Edge isolation of solar cells using laser doping

Abstract

A technique of using laser doped isolation lines to separate shunted edge regions from the active area of a solar cell is presented. Photoluminescence images are used to investigate the effectiveness of the edge isolation. Screen-printed silicon solar cells are fabricated to demonstrate the ability of the technique to remove the shunt path from the front emitter to rear contact whilst minimising edge recombination. It is found that a reduction of J02 by on average a factor of more than three is possible compared to the standard method of cleaving for these laboratory cells, yielding an average improvement in FF of 1.7%abs, and 0.5%abs efficiency increase. The J02 values achieved using this process are comparable to those achieved on solar cells with edges passivated with a thermal oxide.