High efficiency on boron emitter n-type Cz silicon solar cells with industrial process

Abstract

Summary form only given. The fabrication of n-type solar cell using industrial process is presented in this study. The boron emitter was formed using novel diffusion technique with BCl ₃ precursor and the passivation was made by means of dry oxidation. The influence of the grid coverage ratio on the backside was studied and an optimized value of 5% was found. Efficiencies above 19.0% were obtained on 125PSQ Cz wafers. We also report a independently certified efficiency of 18.7% measured by Callab on a special bifacial chuck. A difference in short-circuit current was observed compared to the use of a full chuck. Stability of the fabricated cell was investigated at 50°C under AM1.5 illumination. After over 100 h exposures, the cell efficiency was improved of 0.2% due to a slight increase in the V _oc , leading to a maximum efficiency of 19.3%. Potential improvements in efficiency were presented by means of numerical simulations. The optimization the emitter & BSF profiles should lead to efficiency close to 20%. Finally, small modules of 2×2 cells were fabricated and measured to analyse the evolution of the cell performance at a module level. Losses in FF and current were observed will be analysed in a future work.