Non-vacuum printing process for CIGS solar cells on rigid and flexible substrates

ISET has developed an ink based non-vacuum process for fabricating thin film CIGS solar cells both on rigid and flexible substrates. The key benefits of this process are (1) controlled stoichiometry of the absorber layer resulting in a high process yield, (2) high materials utilization and (3) low cost of processing equipment. The combined effect of these attributes of this process is low-cost manufacturing of CIGS solar cells. Using this process, ISET has fabricated CIGS solar cells on glass and other flexible substrates. The highest conversion efficiency observed in CIGS solar cells fabricated is 13.6% on glass substrate and 10.1% on Mo foil. Because this process uses inks, a number of relatively low cost printing technologies are available for processing absorber layers in CIGS solar cell. The basic principles of this novel approach and the results obtained are discussed in this paper.