Comparison of two ways using Ag nanoparticles to improve the performance of dye-sensitized solar cells

The photoanode plays an important role in the dye-sensitized solar cells (DSSCs). Herein, two ways adding Ag nanoparticles into the photoanode successfully improved the performance of DSSCs. One is that Ag nanoparticles were mixed with P25 powders (named mixture with Ag), the other is that a thin layer of Ag nanoparticles was added between FTO and P25 (named Ag layer). As a result, the best DSSCs based on the two ways achieved a power conversion efficiency (PCE) of 7.09% (mixture) and 6.97% (layer) respectively, indicating a ∼19% enhancement compared with that of the pure P25 DSSC (5.94%). By comparing, the mixture with Ag DSSCs was found to show better dye adsorption, catalytic effect and optical absorption by the local surface plasma resonance (LSPR) effect, and the Ag layer DSSCs was mainly attributed to the Mie scattering effect and improved interfacial charge transfer. However, no matter what kind of ways, the excess and concentrated Ag nanoparticles were found to become the recombination centers to boost the interfacial recombination of photo-excited charges.