20.63 % nPERT cells and 20% PR gain bifacial module

In this study, comprehensive efforts were conducted to improve conversion efficiency for n-type passivated emitter, rear totally-diffused (nPERT) cells. Key technologies such as boron emitter, phosphorous back surface field (BSF), KOH texturization, and metallization were all investigated and optimized. nPERT cells with 20.63 % efficiency were successfully produced with processes based on homogeneous diffusion and screen-printed metallization. To our knowledge, this is the highest demonstrated efficiency for nPERT cells using boron diffusion. Additionally, we report outdoor performance of a bifacial module made with our nPERT cells, which indicates a performance ratio (PR) gain of more than 20% compared with a conventional p-type module.