Keywords :
Bond-breaking; Crucial parameters; Decouplings; DFT method; Diarylethenes; Light activated switches; Molecular junction; Molecular switches; Performance; Trade off; Electronic, Optical and Magnetic Materials; Energy (all); Physical and Theoretical Chemistry; Surfaces, Coatings and Films; General Energy
Abstract :
[en] Diarylethene molecules are regularly used in molecular junctions as light-activated switches. Two crucial parameters drive the performance of these switches: (i) ON-OFF ratios and (ii) reversibility. In this work, we first show using the theoretical NEGF-DFT method that an efficient decoupling between the molecular backbone and the electrodes, which is necessary for reversibility, unfortunately, tends to weaken the ON-OFF ratio. We then show that this trade-off situation can be avoided by considering an alternative "transverse" contact configuration of the diarylethene, which exploits the bond breaking associated with the isomerization reaction. Interestingly, this transverse contact ensures both high on-off ratios (at least by 2 orders of magnitude) and an efficient decoupling of the active unit from the gold electrodes.
Funding text :
C.V.D. gratefully acknowledges the computational support obtained from the Center for Nanoscale Materials (CNM at Argonne National Lab), an Office of Science User Facility, supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under Contract No. DE-AC02-06CH11357. The work of I.A. is supported by the Belgian National Fund for Scientific Research (F.R.S.-FNRS), thanks to the project SPINFUN (Convention T.0054.20). The authors also acknowledge the Consortium des Équipements de Calcul Intensif (CéCI) funded by the Belgian National Fund for Scientific Research (F.R.S.-FNRS) for providing the computational resources. J.C. is an FNRS research director.
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