Metallization process optimization of HIT solar cell for high current density and silver reduction

The Silicon heterojunction (SHJ) solar cell belongs to the most viable cell structure that enables low cost as well as high efficiency. For SHJ cells, silver (Ag) paste has been used through screen-printed process that is hardenable at low temperature. The procedure of screen printing is essential for improving the electrical properties because it allows electrodes to make good contact with the top layer of solar cells. This paper describes the experimental procedure to optimize the process condition for achieving comparatively high efficiency with minimum usage of Ag consumption. It was noticed that adequate contact among electrodes and uppermost transparent conductive oxide layer in SHJ solar cell depending considerably on squeeze speed, squeegee pressure, scraper speed, curing time and temperature. By controlling the snap-off distance of 1.4 mm, squeegee pressure at 0.3 MPa, scraper speed of 10 mm/sec, squeegee speed of 170 mm/sec, curing time of 20 min and curing temperature of 190 °C respectively, we achieved comparatively high efficiency of 22.46 %.