Interface Tuning through the MoO3 Additive in Al Paste to Enhance the Performance of Crystalline Silicon Solar Cells

The efficiency of silicon solar cells is largely affected by the quality of the front and back metallic contacts. In this work, MoO3 is added to the Al paste for the back contact of crystalline silicon solar cells. The MoO3 additive lowers the series resistance of the solar cell from 4.1 to 3.5 mΩ and increases the photoelectric conversion efficiency from 19.26 to 19.54%. We identify that the thermite reaction between MoO3 and Al takes place at about 800 °C and metallic Mo diffuses into the Al–Si solid layer, decreasing the barrier height between Al and Si and lowering the contact resistance. This work demonstrates an approach by optimizing the aluminum-back surface field (Al-BSF) in the back metallic contact of crystalline silicon solar cells to enhance the performance of the cell.