Modification on C219 by coumarin donor toward efficient sensitizer for dye sensitized solar cells: A theoretical study

• Three dyes with different electron donors derived from C219 for DSSC were designed.
• A set of key parameters affecting the efficiency of the cell have been discussed.
• Dye 3 with Coumarin donor shows higher Voc and Jsc than that of champion dye C219.

Dye sensitized solar cell sensitized by organic dye C219 (Chem. Mater, 2010, 22, 1915–1925) has reached the record efficiency (η) of 10.1% with comparable short-circuit current density (Jsc) but relatively lower open-circuit photovoltage (Voc) as compared to that of ruthenium-based cells. With the motivation of further enhancing Voc, we designed three dyes 1–3 with different electron donors, i.e. carbazole, indoline and coumarin. Based on the theoretical analysis of the conduction band energy shift of TiO2, electron injection rate and electron lifetime, the three designed dyes all show larger Voc than that of C219. On the other hand, 3 should also have larger Jsc compared with that of C219 due to its red-shifted spectrum and higher light harvesting efficiency. Thus we expect that the cell sensitized by 3 could exhibit both larger Voc and Jsc in comparison to the champion C219-based cells.

A theoretically designed coumarin dye shows both higher Voc and Jsc potential compared with champion dye C219 through the reliable DFT/TDDFT calculations on semiconductor/sensitizer/electrolyte interfacial interaction.Figure optionsDownload as PowerPoint slide