Performance degradation of commercial Ga-doped passivated emitter and rear cell solar modules in the field

Gallium-doped passivated emitter and rear cells (PERCs) showed great promise for future advanced highly efficient solar cells. However, there is a lack of information available regarding the field degradation of gallium-doped PERC solar modules. In this work, the field degradation of gallium-doped PERC solar modules is investigated and compared with the field degradation of stabilized boron-doped PERC solar modules. It is remarkable that the peak power degradation curves of the gallium-doped PERC solar modules present two degradation stages which might be attributed to synthetical results of light-induced degradation (LID) and light and elevated temperature-induced degradation (LeTID). The extents of degradation for the gallium-doped PERC solar modules are smaller than that of the stabilized boron-doped PERC solar modules. The LID characteristic of the gallium-doped PERC solar modules is caused by the presence of residual boron in Ga-doped Cz-Si wafers which has been demonstrated by the results of inductively coupled plasma-mass spectrometry. Moreover, a comparative study of daily yield for gallium- and boron-doped PERC photovoltaic arrays is carried out. It was found that the gallium-doped photovoltaic array has a higher energy yield and shows a better performance ratio than the boron-doped photovoltaic array. The reason is that the performance degradation and its induced mismatch loss of gallium-doped solar modules in the field are smaller than that of the boron-doped solar modules.

Automated summary

The field degradation of gallium-doped PERC solar modules was found to be smaller than that of stabilized boron-doped PERC solar modules, possibly due to the combined effects of light-induced degradation and light and elevated temperature-induced degradation.