Improved Dye Sensitized Solar Cells Efficiency and Stability Using Co-Sensitization Method of Organic Dyes

DSSCs have drawn much research attention in recent years as they provide numerous potential advantages, such as high energy conversion efficiency, easy fabrication process, colorful and transparent features, and low manufacturing costs. In this work, we used co-sensitization method to enhance the efficiency and stability of dye sensitized solar cells. The organic XY1B dye was used as a co-sensitizer with organic Y123 dye. The ruthenium-based Z907 dye was used as a reference. The absorption spectra of the co-sensitization dye, XY1B:Y123, are more intense as compared to that of individual dyes, XY1B and Y123. The co-sensitized TiO2 films exhibited broader band in the region of $300-450 \mathrm{~nm}$ and in the region of $525-625 \mathrm{~nm}$. XY1B:Y123 sensitized device achieves the highest performance with an efficiency of 5.47% resulting from highest fill factor (FF), short-circuit current density (Jsc), and open-circuit voltage (Voc) are $57.48 \%, 10.69 \mathrm{~mA} / \mathrm{cm}^{2}$, and 756.77 mV, respectively. A stability test of the DSSC with various organic dyes and ruthenium dye was conducted in an air atmosphere. The co-sensitized device shows excellent stability. After 30 days, the device efficiency (5.22%) slightly drops by 2.7% relative to initial efficiency (5.36%). In comparison, the device efficiency of ruthenium-based dye Z907 (3.19%) drops by $\mathbf{2 2. 4 \%}$ relative to initial efficiency (4.11%).