Solar cell applications

The optical properties of a-Si H are of considerable importance, especially for solar-cell applications. Because of the absence of long-range order, the momentum k is not conserved in electronic transitions. Therefore, in contrast to crystalline silicon, a-Si H behaves as though it had a direct bandgap. Its absorption coefficient for visible light is about an order of magnitude higher than that of c-Si [74]. Consequently, the typical thickness (sub-micrometer) of an a-Si H solar cell is only a fraction of that of a c-Si cell. 

Of course, the design and the development of new redox couples for solar cell applications is a challenging task because it has to meet several critical requirements ... 

For solar cell applications, doping of CuInSe2 with Ga (CIGS) yields vacuum-evaporated absorber layers that produce solar cells with the highest... 

Jiang, C.-W. Green, M. A. 2006. Silicon quantum dot superlattices Modeling of energy bands, densities of states, and mobilities for silicon tandem solar cell applications. J. Appl. Phys. 99 114902-114909. 

Polycrystalline GaN UV detectors have been realized with 15% quantum efficiency [4], This is about 1 /4 of the quantum efficiency obtained by crystalline devices. Available at a fixed price, however, their increased detection range may well compensate their lack in sensitivity. Furthermore, new semiconductor materials with a matching band gap appear as promising candidates for UV detection if the presumption of the crystallinity is given up. Titanium dioxide, zinc sulfide and zinc oxide have to be mentioned. The opto-electronic properties and also low-cost production processes for these compound semiconductors have already been investigated to some extent for solar cell applications [5]. 

Figure 8 Patented 5-5 bicyclic ring compounds for solar cell applications.

J. Phys. Chem. C (8) Boschloo, G. Edvinsson, T. Hagfeldt, A. Dye-sensitized nanostructured ZnO electrodes for solar cell applications. In Nanostructured Materials for Solar Energy Conversion Soga, T., Ed. Elsevier Amsterdam, 2007 pp 227-254. ... 

Tang YB, Lee CS, Xu J et al (2010) Incorporation of graphenes in nanostructured Ti02 films via molecular grafting for dye-sensitized solar cell application. ACS Nano 4 3482-3488... 

As mentioned earlier, the DSSC is a very attractive and promising device for solar cell applications that has been intensively investigated worldwide, and its photovoltaic mechanism has also intensively investigated [11-20]. Moreover, commercial applications of the DSSC have been under investigation. In this chapter, we describe the DSSC, including its component materials, structure, working mechanism, efficient preparation procedure, current researches, and long-term stabilities. We also introduce the subjects for improvement of its performance and commercial applications. 

This is considerably different from the recombination reaction with, for example, typical ruthenium dyes. This slow re-reduction of the dyad is explained by the low redox potential of the osmium center, the value of 0.66 V (vs. SCE) observed, points to a small driving force for the redox process. This observation is important for the design of dyes for solar cell applications. Osmium compounds have very attractive absorption features, which cover a large part of the solar spectrum. However, their much less positive metal-based oxidation potentials will result in a less effective re-reduction of the dyes based on that metal and this will seriously affect the efficiency of solar cells. In addition, for many ruthenium-based dyes, the presence of low energy absorptions, desirable for spectral coverage, is often connected with low metal-based redox potentials. This intrinsically hinders the search for dyes which have a more complete coverage of the solar spectrum. Since electronic and electrochemical properties are very much related, a lowering of the LUMO-HOMO distance also leads to a less positive oxidation potential. 

Zinc Oxide Grown by CVD Process as Transparent Contact for Thin Film Solar Cell Applications... 

In the following, each step will be described, both for the AP-CVD and for the LP-CVD cases. The results presented are focused on those properties of ZnO films that are useful for thin film solar cell applications, i.e., transparency, conductivity, and light scattering capability. The last part of paragraph 6.2 comments briefly on alternative methods of CVD processes that have been investigated for ZnO deposition (PE-CVD, photo-CVD,. ..). 

AP-CVD ZnO Hu and Gordon [10,27,29] defined the average visible absorption of ZnO films for solar cell applications as... 

This book is devoted to the properties, preparation and applications of zinc oxide (ZnO) as an transparent electrode material. It focuses on ZnO for thin film solar cell applications and hopefully inspires also readers from related fields. The book is structured into three parts to serve both as an overview as well as a data collection for students, engineers and scientists. The first part, Chaps. 1-4, provide an overview of the application and fundamental material properties of ZnO films and their surface and interfaces properties. Chaps. 5-7 review thin film deposition techniques applied for ZnO preparation on lab scale but also for large area production. Finally, Chaps. 8 and 9 are devoted to applications of ZnO in silicon- and chalcopyrite-based thin film solar cells, respectively. One should note that the application of CVD grown ZnO in silicon thin film cells is discussed earlier in Chap. 6. 

Examine the elements in green boxes bordering the stair-step line in Figure 6-7. These elements are called metalloids, or semimetals. Metalloids are elements with physical and chemical properties of both metals and non-metals. Silicon and germanium are two of the most important metalloids, as they are used extensively in computer chips and solar cells. Applications that make use of the properties of nonmetals, transition metals, and metalloids are shown in Figure 6-8. Do the CHEMLAB at the end of this chapter to observe trends among various elements. 

Papageorgiou N, Athanassov Y, Armand M, et al. The performance and stabihty of ambient temperature molten salts for solar cell applications. J. Electrochem. Soc. 1996. 143, 3099-3108. 

For solar cell applications, thin film LPE is economically viable only if it is combined with a low-cost multicrystalline Si substrate (high-throughput silicon ribbons, upgraded metallurgical grade silicon MG-Si) or with a foreign substrate (glass, ceramic, metallic sheet... see section 9-7). 

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