PEDOT/PSS electrodes

Typical of polymer conductors, these PEDOT-PSS electrodes exhibit an electrical conductivity of around 0.1 S/cm [11], A uniform, continuous pentacene (p-type organic semiconductor) layer is then deposited on the PEDOT-PSS source and drain electrodes to complete the bottom-contact OTFTs. Since pentacene is deposited in the final step, it is not exposed to any of the solvents (e.g., acetone) required to prepattem the PEDOT-PSS electrodes. These bottom-contact pentacene TFTs with PEDOT-PSS electrodes exhibit charge-carrier mobilities comparable to charge-carrier mobilities of typical bottom-contact pentacene TFTs with gold electrodes (0.2 cmWs) [1] and on/off current ratios as high as 10 . Eurther, these device characteristics are on par with requirements for driving most display applications [12,13]. 

In addition to lower process costs, an additional technical advantage of the use of a PEDOT PSS-based printing paste for the transparent conductor is the flexibility of the contact layer. ITO is a brittle material not ideally suited to destruction-free thermal deformation. In contrast, devices fabricated with transparent, conductive PEDOT PSS electrodes can be three-dimensionally [119] thermoformed after construction of the EL elements. 

P3HT and [60]PCBM through the thickness of the photoactive layer. It has proved, in particular, that concentration of P3HT is higher at the ITO/PEDOT PSS electrode for the annealed blend films (Figure 53). 

FIG. 3.35. Experimental J—V characteristics of an ITO/PEDOT PSS/PCBM/Au injection limited electron current (triangles) and calculated space charge limited hole current in OC4C10-PPV (circles) for a thickness of L = 170 nm and temperature T = 290 K. The inserted figure represents die device band diagram under the flat band condition of a bulk heterojunction solar cell using Au as a top electrode [65]. 

Other conducting polymers can be investigated as supports for dispersing catalytic metallic particles. Shan and Pickup [21] used a composite of poly(3,4-ethylenedioxythiophene) and poly(styrene-4-sulfonate) (PEDOT/PSS) to disperse Pt particles. They compared the performances of such electrodes with carbon-supported Pt for the electroreduction of oxygen, and they found similar exchange... 

---