Solution-Processed Electron-Selective Contacts Enabling 21.8% Efficiency Crystalline Silicon Solar Cells

Crystalline silicon (c-Si) solar cells with carrier-selective passivating contacts have been prosperously developed over the past few years, showing fundamental advantages, e.g., simpler configurations and higher potential efficiencies, compared with conventional c-Si solar cells using highly doped emitters. Herein, solution-processed cesium halides (CsX, X represents F, Cl, Br, I) are investigated as electron-selective contacts for c-Si solar cells, enabling lowest contact resistivity down to about 1 mΩ cm² for slightly doped n-type c-Si/CsF/Al contact. After inserting a thin intrinsic amorphous silicon (a-Si:H(i)) passivating layer, the contact resistivity can still be kept in a low value, about 10 mΩ cm². With full area rear-side a-Si:H(i)/CsF/Al electron-selective passivating contacts, record power conversion efficiencies of about 21.8% are finally demonstrated for n-type c-Si solar cells, showing a simple approach to realize high-efficiency c-Si solar cells.