Sergi Riera-Galindo1,Raphael Pfattner1,2,Elena Laukhina2,Marta Mas-Torrent1,2,Vladimir Laukhin1,Jaume Veciana1,2
Materials Science Institute of Barcelona (ICMAB-CSIC)1,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN)2
Sergi Riera-Galindo1,Raphael Pfattner1,2,Elena Laukhina2,Marta Mas-Torrent1,2,Vladimir Laukhin1,Jaume Veciana1,2
Materials Science Institute of Barcelona (ICMAB-CSIC)1,Networking Research Center on Bioengineering, Biomaterials and Nanomedicine (CIBER-BBN)2
Developing smart materials that can respond to an external stimulus is of major interest in artificial sensing devices able to read information about the physical, chemical and/or biological changes produced in our environment. Additionally, if these materials can be deposited or integrated on flexible, transparent substrates, their appeal is greatly increased. The BEDT-TTF=bis(ethylenedithio)-tetrathiafulvalene based quasi-twodimensional organic superconductor β-(BEDT-TTF)<sub>2</sub>I<sub>3</sub> was first reported back in 1984.<sup>[1]</sup> Soon it became clear that ion radical salts derived from BEDT-TTF exhibit tunable electronic band structures. Therefore, such molecules are excellent building blocks for engineering a rich and diverse family of organic crystalline metals and semiconductors. When processed in composites, the high electrical performance of single crystals can be combined with the processing properties of polymers where at the percolation threshold, fascinating novel optoelectronic properties emerge.<sup>[</sup><sup>2</sup><sup>] </sup>Such systems can be further tuned by choosing the nature of the conductor enabling high sensitivity towards strain, pressure, temperature, humidity or even con-tactless radiation sensing <i>i.e.</i> bolometers.<sup>[</sup><sup>3-5</sup><sup>] </sup>This rich class of materials ranges from metals to semi-metals and semiconductors and is highly sensitive to a variety of external stimuli. Mechanisms of responses are discussed and correlated with fundamental properties of charge transport in these systems. Such materials allow for selective sensing enabled due to molecular design and structural control of the active components. These findings are highly promising for multidimensional selective sensing made possible by tuning molecular composition to maximize and, importantly, to decouple responses to strain, pressure, temperature, radiation, and recently also humidity as an external stimulus. An attractive field of application in this context is human health care targeting environmental conditions relevant for human physiology.<br/><br/>References:<br/>E. B. Yagubskii, I. F. Shchegolev, V. N. Laukhin, et.al., JETP Lett., (1984), 39, 12.<br/>R. Pfattner, E. Laukhina, J. Li, et.al, ACS Appl. Electron. Mater. (2022), 4, 2432.<br/>E. Laukhina, R. Pfattner, L. R. Ferreras, et. al., Adv. Mater., (2009), 21, 1-5.<br/>R. Pfattner, V. Lebedev, E. Laukhina, et.al., Adv. Electr. Mater., (2015), 1, 1500090.<br/>R. Pfattner, E. Laukhina, L. Ferlauto, et.al, ACS Appl. Electr. Mater., (2019), 1, 1781.