Fabrication of DSSC

Attempts have been made to replace the components with new electrode materials, alternative sensitizers and different types of electrolytes. In most cases studies were aimed at achieving advanced properties and applying DSSC in order to meet the requirements of commercial applications and/or to reduce the production cost. An important issue in cost reduction is the fabrication of DSSC on flexible, transparent, conductive plastic substrates [190-192]. The nanocrystalline Ti02 film is considered to be the most promising material for the electrode of dye-sensitized solar cells to generate high performance [193-195]. 

Successive cycles of thiophene terminal bromination and Suzuki-type coupling reactions with 3-hexylthiophene-2-boronic ester gave intermediate ter- and quaterthiophenes. Formylation of these intermediates and final condensation with cyanoacetic acid in basic medium afforded corresponding oligothiophenes in 70-90% yields. UV-Vis absorption spectra of 2.82 (n = 1, 2) showed maxima at 463 and 473 nm, respectively. Fabrication of DSSCs based on 2.82 (n = 1, 2) showed a high incident photon-to-current conversion efficiency (IPCE) of 70 % in the range 400-650 nm and good maximum power conversion efficiencies of 7.7 and 5.6% under AM 1.5 illumination. 

It was shown that organic dyes can be attached to the titanium dioxide surface indirecfiy using suitable organic mediators. The most illustrative was the fabrication of DSSCs using complicated porphyrin-ferrocene dyad as a dye. This dyad possesses no carboxyl groups capable of direct bonding to the titanium dioxide. Therefore,... 

The second approach involving the use of ionic liquids in polymer electrolyte-based DSSC consists of the use of ionic polymers. " The ionic liquid-type polymer may have the desirable properties (similar to that of pure ionic liquids) and be employed in the fabrication of DSSC with high efficiency, without the problems of evaporation or leakage of the electrolyte during long-term operation. 

During recent decades, research efforts have focused on the development of DSSCs. Their advantages include use of cheap materials, ease of device fabrication, high stability, and reasonably high efficiencies of currently around 11-13 % [9,10,13-... 

Methods have been developed for fabrication of the highly-ordered titania nanotuhe arrays from titanium thin films atop a substrate compatible with photolithographic processing, notably silicon or FTO coated glass [104]. The resulting transparent nanotuhe array structure, illustrated in Fig. 5.16, is promising for applications such as anti-reflection coatings and dye sensitized solar cells (DSSCs). Fig. 5.17 shows the typical anodization behavior of a 400 nm Ti thin film anodized at 10 V in an HE based electrolyte. Eor a fixed HE concentration, the dimensions of the tube vary with respect to... 

Low production cost. The production procedure of DSSC is relatively simple and the materials for DSSC are relatively inexpensive. Fabrication costs will, therefore, be less than that of conventional solar cells. For example, the estimated production cost, 0.60 US /Wp for a DSSC with 10% efficiency, is quite competitive with those of conventional solar cells [11,12]. 

Figure 19 Continuous process for the fabrication of monolithic series connecting DSSC modules. (From Ref. 16.)...

Despite the extensive application of ruthenium complexes in DSSC, transition metal containing polymers have received relatively little attention in the fabrication of polymeric photovoltaic cells. Most of the early works on ruthenium containing polymers were focused on the light-emitting properties.58-60 Several examples of ruthenium terpyridine/bipyridine containing conjugated polymers and their photoconducting/electroluminescent properties were reported.61,62... 

In commercial terms, the main advantage that DSSCs have over silicon p-n junction cells is that their cost per watt could be four to five times lower, because of their lower-cost materials and construction techniques. Moreover, the efficiency of DSSCs falls off less in low-intensity light or with increasing temperature than that of Si cells, and they have lower embodied energy i. e. less energy is required to make them). DSSCs can also be fabricated as translucent panels or laid down as flexible films on non-planar surfaces. 

For fabrication of a full plastic DSSC, the plastic counter electrode needs to show high performance in keeping with a high-density photocurrent, with characteristics close to those of a platinum counter electrode. 1-V characteristics of plastic DSSCs have been examined. An electrolyte composition of 0.4M Lil, 0.4M TBAI, 0.04M I2, and 0.3 M N-methylbenzimidazole (NMB) in acetonitrile (AN)/MPN (1 1 by volume) was used and N719 as a dye sensitizer of the Ti02 photoanode the 1-V curves are compared in Figure 3.7 for PEDOT-PSS-based counter electrodes and a standard platinum sputtered electrode [29]. 

Fabrication of counter electrodes by simple coahng processes using PEDOT-based printable pastes as described here is an important key for DSSC manufacture with respect to minimum costs and rapid production. Design of semi-transparent counter electrodes also contributes to improved hght uhlization of the flexible ceU and modules. 

Fabrication of Large-Area Plastic DSSC Modules... 

Fabrication of Large-Area Piastic DSSC Moduies 213... 

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). 

The photovoltaic performance of DSSC can be analyzed in terms of conversion yield and long-term stability. For metal complex-based DSSCs, the polypyridyl complexes of ruthenium and osmium are known to fulfill both criteria [29]. After the solar cell has been fabricated, it has to be evaluated for a number of parameters such as IPCE (or quantum efficiency), /sc (short-circuit current), Voc (open-circuit voltage), FF (fill factor), and rj (power conversion efficiency), which provide performance information for real-world applications. These DSSC parameters can be determined using a solar light simulator. The fill factor can assume values between 0 and less than 1 and is defined by the ratio of the maximum power (P,aax) of the solar cell per unit area divided by the and according to [7]... 

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