Influence of inverted pyramid texturization on front metallization and performance of crystalline silicon solar cells

Abstract

The silicon surface texturing is an essential part for the fabrication of crystalline silicon solar cells to increase the conversion efficiency. By adjusting the etching texturing condition, inverted pyramid (IP) and upright pyramid (UP) texturization were prepared on crystalline silicon substrates for fabrication of PERC solar cells. The surface morphology not only affects the light trapping but also impacts electrode shading loss and front electrode contact interface. The IP texturization presents better anti-reflective performance due to more common light paths and narrower silver grids owing to less flow of Ag paste on concave blocked structure, both of which results in the higher short-circuit current density (Jsc). Yet in terms of front Ag/Si contact interface, the IP texturization causes more Ag crystallites and more surface recombination under the present condition suitable for UP texturization because of more edges on the upper part of IP, which leads to the lower open-circuit voltage (Voc). The final conversion efficiency of IP solar cells (23.61 %) is 0.06 % higher than that of UP solar cells (23.55 %). An improvement about 0.07 mA/cm2 of Jsc was achieved with IP samples and Voc has a decrease of 0.3 mV caused by the surface recombination on IP texturization. In summary, the structural characteristics of IP results in lower reflectivity and less electrode shading, while Ag/Si contact interface could be optimized by adjusting the processing condition, ultimately promising the higher efficiency.