Wafer thickness, a pivotal design parameter that accounts for up to 50% of current solar cell material costs 49 and used by the PV industry to sustain silicon solar cells economically viable, 50 demonstrates significant dependency on location.
And additional machining processes is required to make samples, which generate non-original defects and further affect the fracture strength. So far, there is no standard test method for evaluating the mechanical strength of silicon wafers, because of a large aspect ratio of photovoltaic silicon wafers.
However, silicon's abundance, and its domination of the semiconductor manufacturing industry has made it difficult for other materials to compete. An optimum silicon solar cell with light trapping and very good surface passivation is about 100 µm thick.
Currently, the thickness range of n-type silicon wafers is 120 μm–150 μm, while the thickness range of p-type silicon wafers is 140 μm–150 μm. By 2034, the thickness of n-type silicon wafers is expected to decrease to 100 μm, and the thickness of p-type silicon wafers to 130 μm .
Then, we investigate the bifacial silicon cell and show that its optimal wafer thickness should be 1.67–2.89 times thicker than its monofacial counterpart, depending on the geographical region.
According to the “International Technology Roadmap for Photovoltaic”, M10 (182 mm × 182 mm) and G12 (210 mm × 210 mm) silicon wafers are dominating the market, and The market share of G12 and larger silicon wafers is expected to exceed 40 % in 2028 [9, 10].