INVESTIGATION OF LOW TEMPERATURE SINTERING Cu-DOPED GRAPHITE INK AS BACK ELECTRODE OF CdTe SOLAR CELLS

This paper has investigated the change of CdS/CdTe thin film crystal microstructure after CdCl2 vapor post-treatment and the effect of Cu- and Cu compound (Cu2-xZnxTe)-doped graphite ink as back electrode on the performance of CdTe solar cells. It reveals that the post-treatment of CdCl2 vapor significantly increased crystal size of both CdS and CdTe thin films and improved their crystal structure. The post-treatment of CdTe with CdCl2 vapor and the addition of Cu2-xZnxTe in graphite ink as back electrode of CdS/CdTe solar cells eliminated the etching process before back electrode was applied, enhanced the efficiency of CdTe solar cells from 6.9% using pure graphite to 13.5%, reduced the optimal sintering temperature of graphite ink from 240 degrees C to 200 degrees C, and greatly improved the thermal stability of CdTe solar cells.