Photovoltaics hybrid cells

In this chapter, I give an account of the historical development of semiconductor photoelectrochemistry and nanostructured photovoltaic devices in Section 1.2, and then Sections 1.3-1.6 provide a brief introduction to the major cell types discussed in the remainder of the book the ETA (extremely thin absorber) cell, organic and hybrid cells, dye-sensitised solar cells (Gratzel cells) and regenerative solar cells. 

Schlettwein, Yoshida, and Lincot provide a critical review of the research literature on porous zinc oxide sensitized by organic dyes, and the potential use of these materials for the development of large-scale photovoltaic solar cells. An introduction is provided to the electrodeposition of zinc oxide thin films, their means of sensitization by a variety of organic molecules, and their preparation by one-step deposition from solutions containing water-soluble dyes to produce hybrid materials suitable for solar cell. The advantages of various substrates for large-scale cells are discussed for plastic and textile materials. 

In any case, it is perceived from the above discussion that the problem of longterm chemical stability of polycrystalline semiconductor liquid junction solar cells is far from being solved. Still, as already pointed out in the early research, any practical photovoltaic and PEC device would have to be based on polycrystalline photoelectrodes. Novel approaches mostly involving specially designed PEC systems with alternative solid or gel electrolytes and, most importantly, hybrid/sensitized electrodes with properties dictated by nanophase structuring - to be discussed at the end of this chapter - promise new advances in the field. 

Lira-Cantu, M. Krebs, F. C. 2005. Polymer photovoltaics From conjugated polymers to hybrid organic-inorganic solar cells. Recent Res. Dev.Appl. Phys. 8 71-98. 

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]. 

The goal of polymers in photovoltaic cells is to make very cheap active materials even if their efficiency is very low. So, a cheap mass-production process could lead to domestic and industrial applications. Some research dates back 20 years and today several techniques are competing, with either hybrid or all-polymer systems. Among the various methods we can quote as examples ... 

Xue JG, Rand BP, Uchida S, Eorrest SR (2005) A hybrid planar-mixed molecular heterojunction photovoltaic cell. Adv Mater 17 66... 

Xue JG, Uchida S, Rand BP, Forrest SR (2004) Asymmetric tandem organic photovoltaic cells with hybrid planar-mixed molecular heterojunctions. Appl Phys Lett 85 5757... 

Two principal applications of conjugated oligomers (polymers)-NCs composites or hybrids as components of electronic devices can be envisioned in photovoltaic cells (PCs) and in light emitting diodes (LEDs). Both applications will be discussed below. 

Scheme 5.9 Scheme of a hybrid photovoltaic cell with an active layer consisting of a composite of a conjugated polymer and semiconductor nanocrystals (so-called bulk heterojunction). 

Huynh WU Dittmer JJ Teclemariam N Milliron DJ Altvisatos AP Barnham KWJ, Charge transport in hybrid nanorod-polymer composite photovoltaic cells, Rhys. Rev. B, 2003, 67, 115326. 

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