Electrical conductivity Charge-transfer complex

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edge-on view of portion of crystal structure of hexamethylenettf/tcnq charge transfer salt, highlighting segregated stacking.



end-on view of portion of crystal structure of hexamethylenettf/tcnq charge transfer salt. distance between ttf planes 3.55 Å.


in 1954, charge-transfer salt reported resistivities low 8 ohm·cm in combinations of perylene iodine or bromine. in 1962, well-known acceptor tetracyanoquinodimethane (tcnq) reported. tetrathiafulvalene (ttf) synthesized in 1970 , found strong electron donor. in 1973, discovered combination of these components form strong charge-transfer complex, henceforth referred ttf-tcnq. complex formed in solution , may crystallized well-formed crystalline solid. solid shows metallic electrical conductance , first discovered purely organic conductor. in ttf-tcnq crystal, ttf , tcnq molecules arranged independently in separate parallel-aligned stacks, , electron transfer occurs donor (ttf) acceptor (tcnq) stacks. hence, electrons , electron holes separated , concentrated in stacks , can traverse in one-dimensional direction along tcnq , ttf columns, respectively, when electric potential applied ends of crystal in stack direction.


superconductivity exhibited tetramethyl-tetraselenafulvalene-hexafluorophosphate (tmtsf2pf6), semi-conductor @ ambient conditions, shows superconductivity @ low temperature (critical temperature) , high pressure: 0.9 k , 12 kbar. unfortunately, critical current densities in these complexes small.








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