On the Ink Jetting of Full Front Ag Gridlines for Cost-Effective Metallization of Si Solar Cells

Abstract

In this letter, we report on the ink-jet full gridline cells with three different Ag dosages (70, 90, and 130 mg) on 75-Ω/sq emitters. We observed that the open-circuit voltage ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">OC</sub> ), short-circuit current density ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">J</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">SC</sub> ), and fill factor ( <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FF</i> ) were highest for the 130-mg dose and decrease thereafter as the Ag dosage decreases. Because of the decreased <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FF</i> with decreasing Ag dosage, the efficiency followed the same trend. However, we demonstrated, for the first time, fully ink-jetted front Ag gridlines with an <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">FF</i> of 0.765 and efficiency of 18.4% on 239-cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> commercial CZ wafers with a sheet resistance of 75 Ω/sq . Noteworthy is the achievement of 17.8% efficiency with only 70 mg of Ag, which is ~ 68% less Ag than that used on cells with screen-printed gridlines. This represents a Ag cost saving of ~ $0.245 per 6-inch wafer compared to the screen-printed counterpart with 220 mg of Ag.