Development of silicon solar cells for six-junction tandem stack cells

This paper presents the development of small (2.5×8.0 mm²) silicon solar cells, to be used in a six-junction tandem device. PC1D, numerical modeling and quasi steady state photoconductance (QSSPC) measurement were used to predict the targeted efficiency of silicon solar cells. Early batch of cells had problems of shunting, series resistance and high carrier recombination. Various techniques - junction isolation, pin-hole analysis, diffusion drive-in, light-induced plating, lifetime degradation studies and implied-Voc - were used to improve the performance of the solar cells.