The Effect of Work Function of Back Contact Metals on the Performance of CdTe Solar Cells

Mohammed M Aliyu
2024-05-17 317 views 1 downloads

 

The CdTe thin film solar cells suffer power losses at the back contact due to charge losses due to poor mismatch of the work function of interfacing back contact materials. Thus, there is a need to find appropriate back contact materials that do not reduce cell performance by creating large Schottky barriers. One of the established strategies employed to reduce the barrier height is depositing metal(s) with high work function to the CdTe back surface. In this study, we used the average of the commonly reported values of the work function of metals, to investigate the effects of various metals, when used as back contacts, on the performance of CdTe solar cells. Without any other strategy employed to overcome the Schottky contacts, the solar cells' efficiency is gravely diminished when metals with work functions lower than 5.0 eV are used. While metals like Pt, Pd, and Au with very high work functions produce cells with efficiencies of up to 18.6%, lower work functions metals like Al almost completely diminished the efficiency to less than 0.5%. our findings indicate that the Schottky barrier affects mainly Voc and FF, as Jsc showed only a slight reduction. When subjected to extreme operating temperatures, the efficiencies largely decreased with temperature. Temperature coefficients of -0.3 to -0.45/°C have been obtained, for the highest-performing metals,

 

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