Coulomb blockade transport emerged in quasi one-dimensional PEDOT: PSS fiber

In organic materials, peculiar nonlinearity to current voltage appears, thought a general and comprehensive explanation of them is still controversial. Conductive segments in poorly conductive organic materials are expected to have a smaller electrical capacity, leading to a higher critical temperature for the blockade effect. Here we show an experimental evidence of Coulomb blockade taking place on quasi one-dimensional conductive polymer, PEDOT:PSS [poly (3, 4-ethylenedioxy-thiophene) doped with poly (styrene sulfonate) anions], fibers. The PEDOT:PSS wire grows through electro-polymerization, and bridges between electrodes immersed in EDOT monomer solution. Conducting measurement for the dried fibers shows clear nonlinear behaviour in the current-voltage characteristics as temperature decreases. The non-zero threshold voltage, which increased with decreasing temperature, appears in the current flows through a thinnest fiber. The effective percolative transport passes in thin fiber is able to consists of the connection of the Coulomb blockade islands. By considering both the charge blockade effect and the influence of structural disorder and dimensionality, it is hoped that a clear understanding of charge transport in organic materials can be achieved.