Multijunction photovoltaic cell

Figure 4.53. Schematic of (a) a single-junction and (b) multijunction photovoltaic cell.

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. 

Present solid-state (photovoltaic) mul-tijunction photovoltaics exist in one of two modes, either splitting (in which the solar spectrum is optically separated before incidence on the cells) or stacked devices. The latter mode has been developed as either monoKthic (integrated) or mechanically (discrete cells layered with transparent adhesive) stacked cells. Most monoKthic stacked multijunction photovoltaics under development use III-V semiconductors in at least one of the layers and take advantage of the variations in band gap and close lattice match achieved with other related III-V alloys. For example, GalnP has been used as a wide gap top cell, or GaSb and GalnAsP as small gap lower cells, for III-V top-layer multijunction cells other cells use silicon or CIS cells as a lower layer [12-15]. 

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 cell technology developed by the photovoltaic industry is being used to develop photo-electrochemical light harvesting systems that generate sufficient... 

Rocheleau, R.E., Vierthaler, M. 1994. Optimization of multijunction a-Si H solar cells using an integrated optical/electrical model, in Proceedings of the 21st World Conference on Photovoltaic Energy Conversion, pp. 567-570. Institute for Electrical and Electronics Engineers, Honolulu, HI. 

G-15 Best research cell efficiencies for multijunction concentrator, thin-film, crystalline silicon, and emerging photovoltaic technologies, 236... 

Yamaguchi M. (2001), Super-high efficiency III-V tandem and multijunction cells , in Archer M. D. and Hill R., eds., Clean Electricity from Photovoltaics, Series on Photoconversion of Solar Energy, Imperial College Press, London, pp. 347-375. 

Multijunction Device - A high-efficiency photovoltaic device containing two or more cell junctions, each of which is optimized for a particular part of the solar spectrum. 

Most of the technological development effort in photovoltaics has been directed at inorganic semiconductor photovoltaics, which can achieve power conversion efficiencies for single junction devices, for example, GaAs, of up to 29 % and over 37 % in multijunction devices [3]. These cells, albeit being very efficient, tend to require complex and expensive fabrication protocols, which make them expensive to produce, and environmentally costly, in terms of the energy input and waste produced during manufacture. 

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