An interdigitated back contact solar cell with high-current collection

Internal current-collection efficiencies greater than 90 percent and energy-conversion efficiencies of 18-percent at 30 suns have been measured on a laboratory version of the interdigitated back contact (IBC) solar cell. The quantum efficiency at 600 nm was greater than 90 percent which implies a minority carrier lifetime of greater than 350 µsec and a front surface recombination velocity of less than 30 cm/sec on the better devices. The processing steps on which the high-current collection in the IBC cell depends will be discussed.