Cost-effective bifacial silicon solar cells with 19% front and 18% rear efficiency

Commercially available silicon solar cells still suffer from relatively low efficiencies and high fabrication costs. One possibility for cost reduction of photovoltaic energy are bifacial cells. This paper presents a new cost-effective bifacial solar cell which combines the excellent surface passivation properties of remote-PECVD silicon nitride films with a simple alloyed local Al back surface field (BSF). The low deposition temperature of the remote-PECVD silicon nitride films (375°C) allows to form the metal contacts prior to the silicon nitride deposition, eliminating photolithographic methods from the fabrication process. On FZ-Si wafers, the new bifacial cells demonstrate independently confirmed 1-Sun efficiencies of 18.4%/18.1% (front/rear) for a rear-optimized design and 19.4%/16.5% for a front-optimized version. Installed in front of a white wall (30% reflected light), the latter cell would produce a power output above 24 mW/cm²