Effects of the Band Gap Width of Emitter Materials and the Front Surface of the Top Electrode on the Performance of TOPCon Solar Cells

The width of the top electrode of the battery can represent the metal coverage of the front surface of the solar cell, that is, the greater the width of the top electrode of the battery, the higher the metal coverage of the front surface of the battery. Therefore, in this work, by changing the width of the top electrode of TOPCon battery, the influence of metal coverage on the performance of the battery is explored. Considering the conversion efficiency of the battery and the actual production process, this paper thinks that 2 % metal coverage on the front surface is the most suitable. Subsequently, in order to reduce the optical limitation of the emitter and improve the overall efficiency of tunnel oxide passivation contact (TOPCon) solar cells, six kinds of emitter materials with different band gap widths are used to simulate the TOPCon solar cells: GaSb, polysilicon, InP, <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{CuO}_{2}$</tex>, AlAs and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{CuAlO}_{2}$</tex>. The influence of the band gap width of emitter materials on the performance of solar cells and its potential mechanism are deeply discussed. The results show that with the increase of the band gap width of the emitter material, the short-circuit current density and filling factor increase at first, and then decrease, while the open-circuit voltage continues to increase, resulting in the overall conversion efficiency following the trend of initial increase and subsequent decrease. Among the six materials studied, Cu02 is the best emitter material, which provides the highest conversion efficiency of solar cells.