Charge-transfer complexes of sulfur-rich acceptors derived from birhodanines

Abstract : Sulfur-rich acceptors, birhodanines, 3,3'-dialkyl-5,5'-bithiazolidinylidene-2,2'-dione-4,4'-dithiones (OS-R, R = Et and Pr) and 3,3'-dialkyl-5,5'-bithiazolidinylidene-4,4'-dione-2,2'-dithiones (SO-R, R = Et), as well as the sulfur analogues, 3,3'-dialkyl-5,5'-bithiazolidinylidene-2,4,2', 4'-tetrathiones (SS-R, R = Et, Pr), form 1 1 composition charge-transfer complexes with donors such as pyrene, perylene, and coronene. These complexes have mixed stacks, and the SS-R complexes show n-channel transistor properties due to the intercolumnar S center dot center dot center dot S contacts between the acceptors. By contrast, the OS-R and SO-R complexes exhibit basically hole-dominant ambipolar properties due to the absence of S center dot center dot center dot S contacts. Accordingly, the charge transport is governed mostly by the direct interchain interactions instead of the transport along the columns.