Role of the Anion on the Transport and Structure of Organic Mixed Conductors
Giovannitti , Alexander
KAUST DepartmentBiological and Environmental Sciences and Engineering (BESE) Division
Chemical Science Program
KAUST Solar Center (KSC)
Physical Science and Engineering (PSE) Division
Online Publication Date2018-12-19
Print Publication Date2019-02
Permanent link to this recordhttp://hdl.handle.net/10754/631224
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AbstractOrganic mixed conductors are increasingly employed in electrochemical devices operating in aqueous solutions that leverage simultaneous transport of ions and electrons. Indeed, their mode of operation relies on changing their doping (oxidation) state by the migration of ions to compensate for electronic charges. Nevertheless, the structural and morphological changes that organic mixed conductors experience when ions and water penetrate the material are not fully understood. Through a combination of electrochemical, gravimetric, and structural characterization, the effects of water and anions with a hydrophilic conjugated polymer are elucidated. Using a series of sodium-ion aqueous salts of varying anion size, hydration shells, and acidity, the links between the nature of the anion and the transport and structural properties of the polymer are systematically studied. Upon doping, ions intercalate in the crystallites, permanently modifying the lattice spacings, and residual water swells the film. The polymer, however, maintains electrochemical reversibility. The performance of electrochemical transistors reveals that doping with larger, less hydrated, anions increases their transconductance but decreases switching speed. This study highlights the complexity of electrolyte-mixed conductor interactions and advances materials design, emphasizing the coupled role of polymer and electrolyte (solvent and ion) in device performance.
CitationCendra C, Giovannitti A, Savva A, Venkatraman V, McCulloch I, et al. (2018) Role of the Anion on the Transport and Structure of Organic Mixed Conductors. Advanced Functional Materials 29: 1807034. Available: http://dx.doi.org/10.1002/adfm.201807034.
SponsorsThe authors acknowledge support from the National Science Foundation including Grant No. NSF DMR-1751308 (J.R.), Grant No. NSF DMR-1507826 (A.S.), and Grant No. NSF DMR-1808401 (C.C.). C.C. also gratefully acknowledges support from the “la Caixa” Foundation. Portions of this research were carried out at the Stanford Synchrotron Radiation Lightsource, a national user facility operated by Stanford University on behalf of the U.S. Department of Energy, Office of Basic Energy Sciences. A.G. and I.M. acknowledge funding from Engineering and Physical Sciences Research Council Project EP/G037515/1 and EP/N509486/1. This work utilized the Northwestern University Micro/Nano Fabrication Facility (NUFAB), which is partially supported by the Soft and Hybrid Nanotechnology Experimental (SHyNE) Resource (Grant No. NSF ECCS-1542205), the Materials Research Science and Engineering Center (Grant No. NSF DMR-1720139), the State of Illinois, and Northwestern University.
JournalAdvanced Functional Materials