A comprehensive investigation of the potential of metal assisted chemical etched (MACE) nano-textures over conventional micron-sized iso-textures for industrial silicon solar cell applications. (December 2021)

• Record Type: Journal Article
• Authors: Sreejith, K.P.; Sharma, Ashok Kumar; Basu, Prabir Kanti; Kottantharayil, Anil
• Is Part Of: Solar energy. Volume 230(2021)
• Page Start: 874
• Page End: 882
• Publication Date: 2021-12
• Subjects: Multi-crystalline silicon cells -- Diamond wire sawn wafers -- Metal assisted chemical etching -- Acid texturing -- High efficiency industrial silicon solar cells; Solar energy -- Periodicals; Solar engines -- Periodicals; 621.47
• DOI: 10.1016/j.solener.2021.10.035
• Languages: English
• ISSNs: 0038-092X

Abstract

Abstract: We present a comprehensive comparative analysis of acid textured and MACE (Metal Assisted Chemical Etching) nano-textured multi crystalline silicon (mc-Si) solar cells processed in an industrial cell line in terms of performance parameters. The batch average open circuit voltage of nano-textured solar cells was marginally lower and the measures for improving the same are discussed. Batch average short circuit current (J S C ) and fill factor (FF) were respectively 0.65 mA-cm −2 and 0.7% (absolute) higher for MACE nano-textured solar cells. Significantly lower surface reflectance in MACE nano-textured cells in the blue and near infrared regions are found to be the reason for the enhancement in J S C . The main component of FF gain is identified as the lower series resistance in MACE cells. The contact formation mechanism in screen printed mc-Si solar cells, investigated using scanning electron microscopy, revealed that the elevated portions at the boundaries of the textures act as favorable sites for silver crystallite precipitation. A larger areal density of such sites is observed on the MACE nano-textured surface than in case of acid textured solar cells, leading to a much lower series resistance. The results suggest the potential for the application of MACE in the more popular mono-crystalline silicon cell technology for further reduction of contact resistance. Alternatively, MACE may be used to obtain similar contact resistance with lower amount of silver paste, compared to iso- and pyramid textured solar cells. Highlights: MACE nano-textures offer lower reflection and higher fill factor than iso-textures. Gain in fill factor in nano-textured cells is due to lower series resistance. Elevated portions of textures are the favorable Ag crystallite precipitation sites. Large area density of MACE nano-textures lower the series resistance significantly.