Silicon solar cells

Fig. 3. Basic design of a commercial silicon solar cell.

Schropp, R.E.l. and Zeeman, M. (1998) Amorphous and Microcrystalline Silicon Solar Cells (Kluwer Academic Publishers, Dordrecht). 

Gordon, R. G, Proscia, J., Ellis, F., and Delahoy, A., Texture Tin Oxide Films Produced by Atmospheric Pressure Chemical Vapor Deposition from Tetramethyltin and Their Usefulness in Producing Light Trapping in Thin Film Amorphous Silicon Solar Cells, >/or Energy Materials, (18) 263-281 (1989)... 

Silicon solar-cells are fabricated using silicon discs in a manner similar to that described previously for manufacture of integrated circuits. The basic external structure used in solar cells is shown in the following diagram ... 

We have already mentioned amorphous silicon solar cells. New processes have been developed to manufacture solar cells based upon deposition of very thin films of photosensitive materials. Such processes have a distinct cost advantage since once the films are deposited, little further processing is needed to form the final solar cell module. 

Schropp and Zeman [11] have classified current production systems for amorphous silicon solar cells. They argue that cost-effective production of solar cells on a large scale requires that the product of the deposition time needed per square meter and the depreciation and maintenance costs of the system be small. Low... 

FIG. 72. Schematic cross-section of (a) a single junction p-i-n o-Si H superstrata solar cell and (b) a tandem solar cell structure. (From R. E. I, Schropp and M. Zeman. "Amorphous and Microcrystalline Silicon Solar Cells—Modeling, Materials and Device Technology," Kluwer Academic Publishers, Boston, 1998, with permission.)... 

R. E. I. Schropp and M. Zeman, Amorphous and Microcrystalline Silicon Solar Cells—Modeling, Materials and Device Technology. Kluwer Academic Publishers, Boston, 1998. 

Ideally, all photons with a wavelength of about 900 nm or shorter should be harvested and converted to electric current. This limit is derived from thermodynamic considerations showing that the conversion efficiency of any single-junction photovoltaic solar converter peaks at approximately 33% near the threshold energy of lAeV.1 2 There are numerous ways to convert the solar radiation directly into electrical power or chemical fuel. The silicon solar cell is the most efficient in this respect. Nevertheless, the capital cost of such devices is not attractive for large-scale applications. 

Assuming that an efficient D-A type of molecule can be synthesized, it should be possible to deposit these molecules as a monolayer onto a glass slide coated with a metal such as aluminum or a wide bandgap semiconductor such as Sn(>2. With the acceptor end of the molecule near the conductor and with contact to the other side via an electrolyte solution it should be possible to stimulate electron transfer from D to A and then into the conductor, through an external circuit and finally back to D through the electrolyte. This would form the basis of a new type of solar cell in which the layer of D-A molecules would perform the same function as the p-n junction in a silicon solar cell (50). Only the future will tell whether or not this concept will be feasible but if nature can do it, why can t we ... 

Schropp, R. E. I. Carius, R. Beaucarne, G. 2007. Amorphous silicon, microcrystalline and thin-film polycrystalline silicon solar cells. MRS Bull. 32 219-223. 

Gangopadhyay et al.48 used a CBD ZnS antireflection coating on large-area commercial monocrystalline silicon solar cells, resulting in a 13.8% efficiency. Ennaoui et al.49 deposited CBD Zn(Se,OH)x films on Cu(In,Ga)(S,Se)2. They reported an active-area efficiency of up to 15.7% and a total-area efficiency of up to 13.26% for such devices. 

Gangopadhyay, U. Kim, K. Mangalaraj, D. Junsin, Y. 2004. Low cost CBD ZnS antireflection coating on large area commercial mono-crystalline silicon solar cells. Appl. Surf. Sci. 230 364-370. 

Curtis, C. J. Rivkin, T. Miedaner, A. Alleman, J. Perkins, J. Smith, L. Ginley, D. S. 2002. Direct-write printing of silver metallizations on silicon solar cells. Mater. Res. Soc. Symp. Proc. 730 79-84. 

F.R. Zhu, T. Fuyuki, H. Matsunami, and J. Singh, Assessment of combined TCO/metal rare contact for thin film amorphous silicon solar cells, Sol. Energy Mater. Sol. Cells, 39 1-9, 1995. 

The satellite would need 50 to 100 square kilometers of collector area using 14% efficient monocrystalline silicon solar cells. More expensive triple junction gallium arsenide solar cells with an efficiency of 28% would reduce the collector area by half. In both cases the solar station s structure would be several kilometers wide, making it much larger than most manmade structures on Earth. Building structures of this size in orbit has never been attempted before. 

S. Kolodinski, J.H. Werner, T. Wittchen, H.J. Queisser, Quantum efficiencies exceeding unity due to impact ionization in silicon solar cells, Appl. Phys. Lett. 63 (1993) 2405-2407. 

Figure 11.4 Principle of operation of a silicon solar cell. 

For more details on the roles of metal impurities in silicon solar cells and efforts to engineer materials that are less affected by these impurities, see S. Dubois, O. Palais, M. Pasquinelli, S. Martinuzzi, and C. Jassaud, J. Appl. Phys. 100 (2006), 123502, and T. Buonassisi, A. A. Istratov, M. A. Marcus, B. Lai, Z. H. Cai, S. M. Heald, and E. R. Weber, Nature Materials 4 (2005), 676. 

Lin GH, Kapur M, Kainthla RC, Bockris JOM (1989) One step method to produce hydrogen by a triple stack amorphous silicon solar cell. Apl Phys Lett 55 386-387... 

Carlson DE, Wronksi CR (1976) Amorphous silicon solar cell. Appl Phys Lett 28 671-673... 

Carlson DE (1989) Amorphous silicon solar cell. IEEE Trans Electron Devices 36 2775-2780... 

Currao A, Reddy VR, van Veen MK, Schropp REI, Calzaferri G (2004) Water splitting with silver chloride photoanode and amorphous silicon solar cell. Photochem Photobio Sci 3 1017-1025... 

Green MA (1993) Silicon solar-cells - evolution, high-efficiency design and efficiency enhancements. Semicond Sci Technol 8 1... 

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