Influence of SILAR deposition cycles in CdS quantum dot-sensitized solar cells

The cadmium sulfide (CdS) quantum dots (QDs) were deposited on the commercial (Degussa-P25) TiO2 nanostructures by successive ionic layer adsorption and reaction (SILAR) method. Three types of films were prepared with CdS 9, 12 and 15 cycles. The PXRD, UV-Vis-NIR absorption and J-V measurements were taken for the CdS QDs deposited for 9, 12 and 15 cycles and the results were compared. The CdS sensitized electrode prepared using 12 cycles of SILAR produces an efficiency of 1.45% on using a liquid (I-/I-3 (-)) electrolyte and platinum counter electrode under the illumination of 100 mW/cm(2) which shows the best power conversion efficiency compared with CdS 9 and 15 cycles respectively. Total charge collection efficiency was increased upto 12 deposition cycles and it started to decrease beyond 12 cycles. This might be due to the changes in the photo adsorption behavior of CdS QD as a function of deposition cycles.