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Chapter 8 • Photovoltaics: The Basics 171
FIGURE 8.20 Irradiative power converted in carrier generation. (A) InGaP (W g = 1.7 eV). (B) Germanium (W g = 0.67 eV).
(C) Tandem of InGaP and Ge.
Table 8.1 Efficiency Limits of Multimaterial Structures
Number of Cells Efficiency (%) Bandgap (eV)
1 33 1.36
2 45 1.63; 0.74
3 51 2.02; 1.21; 0.59
4 55 2.31; 1.55; 0.99; 0.5
ways for overcoming the Quasier–shockley limit using tools of material engineering that
will be discussed in more details in Chapter 13.
8.4.2 Wafer-Based and Thin Film Construction
As follows from eqs. (8.5), (8.24)–(8.26), the cell construction with respect to individual
layer thicknesses strongly depends on the absorption coefficient with photon energy in
the solar cell material (Fig. 8.3 and Fig. 8.21).
