Morphology of PEDOT-PSS

The structure and morphology of thin films might be different than those of bulk material. For PEDOT, thin spin-cast and bulk solution- 

---

D., 2007. Influence of ionic liquids on the electrical conductivity and morphology of PEDOT PSS films. Chem. mater. 19,2147-2149. 

Different models exist to describe the morphology of PEDOT PSS films. A lamellae model was proposed by lonescu-Zanetti et al. With conductivity... 

M. Dobbelin, R. Marcilla, M. Salsamendi, C. Pozo-Gonzalo, P. M. Carrasco, J. A. Pomposo, and D. Mecerreyes. 2007. Influence of ionic liquids on the electrical conductivity and morphology of PEDOT PSS films. Chem Mater 19(9) 2147-2149. 

Morphological studies were performed by SEM observations of PEDOT-PSS/PVAc composites of electrospun nanofibers and the samples for the SEM measurements are coated with gold. 

The thickness of the gold coating was about 30 nm. Diameters of nanofibers were calculated using image J software. SEM images show that morphology of the nanofiber mats of PEDOT-PSS/PVAc composites changed with different amounts of PEDOT-PSS. SEM pictures of electrospun nanofibers are presented in Fig. 5.15a-g. 

Significant changes in fiber diameter and morphology with different PEDOT-PSS contents was realized. By using different solvents and mixtures different fiber diameters have been observed. Figure 5.16 shows the relationship between PEDOT-PSS content and diameter of nanofibers where increasing the amount of PEDOT-PSS caused an increase in fiber diameter. 

Products were characterized by Fourier transform infrared spectrophotometry-attenuated total reflectance (FTIR-ATR), ultraviolet visible (UV-Vis) spectrophotometry, scanning electron microscopy (SEM), and broadband dielectric/impedance spectroscopy (BDS). New absorption bands were observed corresponding to the conjugated pol5mieric units by FTIR-ATR and UV-Vis spectrophotometric analysis. The influence of concentration of PEDOT-PSS and PEDOT on the composite electrospun nanofibers was studied by EIS. Morphologies of electrospun nanofibers were also investigated by SEM. 

In this section, several PES studies on selected properties of PEDOT-PSS that are relevant to certain applications in organic electronics are reviewed. The unique initial-state binding energies of the sulfur atoms in the PEDOT and the PSS portions of the polymer blend make it possible to distinguish PEDOT from PSS within PEDOT-PSS films. We focus on the analysis of the elemental composition, the PEDOT-to-PSS ratio, some aspects of the granular morphology, and some additional chemical information (for example, an estimate of the doping level). 

S. Timpanaro, M. Kemerink, F. J. Touwslager, M. M. De Kok and S. Schrader, Morphology and conductivity of PEDOT/PSS films studied by scanning-tunneling microscopy, Chem. Phys. Lett. 394(4-6), 339-343 (2004). H. Okuzaki, PEDOT/PSS patterning for plastic electronics, Kobunshi Kako 54(8), 361-312 (2005). 

A. M. Nardes, R. A. J. Janssen, and M. Kemerink. 2008. A morphological model for the solvent-enhanced conductivity of PEDOT PSS thin films. Adv Fund Mater 18(6) 865-871. 

Carter and coworkers studied how side-chain branching in PFs affects device performance with and without an additional HTL of cross-linkable polymer 2 [ 19]. They found that the device efficiency is affected more by the position of the exciton recombination zone than by variations of polymer morphology induced by side-chain branching, which mainly controls the relative emission between vibrational energy levels and has a minimal effect on polymer charge transport properties. For double-layer devices (ITO/PEDOT PSS/2/3,4, or 5/Ca), a typical brightness of 100 cdm 2 at 0.8 MV cm-1, maximum luminance of 10 000 cd m-2 at 1.5 MV cm x, and device efficiencies between 1.3 and 1.8 cd A 1 for 3 and 5 branching can be achieved. 

Composite conductive fibers based on poly(3,4-ethylene-diox)d hiophene]-polystyrene sulfonic acid (PEDOT-PSS) solution blended with polyacrylonitrile (PAN] were obtained via wet spinning. The influence of draw ratio on the morphology, structure, thermal degradation, electrical conductivity, and mechanical properties of the resulting fibers was investigated. The results revealed that the PEDOT-PSS/PAN composite conductive fibers crystallization, electrical conductivity and mechanical properties were improved with the increase of draw ratio. The thermal stability of the fibers was almost independent of draw ratio, and only decreased slightty with draw ratio. Besides, when the draw ratio was 6, the conductivity of the PEDOT-PSS/PAN fibers was 5.0 S cm, ten times the conductivity when the draw ratio was 2 (Fig 5.10]. ... 

Snaith, H.J., H. Kenrick, M. Chiesa, and R.H. Friend. 2005. Morphological and electronic consequences of modifications to the polymer anode PEDOT PSS. Polymer 46 2573-2578. 

Surface morphology of films was measured by the optical interferogram (Wyko) of 60 p,m x 45.5 p,m area. For comparison, formulated ink was spin-coated on a glass substrate with the same thickness of 220 mn, which is similar to that of an inkjet-printed layer. No pin-holes were observed on layers deposited using either techniques. However, in both cases, many randomly positioned voids have been observed on the dried PEDOT-PSS surface. Figure 3.9a shows the surface of the inkjet-printed film... 

---