DSSC cells

Relatively little is understood in the presence of non planar-non ideal interfaces, where electronic levels located in the band gap region act as recombination centers. Colloidal materials, low cost polycrystalline materials and films, interpenetrating networks of absorber and charge collecting phases (e.g., as in the DSSC cells), and the presence of redox active adsorbing species, all give rise to... 

Polo and Murakami Iha used anthocyanins extracted from jaboticaba (Myrciaria cauliflora Mart) and calafate (Berberis buxifolia Lam) as dyes for DSSCs. [46] The interaction between the dye molecules and Ti02 was identified by comparing the visible absorption spectra of the bare dye in solution with those acquired after dye absorption on the semiconductor a 15 nm red shift indicated the anchorage of the anthocyanin molecules on the Ti02 nanoparticles. The inorganic semiconductor layer was deposited on ITO and the electrolyte employed was I /I3 dissolved in acetonitrile. The photovoltaic cell obtained with the jaboticaba extract gave an IPCE value of 0.2 with a short-circuit current (/sc) of 7.2 mAcm 2, a Voc of 0.5 V and a fill factor of 54%. 

Thus electrical power is produced without any permanent chemical change. The overall performance of the DSSC depends on the energy levels of certain of the components of the cell, namely ... 

The DSSC differs substantially from the p-n-junction solar cell because electrons are injected from the photosensitiser into the CB of the semiconductor and no holes are formed in the VB of the semiconductor. 

Scientific interest in nanocarbon hybrid materials to enhance the properties of photocatalysts and photoactive electrodes has been growing rapidly [1-8]. The worldwide effort to find new efficient and sustainable solutions to use renewable energy sources has pushed the need to develop new and/or improved materials able to capture and convert solar energy, for example in advanced dye-sensitized solar cells - DSSC (where the need to improve the photovoltaic performance has caused interest in using nanocarbons for a better cell design [9,10]) or in advanced cells for producing solar fuels [11-13]. 

Previous sections have demonstrated how nanocarbon-semiconductor hybrid materials provide a number of potential advantages for the development of advanced devices for a sustainable use of renewable energy. Two of the more relevant areas are (i) to improve the performances of DSSCs and (ii) to develop novel cells for producing solar fuels. 

Fig. 17.5 Scheme of basic processes occurring in DSSCs (a) and organic solar cells (c). (b) Band bending for an n-type semiconductor and a p-type semiconductor in equilibrium with an electrolyte. 

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... 

The current energy conversion efficiencies for a DSSC are 11.1% for an aperture area of 0.219 cm, and 6.8% for a larger cell with an aperture area of 101 cm [79]. The energy conversion... 

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