Versatile strategies for improving the performance of diamond wire sawn mc-Si solar cells

Unlike conventional multi-wire sawn (CMWS) multi-crystalline silicon (mc-Si) wafers, diamond wire sawn (DWS) mc-Si wafers textured by conventional acidic solution of HF/HNO3 are not suitable for solar cells because visible saw marks set significant barriers in both cell performance and surface appearance. In this work, we have employed versatile strategies based on metal-assisted chemical etching (MACE) technique to eliminate the saw marks and realize effective surface textures on DWS mc-Si wafers, including nano-texture (N-T), micro-texture (M-T) and nano/micro-texture (N/M-T). Especially, benefiting from the tradeoff between optical gain and electrical loss, the efficiency of 18.45% for N/M-T based DWS mc-Si solar cells with a standard wafer size of 156×156 mm2 is reported to be higher by an absolute 0.57% compared with that of CMWS mc-Si solar cells (17.88%). Our work provides ways of fabricating DWS mc-Si solar cells with high efficiencies and satisfactory visual appearance.