Record Large-Area p-Type CZ Production Cell Efficiency of 19.3% Based on LDSE Technology

A record independently confirmed production cell efficiency of 19.3% is presented for a large-area p-type Czochralski (CZ) silicon solar cell, based on the University of New South Wales (UNSW) laser-doped selective emitter technology. In this paper, the innovative and patented laser-doping technology is simply added to a standard Centrotherm turnkey line, operating with a modified process and the addition of the laser-doping and light-induced plating steps. Impressively, this record efficiency is achieved by using standard commercial grade p-type CZ-grown silicon wafers on standard production equipment and exceeds the previous independently confirmed record for any technology of 19.2% using a standard aluminum back-surface field with full rear coverage. The avoidance of laser-induced defects is discussed in this paper to overcome previous limitations of the laser-doping technology using conventional Q-switched lasers or the laser chemical processing method. It is demonstrated that the use of appropriate lasers can avoid defect formation through thermal cycling while still allowing for the sufficient mixing of dopants and allow laser doping to be performed through a standard SiN layer with contacts formed through a self-aligning metallization scheme.