Optimizing anti-reflection and surface passivation for n-type back-contact back-junction silicon solar cells using SiNx/SiON stack layers: Insights from quokka simulation

The back-contact back-junction (BC BJ) cell configuration's unique design, with the emitter and rear contact on the back, allows for easier and more effective carrier collection from the rear. This study utilized the non-vacuum break method to create SiN_x/SiON dual layers; these layers were then used as both an anti-reflection and passivation layer to enhance the performance of the BC BJ cells. Both experimental and simulation approaches were employed to optimize these performances. By integrating the advantageous characteristics of the SiN-rich SiN_x layer and the SiON layer, the stacked SiN_x/SiON layer demonstrates remarkably low surface recombination with an average surface reflectance of 3.95 % and 5 cm/s, respectively. Through simulation, introducing the SiN_x/SiON stack on the front side of the BJ BC results in an increase of up to 3.4 mA/cm2 in short-circuit current density and 26 mV in open-circuit voltage, as compared to using a single SiN_x layer. The incorporation of the SiN_x/SiON stack resulted in an approximately 14.59 % efficiency enhancement for BJ BC solar cells. This success motivates further research into non-vacuum-based optimization techniques for BJ BC cells.