Figure of merit for front electrodes of solar cells

•EQE values and AM1.5 spectrum data are brought into the proposed figure as weight factors.•The proposed figure FH(k) is proven to be suitable in photovoltaic field by simulation process.

Conventional figures of merit often characterize the optical and electrical properties of transparent conductive thin films and are widely applied in research and industry. However, an appropriative figure is necessary to evaluate the front electrodes of solar cells. So an appropriate figure of merit is therefore proposed in this paper, specifically designed for the evaluation of the front electrodes of solar cells. The proposed figure is adapted from ΦTC, the most commonly used conventional figure of merit, with two changes. First, external quantum efficiency functions for different types of solar cells are explicitly considered. Second, data from the air mass 1.5 spectrum are used as weight factors to calculate the mean optical transmittance. With these two changes, the proposed figure of merit is shown to be well adapted to the photovoltaic field. To validate it, silicon heterojunction solar cells with different front electrodes were simulated as examples. By comparing the simulation results and the respective values of the proposed figure, it is evident that this figure of merit provides values that are proportional to the conversion efficiencies of solar cells. The proposed figure can therefore be used in the selection and manufacturing of front electrodes of solar cells. In addition, two variations on this figure of merit are proposed, specifically adapted to the characteristics of multiple electron-hole pairs cells and thermophotovoltaic cells.

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