Crystalline silicon solar cells efficiencies

Germane is used, along with silane, SiH4, to make amorphous or crystalline silicon solar cells having an extended solar energy absorption range to increase conversion efficiency. 

The influence of interface area on Voc is utilized in high efficiency crystalline silicon solar cells with the so-called point contact concept to increase the open circuit voltage by suppressing area related recombination [149], Recently, the point contact concept has been applied also in pc-Si H solar cells using photolithography or self-organized zinc oxide etch masks [150], However, so far Voc improvement could not be demonstrated. For more details of preparation and application of ZnO etch masks the reader is referred to the original work [118]. 

Among the various materials, silicon, which accounts for more than 90% of solar cells today, is undoubtedly the key, especially if we consider a large-scale deployment. To accelerate the deployment of photovoltaic technology by development of high-efficiency crystalline silicon solar cells, the Institute for Materials Research (IMR), Tohoku University, organized a unique domestic workshop in 2004 and 2005 to discuss the approach from the view point of... 

Petermann JH, Ohrdes T, Altermatt PP, Eidelloth S, Brendel R (2012b) 19% efficient thin-film crystalline silicon solar cells from layer transfer using porous silicon a loss analysis by means of three-dimensional simulations. IEEE Trans Electron Devices 59(4) 909-917 Poortmans J, Beaucame G, Sivoththaman S (2000) Study of Si deposition in a batch-type LPCVD-system for industrial thin-film crystalline Si solar cells. In Conference record of the twenty-eighth IEEE photovoltaic specialists conference - 2000 (Cat. No.00CH37036), Anchorage, 2000. IEEE, New York, pp. 347-350... 

Thin-film solar shingles used on residential roofs today are only about 5 to 8% efficient. The efficiency of solar towers is also about 5%. Photovoltaic (PV) cell efficiencies range from about 5% for amorphous silicon (A-Si) designs, 9% to 10% for CdTe modules, and 13% to 16% for crystalline silicon modules. SEGS efficiencies are between 10 and 25%. 

The cell efficiency of a single crystalline Si solar cell reaches 18- 0 % in the mass production line. The poly crystalline and cast Si solar cell shows 15-18% on average. The cell efficiency of amorphous Si solar cells (a-Si) is 8-9 %. Silicon solar cell generates electric power of direct current with about 1 V, a few combinations of which are suitable to apply to water-electrolysis. Therefore, if Si solar cell is combined with SPE, the system efficiency will be 10 % in practical use. This value is the highest among the systems which produce hydrogen with use of renewable energies as will be described here in-below. 

Petermann H, Zielke D, Schmidt J et al (2012) 19 %-Efficient and 43 pm-thick crystalline Si solar cell from layer transfer using porous silicon. Prog Photovol Res Appl 20 1-5 Pickering C, Beale M, Robbins D, Pearson R, Greef R (1984) Optical studies of the stmcture of porous silicon films formed in p-type degenerate and non-degenerate silicon. J Phys C 17 6535-6552... 

Single-Crystal Silicon. Silicon is still the dominant material in photovoltaic. It has good efficiency, which is 25% in theory and 15% in actual practice. Silicon photovoltaic devices are made from wafers sliced from single crystal silicon ingots, produced in part by CVD (see Ch. 8, Sec. 5.1). However, silicon wafers are still costly, their size is limited, and they cannot be sliced to thicknesses less than 150 im. One crystalline silicon wafer yields only one solar cell, which has an output of only one watt. This means that such cells will always be expensive and can only be used where their high efficiency is essential and cost is not a major factor such as in a spacecraft applications. 

Because of its indirect bandgap, bulk crystalline silicon shows only a very weak PL signal at 1100 nm, as shown for RT and 77 K in Fig. 7.9. Therefore optoelectronic applications of bulk silicon are so far limited to devices that convert light to electricity, such as solar cells or photodetectors. The observation of red PL from PS layers at room temperature in 1990 [Cal] initiated vigorous research in this field, because efficient EL, the conversion of electricity into light, seemed to be within reach. Soon it was found that in addition to the red band, luminescence in the IR as well as in the blue-green region can be observed from PS. 

Crystalline solar cells are heavy and expensive to manufacture. However, their efficiency in converting sunlight has historically been superior to thin-film. Crystalline cells are constructed with silicon semiconducting materials. 

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