Selective laser sintering of TiO2 nanoparticle film on plastic conductive substrate for highly efficient flexible dye-sensitized solar cell application

Abstract

In this paper, we report a novel selective laser sintering of TiO₂ nanoparticle (Degussa P25) film on plastic conductive substrates for highly efficient flexible dye-sensitized solar cell (DSC) applications. The so-called “selective sintering” means that the absorbed laser energy can effectively promote the electrical contacts between the TiO₂ nanoparticles, but does not cause damage to the plastic conductive substrate. The choice of the near-infrared (wavelength = 1064 nm) laser source is critical for the effectiveness of the laser sintering. The laser sintering technology can effectively decrease electron transport resistance and increase recombination resistance of the TiO₂ nanoparticle film characterized by electrochemical impedance spectroscopy and transient photovoltage/photocurrent decay measurements, resulting in much improved charge collection efficiency. Thus, compared to the reference sample, the laser sintered film has achieved an improved short-circuit current density from 9.2 to 10.4 mA cm⁻², fill factor from 0.71 to 0.77, and solar conversion efficiency from 4.5% to 5.7%. The fast and effective selective laser sintering technique has great potential to be integrated into scalable roll-to-roll manufacturing of highly efficient flexible DSCs.