Improved fill-factor for the double-sided buried-contact bifacial silicon solar cell

Despite the commercial success of buried-contact solar cells, the performance of early generations of these devices has been limited by an effective high rear-surface recombination velocity. For a number of years, the double-sided buried-contact bifacial (DSBCB) solar cells have demonstrated improved rear-surface passivation with corresponding improvements in current and voltage. In the past, however, the fill factors of these devices have been significantly degraded due to shunting of the rear floating junction. These limitations have been overcome through the use of much higher sheet resistivities for the rear n-type layer. Experimental devices based on this new approach have achieved fill factors approaching 82% while simultaneously achieving open-circuit voltages in the vicinity of 670 mV. Efficiencies in the range 17-18% without texturing, anti-reflection coatings, any form of light trapping, or even rear reflector have been achieved on float-zone material.