlet and triplet CT can be tuned by the magnetic field owing to the formation rate of spin-parallel and spin-antiparallel states for the competition of spin-conserving and spin-mixing.…”

“…Remarkably, by virtue of the advantages in simultaneously performing the magneticenergy harvesting and multi-external-stimuli sensing functionalities, as well as the materials-by-design freedom, the organic CT multiferroic cocrystal of (BEDT-TTF) 2 C 60 (BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene) was proved to be applied as a spin-charge converter that could convert spin information to electrical energy. [33] Another typical C 60 -based CT multiferroics system is the family of thiophene-based compounds, where thiophene acts as the electron-donating moiety. [29][30]32,72,77] For instance, by co- assembling thiophene donor and C acceptor together into athree-dimensional CTC with a hierarchical organization and long-range noncovalent interactions (segregated-stack), a remarkable anisotropic magnetization and room temperature multiferroicity can be achieved.…”

“…However, some innovative and breakthrough researches have been obtained and significantly boosted the development of this field. [25,[27][28][29][30][31][32][33][34][35][36][37] Although many other systems such as polymers, [38a,b] covalent organic frameworks (COFs), [38c] or metal-organic frameworks (MOFs) [38d-f] have been demonstrated to show multiferroics properties, we only discuss recent progress in organic donor-acceptor cocrystals for multiferroic applications in this minireview. We begin with a brief description of multiferroics including the definition, history, evolution, significance, category and fundamental research to build a basic knowledge framework on the field, and then proceed with the presentation of the progress in experimental and theoretical investigations on organic CT multiferroics in the past decade.…”

The First Molecule‐Based Blue‐Light Optical‐Dielectric Switching Material in Both Hybrid Bulk Crystal and Flexible Thin Film Forms

“…Therefore, blue‐light molecule‐based optical‐dielectric material possesses the mark of its real genius as an ultraflexible device. Molecular material has become one of the hotspots of current research in thin‐film field‐effect transistors, electroluminescent devices, switches, memories, and solar cells . For example, photovoltaic material (CH 3 NH 3 PbI 3 ) and lead‐based bluish white light‐emitting perovskite (C 4 N 2 H 14 PbBr 4 ) have shown great promises used in field‐effect transistors, light‐emitting diodes, and photodetectors .…”

Optically Controlled Magnetization and Magnetoelectric Effect in Organic Multiferroic Heterojunction

“…Additionally, magnetism is found in organic tetrakis(dimethylamino)ethylene‐fullerene charge transfer system due to the fullerene merohedral disorder induced spin ordering . Furthermore, organic multiferroic effects are realized in TTF‐BA (tetrathiafulvalene‐ p ‐bromanil) ( T c = 52 K), κ‐(BEDT‐TTF) 2 Cu[N(CN) 2 ]Cl ( T c = 26 K), and polythiophene (polythiophene nanowire) based charge transfer crystals, where the long‐range ferroelectric and magnetic orders are caused by the localized charge and spin ordering, respectively. It should be noted that organic charge transfer complex does not have 3d electrons.…”