Polymer-based counter electrodes

Polymer-Based Counter Electrodes with Printable Materials... 

Saranya, K., Rameez, M., Subramania, A., 2015. Developments in conducting polymer based counter electrodes for dye-sensitized solar cells-an overview. Eur. Polym. J. 66,207-227. 

GQDs/Conjugated-Polymer-Based Counter Electrode for Dye-Sensitized Solar Cells... 

Consider the polymer-on-metal interface, which might be prepared by coating a thin metal film with polymer in a polymer-based LED. The case of the counter electrode, formed by vapor-deposition, is discussed subsequently. First, assume that the substrates have clean surfaces hydrocarbon and oxide free, or naturally oxidized but still hydrocarbon free (pointed out as necessary). Typically, in connection with polymer-based LEDs, the metallic substrate could be gold, ITO (indium tin oxide) coated glass, the clean natural oxide of aluminum ( 20 A in thickness), the natural oxide which forms upon freshly etched Si( 110) wafers ( 10 A), or possibly even a polyaniline film. Dirt , which may be either a problem or an advantage, will not be taken up here. Discussions will alternate between coated polymer films and condensed model molecular solid films, as necessary to illustrate points. 

Foulds and Lowe (1986) combined mass production of the base sensor and enzyme immobilization as follows. Using gold or platinum ink, a working and counter electrode were deposited on a ceramic substrate. After thermal treatment of the electrode material a solution containing GOD and a pyrrole derivative of ferrocene was electrochemically polymerized at the electrode. The pyrrole component forms a conducting polymer and the immobilized ferrocene acts as electron acceptor for GOD. The structured immobilization permits this technique to be used for successive enzyme fixation to multiparameter sensors. 

There are two kinds of polymer material that used in quasi-solid/solid state DSSCs. For quasi-solid electrolytes, polyionic liquids have been proposed as solvent and redox couple as solute. They appear in molten salts and present many promising properties, such as, high chemical and thermal stability and high ionic conductivity Their main drawback is related to its high viscosity, which makes the ions diffusion rather slow. As the transport of ions to the counter electrode in an ionic liquid matrix represents a rate-limiting step in DSSC (Bella, 2015), the performance of quasi-solid electrolytes based solar cell is imsatisfled. 

As a critical component of the DSSC, counter electrode is also a key to the flexibility of the device. Some flexible conductive materials, such as conducting polymers, carbon-based nanomaterials and their composites have been employed as flexible counter electrodes to replace the Pt electrode in the fabrication of flexible DSSCs. For instance, after coating with conducting polymer PEDOT, a flexible counter electrode was developed with low sheet resistance and served as an ideal candidate in replacement of the conventional Pt counter electrode (Fig. 9.1B) (Mozer et al., 2010). 

FIGURE 9.1 Flexible solar cells based on different kinds of polymer substrates. (A) Photograph of a flexible DSSC based on ITO-coated PET substrate wrapped on a pen. (B) Schematic illustration of the layer structure of a solid-state DSSC based on PEDOT on Goretex film as a counter electrode. (C) Schematic illustration (left) and photograph (right) of the PSC based on ITO-coated PET substrate. (D) Comparison of PSCs fabricated on conventional FTO/glass and flexible PEDOT PSS/PET substrate. (E) Schematic illustration of the flexible solar cell based on Ag-grid/PET substrate. 

Aitola, K., Borghei, M., Kaskela, A., Kemppainen, E., Nasibulin, A.G., Kauppinen, E.I., Lund, P.D., Ruiz,V., Halme, 2012. Flexible metal-free counter electrode for dye solar celk based on conductive polymer and carbon nanotubes. J. Electroanal. Chem. 683,70-74. 

Electrospinning based on the application of a static electric field on a polymer solution or melt through a spinneret appears to be a simple and well-controllable technique able to produce polymeric nanofibers. A typical experimental setup is based on a capillary injection tip, a high-voltage source able to apply electric fields of 100-500 KVm , and a metallic collector, or counter electrode. Electric current in electrospinning experiments is usually in the order of a few milliamperes. ... 

The feasibility of the gel electrolytes for lithium-ion batteries development has been tested by first examining their compatibility with appropriate electrode materials, i.e., the carbonaceous anode and the lithium metal oxide cathode. This has been carried out by examining the characteristics of the lithium intercalation-deintercalation processes in the electrode materials using cells based on the given polymer as the electrolyte and lithium metal as the counter electrode. 

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