PEDOT-PSS layer

Fig. 11. Coated film thickness data of the H-dip)-coated EL layer (a) and the PEDOT PSS layer (b) as a function of carrying sp>eed for two gap heights (0.9 and 0.8 mm). The solid curves show the theoretical predictions of the Landau Levich equation. (Park Han, 2009)...

In another study Arias et al. showed that a vertical phase segregation could be induced in thin films spin cast from F8BT PFB blends by interfacial modification of the PEDOT PSS layer with SAMs [241]. To introduce the SAM, the PEDOT PSS layer was first modified by oxygen plasma treatment leading to... 

ITO/PEDOT PSS/CuPc C6o/Mg/Ag organic solar cells were fabricated on ITO (5 Q/squarc sheet resistance)-coated glass substrates. After solvent cleaning, the ITO/glass substrates were spin-coated by a PEDOT PSS layer and immediately transferred into the deposition chamber. A 70 nm-thick CuPc C60 blend layer was prepared by organic vapour phase deposition (OVPD ) [2, 3], The Mg/Ag back contacts were deposited by thermal evaporation in high vacuum (p 10 7 mbar) on non-air-exposed absorber surfaces. The device preparation details can be found elsewhere [4], The compositional and substrate temperature (Tsubstrate) investigations are carried out on type A and B devices with nonoptimised and optimised contacts, respectively. 

Here we show that the polarity of polymer solar cells can be reversed by changing the position of two interfacial layers vanadium oxide (V2O5) layer as hole injection and cesium carbonate (CS2CO3) layer as electron injection, independent of the top and bottom electrodes. ° Since our first demonstration of inverted solar cells, more and more interests have focused on this new architecture. Waldauf et al. demonstrated inverted solar cells with a solution-processed titanium oxide interfacial layer. White et al. developed a solution-processed zinc oxide interlayer as efficient electron extraction contact and achieved 2.58% PCE with silver as a hole-collecting back contact. It is noteworthy to mention that EQE value for inverted solar cells approaches 85% between 500 and 550 nm, which is higher than that of normal polymer solar cells. This is possibly due to (i) the positive effect of vertical phase separation of active layer to increase the selection of electrode and (ii) lower series resistance without the PEDOT PSS layer. 

Based on this composite electrode, PLECs were fabricated by an all-solution process. The PLEC devices were made in four steps. (1) A thin PEDOT PSS layer was spin coated onto AgNW-PUA composite electrode with 15 Qsq sheet resistance as the anode. (2) A solution of a conjugated polymer (Super Yellow) and electrolyte blend was then spin-coated onto the anode. (3) The resulting film was laminated with a second 15 Qsq AgNW-PUA composite electrode (as cathode) to complete the device fabrication. (4) Finally, the device was laminated between a pair of precross-linked urethane liquid rubber compound layers to accomplish the encapsulation. 

The two electrons transferred from TDAE to PEDOT-PSS are expected to undope the conjugated polymer chains. Since TDAE diffuses into PEDOT-PSS, long exposures to the electron donor induce changes in the optical properties of the polymer film. Optical absorption experiments on 200 nm thick PEDOT-PSS films coated onto a transparent polyethylene terephthalate (PET) substrate. The pol5mier film was exposed to the TDAE vapor in an inert nitrogen atmosphere and shows the difference in absorption spectrum between a film exposed to TDAE and the pristine PEDOT-PSS layer (Figs. 3.10 and 3.11). The modification of the optical properties and the sheet resistance of the pol5mier layer were recorded versus exposure time. The two absorption features at 550 nm and... 

A 70 nm thick, smooth and pinhole-free film was successfully printed using a 100 lines/cm and 37 pm cell depth gravure cylinder and modified ink containing 65 wt% of PEDOT PSS, 1 wt% Tween 80, and 34 wt% isopropyl alcohol. The PEDOT PSS layer was subsequently dried at 110 °C with a web speed of 8 m/min. 

FIGURE 3.27 Atomic force microscopy (AFM) images of PEDOT-PSS layers with different sets of L values, (a)... 

Figure 6.2 (a) Schematic of the ESSENCIAL process for fabricating polymer solar cells (al) applying blend solution (a2) active layer formation during solvent evaporation under pressure (a3) isolated island-type electrode deposition on top of polymer blend film after removing the PDMS stamp. Note that PEDOT PSS layer is not indispensable to this processing as described in the text, (b) Roll-to-roll processing for polymer solar cells (bl) schematic of roll-to-roll process for polymer solar cell fabrication (b2) a schematic to depict... 

PCE = 4.40%). The PV cells fabricated by roll-to-roll processing were prepared without PEDOT PSS layer. Reproduced with permission from Ref [47]. Copyright 2008, Wiley-VCH Verlag GmbH. 

In a second commercial antistatic application, PEDOTiPSS was used as the conductive ingredient in an outer surface antistatic layer on cathode ray tubes (CRTs) to avoid dust contamination during manufacture and use. In addition to the same advantages as described above, the PEDOT PSS layer was found to enhance optical contrast in the displays. 

In addition to its roie in the improvement of hole injection, PEDOTiPSS can also effectively smooth the normally rough ITO anode surface, thereby decreasing the occurrence of micro-shorts in OLED devices. Figure 14.14 [139] shows the AFM results demonstrating the decreased roughness of a PEDOT PSS layer on ITO. The improvement in lifetime is attributed mainly to fewer micro-shorts, which manifest in devices as dark spots. 

An interesting approach to the fabrication of PE3X)T-based electrochromic cells is a setup that combines two PEDOT PSS layers [186]. This concept utilizes the nonlinear coloring behavior of PEDOTiPSS and the performance of the device is based on the fact that the sum of the absorptions of the two layers passes through a minimum. The drawback to this dual-layer PEDOTiPSS device, however, is reduced optical contrast. 

Neither the PEDOT PSS layer nor the entire cell was covered by a protective layer, and the cells were exposed to the ambient environment throughout. But in the future, it will be important to cover the cells to protect them from humidity and oxygen, which have an effect on the PEDOT PSS polymer. Protection of the cell is also needed for laundering purposes if the textile garment with the cells in them would need to be washed. Otherwise, when the fabricated devices come into contact with water, the polymer electrolyte is easily dispersed into water, thereby reducing the current loading. 

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