Synthesis of blue organic dyes and their application as sensitizers Dye Sensitized Solar Cells

Dye-sensitizer solar cells (DSSC) are currently considered one of the most promising alternatives to traditional silicon solar cells . The research activity in this field is mostly focused on the design and synthesis of new organic dyes with potential application in this kind of devices. The synthesis of new dyes with high molar extinction coefficient and specific color (blue in particular) in order to increase the aesthetic properties and ease their integration in buildings and objects are the main focus in the research in the field of DSSC. Aiming to this goal, we selected as new auxiliary acceptor group the (E)-3,3'-bifuranylidene-2,2'-dione (Figure 1) , a strong electron-withdrawing system which was firstly prepared in 1882. The synthesis of this dye has been optimized and its derivatization using Pd-catalysed cross-coupling reactions has been firstly accomplished. Then, two new D-A-?-A dyes containing the (E)-3,3'-bifuranylidene-2,2'-dione as auxiliary acceptor group have been designed, synthesized and characterized: the two new dyes showed an intense blue color in solution and, when adsorbed on a TiO2 electrode, both a broad absorption of the red/near-infrared light between 500 and 800 nm and right electrochemical potentials for a proper use in DSSCs.