Stability optimization of TiO2 dye-sensitized solar sub-modules in Z-type series interconnection

Dye sensitized solar cells (DSSC), one of the promising technology for renewable energy, has reached good performance in laboratory scale. In order to be implemented in practical use, it has become a necessity to enlarge the small size DSSC into large area (module) and to optimize stability of the module. In this study, dye sensitized solar sub-modules were fabricated with a size of 33 mm × 50 mm consisting of two active cells, each with a size of 10 mm × 50 mm, which are interconnected in type-z series. Working electrode of the sub-modules was prepared using a screen printing technique to deposit the TiO2 paste on glass conductive substrate with TiCl4 pre-treatment and post-treatment. The sub-modules were assembled using two types of sealant to investigate the effect of sealant on lifetime of the sub-module. I-V measurement using sun simulator with light intensity of 500 watt/m2 was applied twice in the range of six days to obtain the sub-module lifetime stability result. From the first I-V test, the highest photoconversion efficiency of the sub-module was 3.58%. In the second test results, the photoconversion efficiency was decreased significantly with the lowest percentage of efficiency degradation was 95.81%.