717-mV open-circuit voltage silicon solar cells using hole-constrained surface passivation

Abstract

A virtual saturation of the supply of holes leading to an injection level dependent reduction in surface recombination velocity has been shown to be responsible for the improved performance of recent high efficiency silicon solar cells. By fabricating test cells taking advantage of this and other recombination reduction mechanisms, improved open-circuit voltages of 717 mV have been independently confirmed for experimental silicon cells. These voltages correspond to saturation current densities of 25 fA/cm2 at 25 °C, also the lowest demonstrated for a silicon junction device. Further improvement in both voltage and cell efficiency is expected to result from this work.

Ultra-thin single crystal silicon modules capable of 450 W/kg and bending radii <1mm: Fabrication and characterization

“…The higher current density suggests that there is greater carrier recombination in the 4% module than in the 13% one. Passivation of the cell can be further improved given that other high-performing cells have achieved values as small as 2.5 X10 -14 A/cm 2 [9] for J oe . By comparing mini modules that did not have missing cells but that did have missing silicon due to tear offs, we can attribute up to 2.5% absolute efficiency losses due to recombination.…”

Silicon solar cells: evolution, high-efficiency design and efficiency enhancements

“…The total contribution from diffused regions has to be less than 10 fA cm-2 and 4 fA cm-' of cell surface area respective-ly. Values as low as 25 fA cm-' of diffused surface have been demonstrated in experimental cells [48].…”

“…Using the values of 1.66 x IOw3' cm6 sC1 and 1.00 x 10" cm-3 at 300 K, respeo tively, gives a value of the open-circuit voltage limits of 748 mV for a 280 pm thick cell and 770 mV for an 80 flm thick cell, both at 25OC. Current experimental highperformance PERL cells give experimental values of just over 700mV with test structures giving values up to 717 mV [48].…”