Materials exhibiting a spontaneous electrical polarization1,2 that can be switched easily between antiparallel orientations are of potential value for sensors, photonics and energy-efficient memories. In this context, organic ferroelectrics3,4 are of particular interest because they promise to be lightweight, inexpensive and easily processed into devices. A recently identified family of organic ferroelectric structures is based on intermolecular charge transfer, where donor and acceptor molecules co-crystallize in an alternating fashion known as a mixed stack5,6,7,8: in the crystalline lattice, a collective transfer of electrons from donor to acceptor molecules results in the formation of dipoles that can be realigned by an external field as molecules switch partners in the mixed stack. Although mixed stacks have been investigated extensively, only three systems are known9,10 to show ferroelectric switching, all below 71 kelvin. Here we describe supramolecular charge-transfer networks that undergo ferroelectric polarization switching with a ferroelectric Curie temperature above room temperature. These polar and switchable systems utilize a structural synergy between a hydrogen-bonded network and charge-transfer complexation of donor and acceptor molecules in a mixed stack. This supramolecular motif could help guide the development of other functional organic systems that can switch polarization under the influence of electric fields at ambient temperatures.
Access optionsAccess options
Subscribe to Journal
Get full journal access for 1 year
only $3.90 per issue
All prices are NET prices.
VAT will be added later in the checkout.
Rent or Buy article
Get time limited or full article access on ReadCube.
All prices are NET prices.
This work was supported by the Non-equilibrium Energy Research Center (NERC) at Northwestern University, funded by the US Department of Energy (DOE), Office of Basic Energy Sciences under award number DE-SC0000989. A.K.S. received support from the Materials Research Science and Engineering Centre (MRSEC) at Northwestern University, funded by the National Science Foundation (NSF). D.C., A.C.F. and J.F.S. were supported by the WCU program (R-31-2008-000-10055-0) at KAIST in Korea. Use of the Center for Nanoscale Materials was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract no. DE-AC02-06CH11357. D.C. and A.C.F. were supported by NSF Graduate Research Fellowships. A.K.S. and A.C.-H.S. were supported by a fellowship from the NERC. A.S.T. was supported by a fellowship from the Initiative for Sustainability and Energy at Northwestern (ISEN) and NERC. We thank J. B. Ketterson and O. Chernyashevskyy (Northwestern University) for discussions and advice, Y. D. Shah (Northwestern University) for assistance with ferroelectricity measurements, A. M. Z. Slawin (University of St Andrews) for initial help with crystallographic data collection and refinement, M. Mara (Northwestern University) for assistance with spectroscopy, Y. Liu (The Molecular Foundry, Lawrence Berkeley National Laboratory) for discussions, and the Integrated Molecular Structure Education and Research Centre (IMSERC) and the Magnet and Low Temperature Facility at Northwestern University for providing access to equipment for the relevant experiments. Molecular crystal images were produced using the UCSF Chimera package from the Resource for Biocomputing, Visualisation and Informatics at the University of California, San Francisco.
This zipped file contains 3 data files. Crystallographic Information File 1 is the Crystallographic Information File (CIF) for the supramolecular network 1·2. Crystallographic Information File 2 is the Crystallographic Information File (CIF) for the supramolecular network 1·3 and Crystallographic Information File 3 is the Crystallographic Information File (CIF) for the supramolecular network 1·4.
About this article
Recognition Properties and Self‐assembly of Planar [M(2‐pyridyl‐1,2,3‐triazole) 2 ] 2+ Metallo‐ligands
Chemistry – An Asian Journal (2019)