Over 700 mV IBC Solar Cell by Optimizing Front Surface Field Passivation

Abstract

In this article, the front surface field (FSF) passivation of n-type interdigitated back contact (IBC) solar cell was studied and a method to improve the FSF passivation performance of n-type IBC solar cell was proposed. We optimized the phosphorus diffusion on the front surface of IBC solar cell to form a field passivation structure with low surface concentration and shallow junction depth. The surface recombination rate was calculated using EDNA2. Solar cell parameters were simulated by Quokka, and finally we did experiment verification. The results showed that when the deposition time and flow rate of POCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> in the phosphorus diffusion process time is 3 min and POCl <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> flow rate is 80 sccm, the front surface saturation current density (J <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> ) is reduced to 3.71 fA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , corresponding to the front surface recombination rate of 100 cm/s. On solar cells, open-circuit voltage reached 704 mV, the average conversion efficiency of IBC solar cell exceeded 24%, and the highest conversion efficiency reached 24.28%.