Morphology of Nanometer-Sized PEDOT:PSS Nanoparticles

Solution-processed conducting polymer complex of poly(3,4-ethylenedioxythiophene):poly (styrene sulfonate) (PEDOT:PSS) has been widely used in the fields of organic electronics and optoelectronics due to its outstanding electronic properties and processing superiority. It is important to understand the nanostructure of PEDOT:PSS to manipulate its electronic properties. In this work, it is reported that PEDOT:PSS nanoparticles with an average size of ≈22 nm are observed via scanning electron microscopy (SEM) by diluting the dispersion and by alcohol treatment. Specifically, the traditional dispersion (1.0-1.3 wt.%) is diluted one million times and then treated with ultrasonication and polar alcohols. The treatments of ultrasonication and polar alcohols help to reduce the entanglement of PEDOT:PSS chains and remove excess PSS, which leads to the exposure of the nanometer-sized PEDOT:PSS particles. Moreover, quantum-sized PEDOT:PSS dots with a size range of 2-3 nm are observed by transmission electron microscopy (TEM).