Efficiency enhancement breaking 10 % barrier in black dye sensitized solar cells through co-sensitization
Haifa Alharbi, Ali Hamzah Alessa, Ahmad Fawzi Qarah, Abrar Bayazeed, Sara A. Alqarni, Arwa Alharbi, Hanadi A. Katuah, Nashwa M. El‐Metwaly
Abstract
This study presents a comprehensive investigation of the novel organic dye MDJ-1 and MDJ-2 as a co-sensitizer in dye-sensitized solar cells (DSSCs), along with well-known Ru (II)-based black dyes. The sensitizer MDJ-1 and MDJ-2 consists of a diphenylamine donor (DPA) scaffold linked with an electron-withdrawing moiety, such as 2-cyano-2-(4-carboxyphenyl)ethylene for MDJ-1 and a rodanine-3-cyanoacetic acid acceptor for MDJ-2 . This study demonstrates the significant influence of sensitizers with different anchoring units on the photovoltaic parameters of DSSCs using black dye sensitizers. This approach exploits the ability of carboxylic groups to bind to Brønsted acids on TiO 2 surfaces, reducing competitive adsorption between dyes. This enhances the dye coverage on the TiO 2 surfaces, minimizes electron recombination, and consequently, increases the photovoltage. Furthermore, the study thoroughly examined the effect of the sensitizer/co-sensitizer concentration on device performance. The results indicate that devices fabricated using the co-sensitizer ( MDJ-1 – 2 + black dye) outperform those fabricated using the black dye alone. The co-sensitized device that utilized ( black dye + MDJ-1 + CDCA ) demonstrated the highest photovoltaic performance, with a power conversion efficiency of 10.50 %. These findings provide valuable insights into optimizing DSSCs by selecting compatible co-sensitizers at appropriate concentrations to improve the device performance.