Formation of a conductive grid on thin film modules glass by laser-patterning

In thin film solar modules, transparent conductive oxides (TCOs) are commonly used as a front contact. The limited electrical conductivity and optical transparency of TCOs reduce the efficiency of thin film modules, so a compromise must be achieved between low-light absorption and good electrical conduction. In this work a new method for increasing the electrical-conductivity of TCO films and maintaining high optical transparency in solar modules by creating micron-sized metalized grooves in the substrate is presented. The grooves were machined into the glass substrate using a 266 nm pulsed UV laser and a relevant optical setup. Initial results show that ultra-fine gridlines down to 10 μm width with fully metalized sidewalls can be achieved. This is a factor of ten smaller than the gridlines produced by screen-printing. This paper presents the procedures for masking, laser processing and metallization and analyzes the impact this technique would have on solar cell performance.