Functionalized Carboxylate Deposition for rapid sensitization of dye-sensitized solar cells

• Gas-phase deposition technique called Functionalized Carboxylate Deposition introduced.
• This technique was used for sensitization of nanoporous TiO2 photoelectrodes.
• Dye loading time was reduced by 98% while maintaining or increasing cell efficiencies.

The current state-of-the-art dye loading process for modern dye-sensitized solar cells (DSCs), essentially unchanged for the last 24 years, entails dip-coating nanoporous TiO2 photoelectrodes in a concentrated solution of dye for an average of 16 h. This process constitutes up to 80% of the fabrication time, leads to significant dye waste, and necessitates the use of organic solvents. A promising gas-phase deposition technique, coined Functionalized Carboxylate Deposition (FCD), was used to rapidly deposit a self-assembled monolayer of targeted α-carbon modified carboxylic acid containing dye molecules on TiO2 photoelectrodes. The FCD process successfully reduced the dye loading time by 98% (i.e., 15–20 min compared to an average of 16 h). Moreover, the FCD-sensitized photoelectrodes produced DSCs with equivalent or higher efficiencies than dip-coating for the dyes used (both in this study and by other researchers). The performance of FCD dye sensitization in this study indicates its potential applicability as a foundational technology for rapid fabrication of efficient DSCs.