Multijunction solar cells

Gramaccio CA, Selvagi A.Galluzzi F(1993) Thin-flim multijunction solar cell for photoelectrolysis. Electochim Acta 38 111-113... 

These early tests were not conducted with the most efficient solar cells available at that time. The record efficiency then was about 30% for a laboratory cell (see Fig. 4) and those cells were not easily obtainable. Today s record efficiency is 40.7%, and 35% efficient cells are commercially available.18 Therefore, 40% solar to hydrogen efficiency is expected in the near term assuming a heat boost of 40%, a multijunction solar cell efficiency of 35%, and an optical efficiency of 85%. A 40% multijunction solar cell would yield a solar to hydrogen conversion efficiency of almost 50%. Nevertheless, electrochemical theoretical results calculated by Licht, shown in Figure 10, are consistent with these predictions based on Solar Systems early experiments.15... 

The existing world s annual production capacity for manufacturing high-efficiency III-V multijunction solar cells is enough today for 1000 MW annually of CPV systems. This level provides a good jumpstart into the market. 

Olson, J.M. Friedman, D.J. Kurtz, S. High-efficiency III-V multijunction solar cells. In Handbook of Photovoltaic Science and Engineering Luque, A., Hegedus, S., Eds. Wiley Chichester, 2003 359 11. 

M.K. Siddiki, et al, A review of polymer multijunction solar cells. Energy Environmental Science, 2010. 3(7) p. 867-883. 

Higher efficiency, higher cost multijunction solar cells, such as the Ill-V materials systems capable of 20-40% PV conversitm efficiency are also commercially available. Using these materials, 14-28% STH would be achievable using PV-electrolysis. In today s market, however, such systems would be prohibitively expensive for any large-scale deployment. The 5-7% mark for lower cost amorphous silicon technology is a more appropriate near-term benchmark for practical solar hydrogen production. Alternative PEC-based schemes need to meet or exceed this benchmark to be viable. 

King, R.R. et al Advances in High-Efficiency ni-V Multijunction Solar Cells. Adv. Opto-Electr. Article ID 29523, 8 pages (2007)... 

The Basic Physics and Design of III-V Multijunction Solar Cells http //photochemistry.epfl. ch/EDEY/NREL.pdf. Accessed 6 Oct 2011... 

T.I. Chappell, The V-groove multijunction solar celL IEEE Trans. Electron Devices 26(7), 1091-1097 (1979)... 

The conversion efficiency of InGaP/GaAs-based multijunction solar cells has been improved in the same way. A schematic illustration of the InGaP/(In)GaAs/Ge triple-junction solar cell reported by Takamoto et al. is shown in Figure 3.14. The device pictured gave an efficiency of 31.5% under standard conditions. ... 

J. M. O. Zide, A. Kleiman-Shwarsctein, N. C. Strandwitz, J. D. Zimmerman, T. T. Steenblock-Smith, A. C. Gossard, A. Forman, A. Ivanovskaya, and G. D. Stucky, 2006, Increased efficiency in multijunction solar cells through the incorporation of semimetallic ErAs nanoparticles into the mnnel junction, Phys. Lett 88,162103... 

King, R.R. Fetzer, C.M. Colter, P.C. Edmondson, K.M. Ermer, J.H. Cotal, H.L. Hojun Yoon Stavrides, A.P. Kinsey, G. Krut, D.D. Karam, N.H., High-efficiency space and terrestrial multijunction solar cells through bandgap control in cell structures. Proc. 29th IEEE Photovoltaic Specialists Conference, IEEE, 2002 776-81. 

Multijunction solar cells divide the solar spectrum into segments of increasing energy. Each junction absorbs a lower portion of this spectrum. These devices have higher efficiencies if each junction performs well but are more sensitive to defect state density. 

---