Laser Sintering of TiO2 Films for Flexible Dye-Sensitized Solar Cells

In this study, laser sintering of TiO2 nanoparticle films on plastic substrates was conducted in order to improve the incident photon-to-electron conversion efficiency (IPCE) of flexible dye-sensitized solar cells (DSCs). Lasers with different wavelengths (355 nm and 1064 nm) were used to process the TiO2 electrodes. With an optimized processing parameter combination, the 1064 nm laser can sinter 13 mu m thick TiO2 films uniformly, but the uniform sintering cannot be achieved by the 355nm ultraviolet (UV) laser, since the films possess a high absorption ratio at 355 nm. The experimental results demonstrate that the near-infrared laser sintering can enhance the electrical connection between TiO2 nanoparticles without destroying the flexible plastic substrate, reduce the transmission impedance of electrons and increase the absorption rate of incident light. Furthermore, the charge collection efficiency, fill factor, and short-circuit current have all been improved to some extent, and the solar conversion efficiency increased from 4.6% to 5.7%, with an efficiency enhancement reaching 23.9%.