Influence of the energy dependence of the absorption coefficient on the solar energy conversion efficiency

In most cases, when the efficiencies of a single or multi-gap (with intermediate bands) solar cell are evaluated, the energy dependence of the absorption coefficients is ignored. In this work we will evaluate the range of optical thickness and average absorption coefficients in which this dependence should be considered. For this study we use different absorption coefficients generated randomly as a function of the energy. In many practical cases, the efficiencies are lower than those expected.