Mesoporous TiO2 film modified with a sol–gel based interconnecting network for boosting the dye-sensitized solar cell performance

• Small-size titania nanocrystals are synthesized via robust sol–gel process.
• Sol–gel titania forms interparticle-bindings in the P25 matrix.
• Sol–gel induced networks reduce the interfacial impedance.
• Sol–gel modification reduces the processing time and energy consumption for fabrication.

In this study, a porous TiO2 thin film was modified with a robust sol–gel process to form interconnected nanoparticle networks for facilitating charge transfer in a dye-sensitized solar cell. Compared to the conventionally prepared photoanode using only P25 TiO2 nanoparticles, such a unique processing method could reduce the interfacial impedance by ~ 18% (from 27.6 Ω to 22.5 Ω) by forming interparticle-bindings between the P25 TiO2 nanoparticles with the sol–gel TiO2. Such a processing method could improve the photocurrent density by ~ 30% (from 10.07 mA/cm2 to 13.07 mA/cm2) and consequently it results in a ~ 20% photovoltaic efficiency improvement of dye-sensitized solar cell (from 4.83% to 5.81%). In addition to the photovoltaic performance enhancement, such a facile method with reduced processing time and energy consumption provides the possibility of developing high performance and cost-effective dye-sensitized solar cells.